Publications
| Title | Abstract | Year Filter | PMID(sorted descending) Filter |
|---|
| heart and t-lymphocyte cell surfaces both exhibit positive cooperativity in binding a membrane-lytic toxin. | cobra venom cytotoxins (ctx) have been shown to disrupt cells as different as immunocytes, skeletal myocytes, erythrocytes and tumor cells. nevertheless, even subpopulations of tumor cells are differentially susceptible to ctx by an order of magnitude. in the present study, our objective was to compare ctx-specific binding with cytolytic potency for two disparate cell types in vitro. we investigated the lytic activity of cytotoxin-iii from naja naja atra (nna, fraction d) using heart cells and h ... | 1996 | 8699476 |
| cdna sequence analysis and expression of cardiotoxin v and a new cardiotoxin vii from naja naja atra (taiwan cobra). | the cdnas encoding cardiotoxin v and a new cardiotoxin vii were constructed from the cellular rna isolated from the venom glands of naja naja atra by reverse transcription-polymerase chain reaction. although 95% nucleotide sequence homology was observed with the two cardiotoxins, there were nine amino-acid substitutions between cardiotoxin v and cardiotoxin vii. the cardiotoxins were subcloned into the expression vector pet 20b(+) and transformed into bl21(de3) e. coli strain. the expressed prot ... | 1996 | 8679666 |
| effect of chaotropic denaturant on the binding of 1-anilino-8-naphthalene sulfonic acid to proteins. | 1-anilino-8-naphthalene sulfonic acid (ans), a hydrophobic dye, is widely used to monitor conformational changes occurring in proteins during their folding/unfolding. using cardiotoxin iii (whose conformation remains unperturbed even in 6 m urea) from the taiwan cobra (naja naja atra) venom, it is demonstrated that chaotropic denaturant such as urea directly competes with the interaction between ans and the protein. the results presented in this report, in our opinion, has significant implicatio ... | 1996 | 8645725 |
| phospholipase a2 from naja naja sputatrix venom is a muscarinic acetylcholine receptor inhibitor. | a variety of snake venoms was tested for the ability to inhibit the binding of antagonists to specific muscarinic acetylcholine receptors (machrs); the highest activity was found in the venom of naja naja sputatrix. the active principle in this venom was isolated by column chromatography on sephadex g-50, sephadex g-150, and cm-sephadex c-25. the final preparation was homogeneous as determined by polyacrylamide gel electrophoresis and hplc; about sevenfold purification was achieved with a yield ... | 1996 | 8638927 |
| 2,2,2-trifluoroethanol induces helical conformation in an all beta-sheet protein. | the effect of 2,2,2-trifluoroethanol (tfe) on the structure of an all beta-sheet protein, cardiotoxin analogue ii (ctx ii), from the taiwan cobra (naja naja atra) is studied. using circular dichroism studies, it is found that higher concentrations of tfe induced a structural transition from beta-sheet to alpha-helix, both in the native state (nctx ii) and in denatured but not disulfide reduced ctx ii (dctx ii) samples. the beta-sheet to alpha-helix conversion is shown to be cooperative. however, ... | 1996 | 8630070 |
| role of interferon-gamma against invasion by toxoplasma gondii in a human monocytic cell line (thp1): involvement of the parasite's secretory phospholipase a2. | we examined the role of ifn gamma in protection against toxoplasma gondii in the monocytoid cell line thp1. the addition of ifn gamma to cultured infected thp1 cells reduced the number of parasitized cells without altering intracellular multiplication during the first 24 hr. this reduction was potentiated by bacterial lipopolysaccharide (lps). we also examined the role of an enzyme important for t. gondii cellular invasion, secretory phospholipase-a2 (spla2) and its relation with ifn gamma-induc ... | 1996 | 8620549 |
| cdna sequence analysis and expression of cardiotoxins from taiwan cobra. | the cdnas encoding cardiotoxins i, iii and n were constructed from the cellular rna isolated from the venom glands of naja naja atra by reverse transcription-polymerase chain reaction. a high degree of sequence homology was observed with the three cardiotoxins. the cardiotoxins were subcloned in the expression vector pet 20b(+) and transformed in bl 21(de3) e. coli strain. the expressed protein was isolated from the inclusion bodies of e. coli and purified by reversed phase high performance liqu ... | 1996 | 8619792 |
| liver class-i alcohol dehydrogenase isozyme relationships and constant patterns in a variable basic structure. distinctions from characterization of an ethanol dehydrogenase in cobra, naja naja. | the major ethanol dehydrogenase of cobra liver was characterized in order to clarify isozyme relationships and functional motifs of the vertebrate enzyme. the cobra protein is a class-i form, most related to one of the isozyme subunits (the a form) in uromastix (lizard) liver. this positions the isozyme duplication and defines the main-line alternative. the new structure also allows extensive correlations with structure/function relationships for alcohol dehydrogenases in general, of which 38 an ... | 1996 | 8612631 |
| cloning, direct expression, and purification of a snake venom cardiotoxin in escherichia coli. | the cardiotoxin analogue iii (ctx iii), isolated from the taiwan cobra (naja naja atra) venom, is a sixty-amino acid, all beta-sheet protein. we report the direct expression of ctx iii from its synthetic gene as inclusion bodies in escherichia coli. the yield of the expressed protein is about 40 mg/liter of the culture. ctx iii trapped as inclusion bodies is dissolved and refolded by the slow refolding technique. the refolded protein is purified by reverse phase high performance liquid chromatog ... | 1996 | 8605008 |
| nerve growth factor from the venom of the chinese cobra naja naja atra: purification and description of non-neuronal activities. | nerve growth factor (ngf) was separated from crude naja naja atra venom by using weak cation-exchange chromatography, followed by reversed-phase liquid chromatography. the yield of the purification was 0.2-0.5% (w/w). the mol. wt was determined to be 13,600 and the protein still induced the typical fibre outgrowth of cultured pc-12 cells in a concentration range of 5-10 ng/ml. beside this neuronal effect we demonstrated non-neuronal effects of cobra venom ngf, such as induction of plasma extrava ... | 1995 | 8599177 |
| pefabloc, 4-[2-aminoethyl]benzenesulfonyl fluoride, is a new, potent nontoxic and irreversible inhibitor of paf-degrading acetylhydrolase. | we report here that 4-[2-aminoethyl]benzenesulfonyl fluoride (pefabloc sc, pefabloc), a new irreversible serine proteinase inhibitor, efficiently inhibits both human and rat platelet activating factor (paf)-degrading acetylhydrolase (acetylhydrolase). indeed, low concentrations of pefabloc (0.1 mm) rapidly and totally inactivate both human plasma-, vldl-, idl-, ldl- and hdl-associated acetylhydrolase, and in addition, acetylhydrolase synthesized and released by human adherent monocytes in cultur ... | 1996 | 8597590 |
| purification and characterization of a novel phospholipase a2 from king cobra (ophiophagus hannah) venom. | a novel phospholipase a2, designated as oh-de-2, was isolated from the venom of ophiophagus hannah (king cobra) by successive chromatography on sp-sephadex c-25, de-52, and q-sepharose columns. oh-de-2 with pi 5.1 showed an apparent molecular weight of 14 kd as revealed by sds-page and gel filtration. the amino acid sequence was homologous with those of pla2s from elapidae venoms. oh-de-2 was effectively inactivated by p-bromophenacyl bromide, indicating that the conserved his-48 is essential fo ... | 1995 | 8593185 |
| effects of marine 2-polyprenyl-1,4-hydroquinones on phospholipase a2 activity and some inflammatory responses. | three 2-polyprenyl-1,4-hydroquinone derivatives (2-heptaprenyl-1,4-hydroquinone: is1, 2-octaprenyl-1,4-hydroquinone: is2 and 2-[24-hydroxy]-octaprenyl-1,4-hydroquinone: is3) isolated from the mediterranean sponge ircinia spinosula, were evaluated for effects on phospholipase a2 activity of different origin (naja naja venom, human recombinant synovial fluid and bee venom), as well as on human neutrophil function and mouse ear oedema induced by 12-o-tetradecanoylphorbol 13-acetate (tpa). is1 inter ... | 1995 | 8575515 |
| evidence of the coevolution of a snake toxin and its endogenous antitoxin cloning, sequence and expression of a serum albumin cdna of the chinese cobra. | a full-length cdna of the serum albumin (csa) of the cobra (naja naja kaouthia) was cloned from a lambda gt 11 library. it encodes a mature protein of 614 amino-acid residues homologous to the precursor of mammalian serum albumins. the 1 degree and 2 degrees structures of the csa resemble those of the human variety. the putative toxin binding sites are mainly located in the subdomains iia and iiia. the relation between structural homology and function of the serum albumins (sa) is discussed. an ... | 1995 | 8561913 |
| [refinement of the spatial structure of neurotoxin ii from naja naja oxiana venom]. | a set of 19 conformations of the neurotoxin ii from naja naja oxiana was determined by conformational energy minimization using constraints derived from experimental 1h nmr data. the pairwise average root-mean-square deviations were 0.86 a for the backbone heavy atoms and 1.48 a for all heavy atoms of these conformations. a model of the neurotoxin ii dimer is proposed to account for the relatively slow deuterium exchange rates of the val45 and leu51 amide protons, which are exposed to the solven ... | 1995 | 8540898 |
| structural importance of the cis-5 ethylenic bond in the endogenous desaturation product of dietary elaidic acid, cis-5,trans-9 18:2 acid, for the acylation of rat mitochondria phosphatidylinositol. | when rats were fed elaidic (trans-9 18:1) acid at a high load in diets that were otherwise marginally or almost completely deficient in linoleic (cis-9,cis-12 18:2) acid, elaidic acid was desaturated to cis-5,trans-9 18:2 acid. this polymethylene-interrupted acid was then incorporated into most phospholipids from rat mitochondria, cardiolipin being an exception. its level of esterification in phospholipids followed the increasing order: phosphatidylethanolamine < phosphatidylcholine < phosphatid ... | 1995 | 8538375 |
| bovine serum albumin does not completely block synaptosomal cholinergic activities of presynaptically acting snake venom phospholipase a2 enzymes. | bovine serum albumin (bsa), which binds fatty acids, was used to test the contribution of free fatty acid to the presynaptic toxicity of phospholipase a2 (pla2) enzymes. the effects of bsa on inhibition of [14c]choline uptake and stimulation of [14c]acetylcholine (ach) release in synaptosomes by pla2 enzymes that do not have a predominant presynaptic action at the neuromuscular junction (ps-) were compared with those on the cholinergic actions of pla2 enzymes that do have a predominant presynapt ... | 1995 | 8533139 |
| recombinant human type ii phospholipase a2 lacks edema producing activity in rat. | the rat paw edema-inducing, acute inflammatory activity of four snake venom phospholipase a2s (pla2) (naja naja, naja mocambique mocambique, crotalus atrox and recombinant naja naja naja) and of recombinant human type ii pla2 (rh-pla2) found in rheumatoid synovial fluid, were compared after a bolus subplantar injection. the snake venom-derived pla2s, including the recombinant naja naja naja, were potent inducers of paw edema. on the other hand, when given in similar amounts (protein and/or enzym ... | 1993 | 8519280 |
| two-dimensional 1h-nmr study of the spatial structure of neurotoxin ii from naja naja oxiana. | the spatial structure of neurotoxin ii from the venom of the central asian cobra naja naja oxiana was determined by two-dimensional 1h-nmr techniques and computational analysis. nearly complete proton resonance assignments for 61 amino acid residues have been made using two-dimensional (2d) homonuclear total correlated spectroscopy, 2d homonuclear double-quantum-filtered correlated spectroscopy and 2d homonuclear noe spectroscopy (noesy) experiments. the cross-peak volumes in noesy spectra spin- ... | 1993 | 8504813 |
| interaction of phospholipase a2 with thioether amide containing phospholipid analogues. | transferred noe experiments have been carried out on cobra venom (naja naja naja) phospholipase a2 (pla2) with substrate analogues which serve as potent inhibitors. 1-(hexylthio)-2-(hexanoylamino)-1,2-dideoxy-sn-glycero-3-pho sphoethanolamine (pe) and the corresponding phosphocholine analogue (pc) are water-soluble, short-chain, nonhydrolyzable substrate analogues which bind tightly to the enzyme. because they are small compounds and monomeric in solution, noes develop inefficiently in the absen ... | 1993 | 8494876 |
| pharmacokinetics of cytotoxin from chinese cobra (naja naja atra) venom. | the pharmacokinetics of cytotoxin from chinese cobra (naja naja atra) venom was studied in rabbits after i.v. and i.m. injection of 0.2 and 0.5 mg.kg-1, respectively. the plasma levels of the cytotoxin were analysed by a biotin-avidin enzyme-linked immunosorbent assay. the plasma concentration-time course after i.v. administration fitted a two-compartment open model. the half-life (mean +/- s.d.) of the alpha-phase was 5.8 +/- 0.6 min and that of the beta-phase 3.5 +/- 0.2 hr. apparent volume of ... | 1993 | 8470137 |
| three-dimensional structure of neurotoxin-1 from naja naja oxiana venom at 1.9 a resolution. | neurotoxin-1 from naja naja oxiana venom (ntx-1) has been crystallized by vapor diffusion in sitting drops. the crystals have cell dimensions of a = 25.2 a, b = 75.6 a, c = 35.9 a, and are in space group p2(1)2(1)2(1). three-dimensional data to 1.9 a have been recorded by a syntex p2(1) automatic diffractometer. the atomic structure of the toxin has been determined by molecular replacement using the alpha-cobratoxin (alpha-ctx) as the search model. the position of 534 non-hydrogen protein atoms ... | 1993 | 8458425 |
| hydrolysis of micellar diheptanoylphosphatidylcholine catalyzed by bovine pancreatic phospholipase a2: kinetic characterization of group i and ii enzymes. | initial velocity data for the hydrolysis of micellar 1,2-diheptanoyl-sn-glycero-3-phosphorylcholine (dic7pc) catalyzed by bovine pancreatic pla2 (group i) were analyzed using the michaelis-menten equation. the km value for the micellar substrate was found to be independent of ca2+ concentration, as was the km value for the monodispersed substrate. the ph dependence curve of km in the presence of saturating amounts of ca2+ showed two transitions reflecting large pk shifts of two ionizable groups ... | 1993 | 8454568 |
| snake venom cardiotoxin can rapidly induce actin polymerization in intact platelets. | the action of taiwan cobra (naja naja atra) venom cardiotoxin on rabbit platelets at 37 degrees c was characterized by observing cytoskeletal alterations and cell lysis. at a concentration of 21.4 microm the toxin produced no cell lysis within 30 s, and less than 5% of the total lactate dehydrogenase activity of intact cells was detected in the suspending medium after the interaction had proceeded for 3 min. the extent of cell lysis was proportional to toxin concentration and interaction time. b ... | 1993 | 8452550 |
| molecular cloning of a cardiotoxin structural gene from malayan spitting cobra (naja naja sputatrix). | the structural gene and cdna encoding cardiotoxin in naja naja sputatrix have been cloned and characterized with a view to study the gene protein relationships and also to produce pure protein in large amounts. using the polymerase chain reaction on the total rna isolated from the venom glands, the structural gene (180 bp) has been synthesized and expressed in escherichia coli to produce a fusion protein with beta-galactosidase. immunoblotting using polyclonal antibodies raised against the total ... | 1993 | 8446963 |
| species difference in modulation of calcium release by naja naja kaouthia snake venom cardiotoxin in terminal cisternae from human and equine skeletal muscle. | the modulation of ca2+ release by a cardiotoxin (ctx) from naja naja kaouthia snake venom was examined in terminal cisternae-containing fractions from equine and human skeletal muscle. pretreatment with ctx (10 microm) decreased by 27% (human muscle), or had no effect on (equine muscle), the threshold of ca(2+)-induced ca2+ release. if terminal cisternae fractions were first preloaded with ca2+ to greater than 65% of the threshold of ca(2+)-induced ca2+ release and then ctx added, an immediate a ... | 1993 | 8446962 |
| crystal structure of phospholipase a2 from indian cobra reveals a trimeric association. | phospholipase a2 (pla2) from indian cobra venom (naja naja naja) was crystallized from ethanol in space group p4(3)2(1)2 in the presence of ca2+. the x-ray crystal structure was determined to 2.3-a resolution by molecular replacement techniques using a theoretical model constructed from homologous segments of the bovine pancreatic, porcine pancreatic, and rattlesnake venom crystal structures. the structure was refined to an r value of 0.174 for 17,542 reflections between 6.0- and 2.3-a resolutio ... | 1993 | 8419939 |
| the role of phospholipase a2 in interleukin-1 alpha-mediated inhibition of mineralization of the osteoid formed by fetal rat calvaria cells in vitro. | interleukin-1 (il-1) may be an important mediator of bone remodeling, since it is a potent stimulator of bone resorption and has biphasic effects on bone formation. continuous exposure of fetal rat calvaria (rc) cells to il-1 alpha or il-1 beta results in a dose-dependent inhibition of both bone nodule formation and mineralization of the organic matrix. in this study, the effects of recombinant human il-1 alpha on the mineralization process were examined by the addition of il-1 alpha late in the ... | 1993 | 8418103 |
| identification of functional involvement of tryptophan residues in phospholipase a2 from naja naja atra (taiwan cobra) snake venom. | phospholipase a2 (pla2) from naja naja atra snake venom was subjected to trp modification with 2-nitrophenylsulfenyl chloride (nps-cl), and six derivatives were separated by hplc. the results of amino-acid analysis and sequence determination revealed that trp-18, trp-19 and trp-61 were modified by nps-cl. the order of accessibilities of the three trp residues for nps-cl was trp-18 > trp-19 > trp-61. sulfenylation of trp-18 caused a 92% drop in enzymatic activity. modification of trp-19 and trp-6 ... | 1993 | 8399382 |
| effect of polar head groups on the interactions of phospholipase a2 with phosphonate transition-state analogues. | several new phosphonate-containing phospholipid analogues were synthesized as inhibitors of cobra venom (naja naja naja) phospholipase a2. these phospholipid analogues contained a novel thioether at the sn-1 position, a tetrahedral phosphonate moiety in place of the scissile ester bond at the sn-2 position, and several different polar head groups, including phosphocholine, phospho(n,n-dimethylethanolamine), phospho(n-methylethanolamine), and phosphoethanolamine. the affinities of these analogues ... | 1993 | 8399145 |
| a continuous fluorescence displacement assay for phospholipase a2 using albumin and medium chain phospholipid substrates. | a continuous fluorescence assay for phospholipase a2 is described which involves the displacement of the highly fluorescent fatty-acid probe 11-(dansylamino) undecanoic acid from albumin by decanoic acid released as a result of phospholipase a2-catalyzed hydrolysis of didecanoyl-phosphatidylcholine. using the phospholipase a2 from naja naja, this assay will detect activity from 1 ng of pure enzyme and a linear response in terms of fluorescence change with time is observed up to about 50 ng of en ... | 1993 | 8368517 |
| studies on the cobra neurotoxin inhibiting activity in an extract of curcuma sp. (zingiberaceae) rhizome. | a study was carried on the mode of action and some properties of a cobra neurotoxin inhibitor found in the extract of curcuma sp. (zingiberaceae). when the principal postsynaptic neurotoxin (stx) of the thai cobra (naja naja siamensis) was mixed with an aqueous extract of curcuma sp. rhizome, the stx was inactivated as tested in mice or in vitro using a rat hemidiaphragm preparation. the 'neurotoxin inhibitor' ('ntxi') was found only in the water insoluble fraction of the rhizome extract. using ... | 1993 | 8362293 |
| influence of chemistry in immobilization of cobra venom phospholipase a2: implications as to mechanism. | phospholipase a2 from naja naja kaouthia venom was covalently coupled onto agarose beads using two different chemistries. the effect of micellar competitive inhibitors in the coupling media was evaluated. enzyme bound to n-hydroxysuccinimide-activated agarose, which is reactive primarily toward epsilon-amino groups, had 20% activity retention against micellar diheptanoylphosphatidylcholine (dic7-pc). enzyme bound through carboxylic groups, using a modification of the carbodiimide method, had 50% ... | 1993 | 8347610 |
| solution structure of cardiotoxin v from naja naja atra. | cardiotoxins are small proteins that are found in the venoms of snakes from the elapidae family. these toxins are known to bind to and disrupt the organization, integrity, and function of the cell membrane. most of the well-studied cardiotoxins cause depolarization of membrane potentials and/or lysis of red cells. in contrast, ctx v from naja naja atra displays poor hemolytic activity but is proficient at inducing aggregation and fusion of sphingomyelin vesicles [chien et al. (1991) j. biol. che ... | 1993 | 8347605 |
| purification, characterization and binding interactions of the chinese-cobra (naja naja atra) serum antitoxic protein csap. | the characterization of the single-chain protein in chinese-cobra (naja naja atra) blood serum, which yields strong specific protection against the venom of the same snake, is reported. the protein, csap (cobra serum antitoxic protein), was purified to electrophoretic homogeneity. over the ph range 5-9 it formed stable complexes with the neuro- and the cardio-toxin of the snake. the molecular size of the csap was estimated to be 70.3 +/- 0.3 kda. tryptic hydrolysis of csap yielded several peptid ... | 1993 | 8343135 |
| cardiotoxin 1 from cobra (naja naja atra) venom causes necrosis of skeletal muscle in vivo. | cardiotoxin 1 from cobra (naja naja atra) venom was tested for its ability to cause necrosis of skeletal muscle cells after i.m. injection into mice. light and electron microscopic examination of tissue indicated that the toxin caused necrosis of skeletal muscle as early as 30 min after injection. the plasma membranes of affected cells were ruptured in the area of delta lesions, and the myofibrils were condensed into dense clumps alternating with clear areas containing elements of the sarcotubul ... | 1993 | 8342169 |
| probing the functional sites in naja naja atra (taiwan cobra) cardiotoxin iii with monoclonal antibody. | one monoclonal antibody (mab) against naja naja atra cardiotoxin iii was prepared by using the hybridoma technique. the cytotoxic activity of cardiotoxin iii which inhibited human lymphocyte proliferation was effectively neutralized by the mab at a molar ratio of antibody to toxin of 1:2. on the contrary, the mab did not exert a significant inhibition on the hemolytic activity of cardiotoxin iii. these results suggest that the functional site responsible for the cytotoxicity might be different f ... | 1993 | 8330009 |
| cardiotoxin iii from the taiwan cobra (naja naja atra). determination of structure in solution and comparison with short neurotoxins. | the structure in solution of cardiotoxin iii, a membrane toxin purified from the venom of the taiwan cobra, naja naja atra, is reported. sequence-specific assignment of 1h-nmr lines was completed and the nmr data show the presence of a triple and a double-stranded antiparallel beta-sheet. many noe cross peaks identified in noesy spectra were applied as distance constraints based on a hybrid distance geometry/dynamical simulated annealing technique; 20 structures were found within a single family ... | 1994 | 8308891 |
| interaction of protein ligands with receptor fragments. on the residues of curaremimetic toxins that recognize fragments 128-142 and 185-199 of the alpha-subunit of the nicotinic acetylcholine receptor. | using a solid-phase assay, we found that 3h-labeled alpha cobtx from naja naja siamensis, a long-chain curaremimetic toxin, and 3h-labelled toxin alpha from naja nigricollis, a short-chain toxin both bind specifically but with substantially different affinities (kd = 4 x 10(-7) m and 50 x 10(-6) m) to fragment 185-199 (t alpha 185-199) of the alpha-subunit of the acetylcholine receptor (acchor) from torpedo marmorata. then we show that monoderivatizations of residues common to both long-chain an ... | 1994 | 8307203 |
| characteristics of the peptidase activity contained in taiwan cobra (naja naja atra) venom. | cobra venoms (naja species) contain a little-understood peptidase activity which shows specificity towards small peptides containing glycine and non-polar aromatic/aliphatic residues. we have examined the ability of whole cobra venom to degrade several types of peptide with emphasis on the action of taiwan cobra (naja naja atra) venom on l-alanylglycylglycine and glycylglycyl-l-phenylalanine. these are competing substrates, and it proved possible to generate inhibitors of the degradation of glyc ... | 1993 | 8303723 |
| effects of different antagonists on depolarization of cultured chick myotubes by cobra venom cardiotoxins and pyrularia thionin from the plant pyrularia pubera. | cardiotoxins (3.12 and 3.12.1) purified from cobra venom (naja naja siamensis) are basic single-chain polypeptides of about 60 residues. although they depolarize nerve and muscle cells and have cytolytic effects, their mechanism of action is still unknown. pyrularia thionin (p-thionin) isolated from nuts of the parasitic plant pyrularia pubera is a strongly basic, single-chain polypeptide containing 47 residues. it is known to be haemolytic and cytotoxic, and to depolarize muscle cells, but its ... | 1993 | 8303717 |
| vasoactive intestinal peptide and helodermin inhibit phospholipase a2 activity in vitro. | we recently reported that the widely distributed neuropeptide vasoactive intestinal peptide (vip) reduces inflammatory lung injury due to a variety of agents and inhibits the associated generation of cyclo-oxygenase and lipoxygenase products. we therefore investigated whether vip may inhibit phospholipase a2 activity, thus reducing the release of arachidonic acid, the common precursor of all eicosanoids. vip dose-dependently inhibited pla2 of porcine pancreas and of naja naja venom, as assessed ... | 1993 | 8278623 |
| differential effects of mandevilla velutina compounds on paw oedema induced by phospholipase a2 and phospholipase c. | this study compares the effect of mandevilla velutina compounds with some anti-inflammatory drugs against phospholipase a2- and phospholipase c-induced rat hindpaw oedema. injection of phospholipase a2 (naja naja, 2.5-20 u/paw) and phospholipase c (clostridium perfringens, 0.03-0.05 u/paw) caused a dose-and-time-related increase in paw oedema. compounds mv 8608 (55 mumol/kg) and mv 8612 (32 mumol/kg, i.p.) inhibited phospholipase a2-induced paw oedema without interfering with phospholipase c-ind ... | 1993 | 8276072 |
| chemical modification of amino groups in cardiotoxin iii from taiwan cobra naja naja atra) venom. | cardiotoxin iii (ctx iii), a major cardiotoxin analogue isolated from the taiwan cobra (naja naja atra) venom was modified, either with trinitrobenzene sulfonate (tnbs) or 4-chloro-3,5-dinitrobenzoate (cdnb). under the conditions of limited reagent availability, three mono-tnp derivatives modified at lys-5, 12, or 44, and three mono-cdnp derivatives at lys-12, 23, or 44 were isolated, respectively. the biological activities of ctx iii were more or less affected after each of these reactive amino ... | 1993 | 8260941 |
| [purification and anticancer activity of cytotoxin-14 from venom of naja naja atra]. | ion-chromatography of lyophilized cobra (naja naja atra) venom on sp-sephadex c-50 yielded 14 fractions, of which 7, 8, 9, and 10 possessed neurotoxic actions and 11, 12, 13, and 14 had cytotoxic activities. chromatography of fraction 14 on sp-sephadex c-25 gave cytotoxin-14. it was homogeneous on polyacrylamide gel electrophoresis with m = 7448 da. it was a typical cytotoxin without phospholipase a2 activity and had a selective cytotoxic action on human cancer cell lines. | 1993 | 8237412 |
| oedema formation and degranulation of mast cells by phospholipase a2 purified from porcine pancreas and snake venoms. | phospholipase a2 is ubiquitous in nature, with the highest concentrations occurring in pancreatic juice and in the venom of snakes. local oedema formation is a common feature of the effects caused by snakebite, and indicates an increase in vascular permeability that could be produced by lipid mediators such as lysophospholipids, eicosanoids or paf release by the enzymatic activity of pla2. desalted porcine pancreatic pla2 exhibited strong oedema-inducing activity in a similar form to pla2 venom ... | 1993 | 8212047 |
| acetylcholine receptor binding characteristics of snake and cone snail venom postsynaptic neurotoxins: further studies with a non-radioactive assay. | the binding of postsynaptic neurotoxins from snake and marine cone snail (conus sp.) venoms to nicotinic acetylcholine receptor (achr) was investigated with an elisa-based, non-radioactive assay. three snake postsynaptic toxins from the long-chain group (naja naja kaouthia cobratoxin, naja oxiana neurotoxin i, bungarus multicinctus alpha-bungarotoxin) and short-chain group (naja naja atra cobrotoxin, naja oxiana neurotoxin ii, and laticauda semifasciata erabutoxin b) were studied. both types of ... | 1993 | 8212028 |
| sequence characterization of cardiotoxins from taiwan cobra: isolation of a new isoform. | cardiotoxins (or called cytotoxins) are a group of very basic polypeptides present in some snake venoms, which are especially abundant in formosan cobras. several cardiotoxins with distinct pharmacological and biochemical properties were isolated and purified from the taiwan cobra venom (naja naja atra) by employing sequentially preparative-scale cation-exchange chromatography on tsk cm-650 coupled with the improved separation of toxin components on reversed-phase hplc based on their hydrophobic ... | 1993 | 8193587 |
| effects of flavonoids on naja naja and human recombinant synovial phospholipases a2 and inflammatory responses in mice. | six flavonoid derivatives were tested for their influence on naja naja and human recombinant synovial phospholipase a2. they showed a selectivity for the last enzyme with ic50 = 14.3, 17.6, 12.2 and 28.2 microm for quercetagetin, kaempferol-3-o-galactoside, scutellarein and scutellarein-7-o-glucuronide, respectively, while reduced effects were observed for hispidulin and hibifolin. after topical application all the flavonoids inhibited 12-o-tetradecanoylphorbol-13-acetate-induced ear oedema in m ... | 1994 | 8190018 |
| two distinct types of cardiotoxin as revealed by the structure and activity relationship of their interaction with zwitterionic phospholipid dispersions. | cardiotoxins (ctxs) are a group of homologous proteins found in cobra snake venom and consist of 60-62 amino acid residues. although ctxs are known to consist of three extended beta-sheet loops similar to neurotoxins, the target and interaction of ctxs with membranes unlike those of neurotoxins are not well understood. herein, we report comparative studies of 10 ctxs purified from taiwan cobra (naja naja atra) and mozambique spitting cobra (naja mossambica mossambica) snake venoms with respect t ... | 1994 | 8182052 |
| isolation and characterization of a phospholipase a2 inhibitor from the blood plasma of the thailand cobra naja naja kaouthia. | a phospholipase a2 (pla2) inhibitory protein was purified from the blood plasma of the thailand cobra naja naja kaouthia by sequential chromatography on sephadex g-200, deae affi-gel blue, and protein-pak g-butyl columns. the purified inhibitor was a glycoprotein with an apparent molecular mass of about 90 kda and contained 25- and 31-kda subunits with a molar ratio of 1:2. the 31-kda subunit contained a glycosidic chain and the molecular mass was reduced to 28 kda by n-glycosidase f treatment. ... | 1994 | 8179612 |
| micellar bolaform and omega-carboxylate phosphatidylcholines as substrates for phospholipases. | a series of mixed-chain diacyl-pcs which contain an omega-cooh on the sn-2 chain [1-cx-2-cy-(cooh)-pc] and bolaform (1-cx-2,2'-cy-1'-cx-pc) phosphatidylcholines were synthesized and examined as substrates for phospholipase a2 (naja naja naja) and c (bacillus cereus). there is very little detectable phospholipase a2 activity toward pure micellar 1-acyl-2-acyl-(omega-cooh) species. in addition, when these same omega-cooh species are present at concentrations above their cmcs, they are potent inhib ... | 1994 | 8172875 |
| a sensitive fluorogenic enzyme linked immunosorbent assay for the detection of vipera russelli venom. | a highly sensitive fluorogenic enzyme-linked immunosorbent assay (felisa) has been adapted for the detection of vipera russelli venom. the assay sensitivity was observed to be 0.1 pg/ml (1 x 10(-13) g/ml). venoms from snakes of the vipera group exhibited a high degree of cross-reactivity when tested with the antibody raised against v. russelli venom. with the exception of venom from naja naja, all the tested venoms from unrelated families also showed cross-reactivity. this procedure is useful fo ... | 1993 | 8167946 |
| structural determinants of the intrinsic fluorescence emission in notexin and phospholipase a2 enzymes. | fluorescence measurements of the homologous proteins, notexin and pla2 enzymes from naja naja atra, naja nigricollis, and hemachatus haemachatus venoms, showed that the wave-length of maximum emission and the quantum yield of their intrinsic fluorescence emission spectra were different. to verify the factors which affected their fluorescence characteristics, the dynamics of tryptophan residues in those homologous proteins were studied by quenching with acrylamide, iodide, and cesium. the degrees ... | 1993 | 8142000 |
| inhibition of trimeresurus flavoviridis phospholipase a2 by lung surfactant protein a (sp-a). | a marked sequence homology has been noted between lung surfactant protein a (sp-a) and an inhibitor of phospholipase a2 (pla2) isolated from the serum of trimeresurus flavoviridis (habu snake). this study evaluated the effect of sp-a on pla2 activity from several sources. sp-a was isolated from bovine or rat lung surfactant by extraction with 1-butanol and octyl beta-d-glucopyranoside. the addition of sp-a produced a concentration-dependent inhibition of t. flavoviridis pla2 that indicated non-c ... | 1994 | 8130257 |
| both neurotoxin ii from venom of naja naja oxiana and its endogenous analogue induce apoptosis in tumor cells. | both neurotoxin ii (nt ii from venom of naja naja oxiana) and 20-30 kda proteins partially purified from pig brain (ntlm) cross-reacting with antibodies to nt ii were cytotoxic for l929 and k562 tumor cells at concentrations of 10(-6)-10(-8) m. modification of cys residues significantly reduced cytotoxicity of nt ii. both nt2 and ntlm induced apoptosis in l929 and k562 cells. | 1994 | 8119402 |
| interactions of n-terminal fragments of groups i and ii phospholipases a2 with phospholipid bilayers and their surface recognition properties. | in order to elucidate the roles of the n-terminal segments of groups i and ii phospholipases a2 (pla2s) which have been known to have alpha-helical structure and have been assumed to be involved in the water/lipid interface recognition site, the peptides corresponding to the n-terminal moieties of group i pla2 (naja naja atra) and group ii pla2s (trimeresurus flavoviridis and crotalus atrox) were synthesized and their interactions with model membranes were studied. circular dichroism spectra sho ... | 1994 | 8117749 |
| cardiotoxin ii from taiwan cobra venom, naja naja atra. structure in solution and comparison among homologous cardiotoxins. | the three-dimensional structure in solution of cardiotoxin ii, a membrane toxin from the venom of taiwan cobra, naja naja atra, was determined using 1h nuclear magnetic resonance spectroscopy and molecular modeling based on the hybrid distance geometry/dynamic simulated annealing technique. a complete sequence-specific proton assignment was obtained, and the secondary structures of the protein were determined from information on nuclear overhauser effect connectivities, coupling constants, and h ... | 1994 | 8089116 |
| effects of systemic complement activation on renal circulation of rats. | in a variety of immunopathological diseases activation of the complement cascade occurs either systemically or localized in the kidney. to elucidate the functional impact of complement activation upon the renal microcirculation, we administered cobra venom factor of naja naja kaouthia (cvf) i.v. into thiobarbital anaesthetized female rats. cvf is a potent activator of the alternative pathway of complement by forming the c3-convertase cvf, bb which cannot be downregulated by the natural inhibitor ... | 1994 | 8088308 |
| groups i, ii and iii extracellular phospholipases a2: selective inhibition of group ii enzymes by indomethacin but not other nsaids. | the three types (groups i, ii and iii) of stable extracellular 14 kda phospholipase a2 enzymes differ in their primary amino acid sequences and their properties. it may thus be possible to design low-molecular weight inhibitors targeted to the secretory form of mammalian pla2. this enzyme has been implicated in inflammatory disorders. we have studied the inhibition of four distinct pla2 enzymes by a range of nsaids, using 3h-oleate release from prelabelled membranes of e. coli for assay. the enz ... | 1994 | 8079814 |
| a comparative study of three vehicles on antibody responses against elapid snake neurotoxin immunogens. | a study was undertaken to compare the effects of three vehicles (incomplete freund's adjuvant, ifa; bentonite and squalene/arlacel a) on the antibody responses to various elapid neurotoxin immunogens. three neurotoxin immunogens were prepared using purified principal postsynaptic neurotoxin(s) of naja naja siamensis (nns), ophiophagus hannah (oh) and bungarus fasciatus (bf). glutaraldehyde (ga) or a carbodiimide (ecdi) was used as a coupling agent while diphtheria toxoid (dt) was used as a prote ... | 1994 | 8079368 |
| comparison of refolding patterns of erabutoxin b and cardiotoxin 3.10.2 from snake venom. | the refolding patterns of erabutoxin b (a neurotoxin) and cardiotoxin 3.10.2 (from naja naja siamensis venom) have been studied by reducing both the proteins by treatment with reduced dithiothreitol followed by renaturation by treatment with oxidised dithiothreitol. isoelectric focusing of the samples trapped at varying time intervals during renaturation of the proteins reveals formation of intermediates in the folding pathway with cardiotoxin 3.10.2. having fewer intermediates than erabutoxin b ... | 1994 | 8076968 |
| a comparison of ovine and equine antivenoms. | commercial antivenoms produced in horses were compared with monospecific antivenoms raised in sheep against crotalus durissus terrificus, crotalus atrox, crotalus adamanteus, micrurus fulvius fulvius, naja naja, naja kaouthia, echis ocellatus, vipera lebetina deserti, vipera berus berus and vipera ammodytes ammodytes venom. antibodies raised by immunizing sheep with c. d. terrificus venom were more effective than their equine counterparts in preventing lethal toxicity in mice (ed50), in inhibiti ... | 1994 | 8052997 |
| functional properties of human factor va lacking the asp683-arg709 domain of the heavy chain. | a protease purified from the venom of the elapid snake naja naja oxiana converts human blood coagulation factor va into a molecule (factor vano) with greatly reduced cofactor activity. polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate revealed that the venom protease cleaved a small peptide from the heavy chain of factor va and reduced the apparent m(r) from 105,000 to 101,000. this peptide was isolated by high performance liquid chromatography on a reversed-phase colu ... | 1994 | 8051166 |
| structure of cobra cardiotoxin ctx i as derived from nuclear magnetic resonance spectroscopy and distance geometry calculations. | the structure of cardiotoxin ctx i from naja naja atra has been investigated by nmr spectroscopy. sequence specific resonance assignments have been obtained for all backbone protons as well as for most side-chain protons. distance geometry calculations were carried out using a metric matrix dg program. a total of 715 noe constraints, 27 phi angle constraints and a list of the hydrogen bond donors were used for the metric matrix dg calculations and refinement. the average pairwise r.m.s.d. of the ... | 1994 | 8046750 |
| zinc and barium inhibit the phospholipase a2 from naja naja atra by different mechanisms. | the mode of inhibition of the phospholipase a2 (pla2) enzyme from the chinese cobra (naja naja atra) by zn2+ is qualitatively different from inhibition by ba2+. inhibition by ba2+ shows the kinetic characteristics of a conventional competitive inhibitor acting to displace ca2+ from a single essential site, but zn2+ has the paradoxical property of being more inhibitory at high than at low ca2+ concentration. kinetic analysis of the ca(2+)-dependence of enzymic activity shows a bimodal response, i ... | 1994 | 8042995 |
| the use of the chick biventer cervicis preparation to assess the protective activity of six international reference antivenoms on the neuromuscular effects of snake venoms in vitro. | the protective activity of some antivenoms on the neuromuscular activity in vitro of six snake venoms was established in order to test the feasibility of using a simple isolated nerve-muscle preparation to compare different antivenoms. six venoms designated as international reference venoms by the world health organization (who) were used: echis carinatus (iran), echis carinatus (mali), naja naja kaouthia, notechis scutatus, trimeresurus flavoviridis, and vipera russelli (thailand). the chick bi ... | 1994 | 8016849 |
| screening of snake venoms for neurotoxic and myotoxic effects using simple in vitro preparations from rodents and chicks. | eight snake venoms designated by the who as international reference venoms, and one additional venom were assessed for neurotoxic and myotoxic effects in vitro using the chick biventer cervicis and the rat and mouse phrenic nerve-diaphragm preparations. the objective was to determine whether any of the preparations could be used to detect evidence of neurotoxic or myotoxic activity prior to a more detailed examination. bungarus multicinctus venom at concentrations above 1 microgram ml-1 selectiv ... | 1994 | 8016848 |
| [distribution of 131i-cytotoxin 14 from naja naja atra venom in rats]. | cytotoxin 14 (ct14) from naja naja atra venom was labelled with 131i by chloramine-t method and its tissue distribution was studied in rats. the highest concentration of the cytotoxin was found in kidney, 5979 dpm per mg weight, 14 times more than that of the control animals, at 0.5 h after i.v. injection and high concentrations were found in liver, spleen, pancreas, and adrenal. ct14 was also found in brain at 2 h after injection, 50 dpm per mg weight, 3 times more than that of the control. | 1994 | 8010097 |
| effects of direct lytic factors from southern chinese cobra venom on ca2+ movement in rabbit aorta strip. | the purified direct lytic factors (dlf) from southern chinese cobra (naja naja atra) venom induced a contractile response in ca(2+)-free krebs' solution and a further increase in the tension following a subsequent addition of ca2+ into bath. after depletion of intracellular ca2+ pool by phenylephrine, dlf failed to induce any contractile response. in 45ca2+ experiments, dlf increased both 45ca2+ release and 45ca2+ influx. procaine 2 mmol.l-1 decreased the dlf induced 45ca2+ release and 45ca2+ in ... | 1993 | 8010046 |
| the two subunits of a phospholipase a2 inhibitor from the plasma of thailand cobra having structural similarity to urokinase-type plasminogen activator receptor and ly-6 related proteins. | amino acid sequences of the two subunits (31-kda and 25-kda subunits) of a phospholipase a2 (pla2) inhibitory protein, purified from the blood plasma of thailand cobra naja naja kaouthia, were determined by alignment of peptides obtained by lysyl endopeptidase, staphylococcal v8 protease and endoproteinase asp-n digestions. the respective subunits were composed of 188 and 185 amino acid residues, and the former contained one asparagine-linked sugar chain at the position 157. there was 29% identi ... | 1994 | 7980598 |
| a study on the functional subunits of phospholipases a2 by enzyme immobilization. | pancreatic and venom phospholipases a2 have complex and distinct oligomerization behaviour. pancreatic enzymes are monomeric in solution, but their quaternary structure at interfaces is unknown. on the other hand, certain crotalid venom phospholipases a2 are dimeric in solution, and different reports have proposed either the monomer or the dimer as the catalytically functional subunit. in this study, enzyme immobilization was used as a tool for determining the functional subunits of these enzyme ... | 1994 | 7980413 |
| characterization of monoclonal antibodies against naja naja oxiana neurotoxin i. | seven monoclonal antibodies (mabs) were developed against neurotoxin i (nt-1), a protein from central asian cobra (naja naja oxiana) venom which binds specifically to nicotinic acetylcholine receptor (achr). all of the mabs cross-reacted with another long-chain post-synaptic neurotoxin, bungarus multicinctus alpha-bungarotoxin (alpha-bt), but not naja naja kaouthia alpha-cobratoxin, in an enzyme-linked immunosorbent assay (e.l.i.s.a.). short-chain post-synaptic neurotoxins like naja naja atra co ... | 1994 | 7945236 |
| exposure of phosphatidylcholine and phosphatidylinositol in plasma membranes from rat brain synaptosomes treated with phospholipase a2 toxins (beta-bungarotoxin, notexin) and enzymes (naja nigricollis, naja naja atra). | phospholipase a2 (pla2) toxins act presynaptically to block acetylcholine release and are much more potent and specific in their actions than pla2 enzymes even though they have lower enzymatic activity. since their mechanism of action is not completely understood, it was of interest to examine the toxins' effects on phospholipid asymmetry as changes in asymmetry are associated with changes in membrane functioning. rat brain synaptosomes were treated with the pla2 toxins beta-bungarotoxin (beta-b ... | 1994 | 7940575 |
| the amino acid sequences of two postsynaptic neurotoxins isolated from malayan cobra (naja naja sputatrix) venom. | the complete amino acid sequences of two postsynaptic neurotoxins (toxin-3 and toxin-5) isolated from malayan cobra (naja naja sputatrix) venom were determined by direct automated edman degradation of peptides obtained from digests with various proteases. toxin-3 and toxin-5 are both short-chain neurotoxins and their amino acid sequences are highly homologous to naja naja atra and naja naja philippinensis neurotoxin, respectively. toxin-3 is unique in possessing aspartic acid (d) as the fifth re ... | 1994 | 7886703 |
| role of ca2+ in the binding of phospholipase a2 with a monomeric substrate and with its amide-type analog. | effects of ca2+ on the kinetic parameters for the hydrolysis of monodispersed 1,2-dihexanoyl-sn-glycero-3-phosphorylcholine (dic6pc), catalyzed by group i phospholipases a2 (pla2s) from pseudechis australis, naja naja atra, and bovine pancreas and by group ii enzymes from vipera russelli russelli, agkistrodon halys blomhoffii, and trimeresurus flavoviridis, were studied by the ph-stat assay method at 25 degrees c, ph 7.5-8.2, and an ionic strength of 0.1 or 0.2 in the absence or presence of an a ... | 1994 | 7883763 |
| protective effect of cobra venom factor on pulmonary injury induced by oleic acid. | the protective effect of cobra venom factor (cvf), separated from the venom of naja naja atra, on pulmonary injury induced by oleic acid was reported. the blood gas tensions, tidal volume, transthoracic pressure and pulmonary arterial pressure in anaesthetized dogs were continually monitored. the experimental results showed that cvf, given 20 h before the dosage depleting complements exceed 95%, significantly attenuated oleic acid-induced pulmonary dysfunction, including hypoxemia, increasing ve ... | 1994 | 7868302 |
| identification of 'molten globule'-like state in all beta-sheet protein. | the cardiotoxin analogue iii (ctx iii), isolated from the taiwan cobra venom (naja naja atra), is a sixty amino acid, all beta-sheet protein. the 2,2,2-trifluoro ethanol (tfe) induced unfolding of ctx iii is studied under acidic conditions (ph 2.5). using circular dichroism, 1-anilino-8-napthalene sulphonic acid binding and nmr experiments, it is shown that stable, partially structured state(s) ['molten globule'-like state] is formed between 50 and 80% tfe concentrations. the protein was found t ... | 1995 | 7864840 |
| [the characteristics of the binding of m-cholinergic blockers and beta-adrenoblockers by the brain synaptosomes of 15-day-old and adult rats]. | significant difference in values of basic parameters, bmax and kd which characterize binding of 3h-quinuclidynylbenzylate and 3h-dihydroalprenolol, specific blockers of m-cholino- and beta-adrenoreceptors, has been established for brain synaptosomes from 15-day and adult rats. it was shown that phospholipase a2 (1 microgram/ml), a membrane active component from the venom of the cobra naja naja oxiana, reduced bmax and kd for binding 3h-quinuclidynylbenzylate and 3h-dihydroalprenolol by synaptoso ... | 1994 | 7863744 |
| the three-dimensional nmr solution structure of alpha-cobratoxin at ph 7.5 and conformational differences with the nmr solution structure at ph 3.2. | the 3d solution structure of alpha-cobratoxin, a neurotoxin purified from the naja naja siamensis snake venom, has been determined by nuclear magnetic resonance spectroscopy, in conjunction with distance geometry and restrained molecular dynamics, at ph 7.5. a total of 490 distance restraints were obtained from noe intensities and 25 phi dihedral angle restraints deduced from j-coupling data. the generated structures are well defined with root mean square deviations from a geometrical mean struc ... | 1994 | 7848557 |
| [structure of peptide fragments of the complex (lys(abz)26) neurotoxin ii from naja naja oxiana cross-linked with the nicotinic acetylcholine receptor from torpedo californica]. | after irradiating the acetylcholine receptor complex with the title neurotoxin derivative, the labeled delta-subunit was separated by preparative sds-page, reduced-carboxymethylated and cleaved with lysc endoproteinase. one of the radioactive peptides isolated by hplc was further purified by electrophoresis in a tricin gel. edman degradation of the radioactive fractions yielded the sequence of the delta-subunit fragment starting from phe148. the aspn-cleavage of the radioactive peptide from the ... | 1994 | 7826405 |
| [ansa analysis. vi. activation, inhibition and interaction of proteases in enzyme mixtures]. | a new accurate method (ansa-analysis) is used for studying the interactions of proteases with their inhibitors or other proteases. the method is based on the cleavage by proteases of mixtures of competing chromogenic substrates containing aminonaphthalenesulfonamide (ansa) detectable groups. each substrate contained a specifically substituted ansa group which showed its specific retention time during chromatographic separation. for the analysis of blood coagulation, mixtures of blood-clotting fa ... | 1994 | 7819398 |
| sequence comparison and computer modelling of cardiotoxins and cobrotoxin isolated from taiwan cobra. | six cardiotoxins and one neurotoxin isolated and purified from the taiwan cobra venom (naja naja atra) possess distinct pharmacological and biochemical properties despite the existence of a grossly similar tertiary structure among these toxins, i. e., a core consisting of a series of short loops and four disulfide bridges. a systematic structure comparison of these major toxin isoforms was made by the secondary-structure predictions together with computer model-building based on the primary sequ ... | 1995 | 7818523 |
| chemical modification of lys-6 in taiwan cobra phospholipase a2 with 4-chloro-3,5-dinitrobenzoate. | phospholipase a2 (pla2) from naja naja atra snake venom was modified with 4-chloro-3,5-dinitrobenzoate, and one major carboxydinitrophenylated (cdnp) pla2 was separated by high performance liquid chromato-graphy. cdnp-pla2 contained only one cdnp group on lys-6 and showed a 93% drop in enzymatic activity. however, carboxydinitrophenylation did not significantly affect the secondary structure of the enzyme molecule as revealed by the cd spectra, and ca2+ binding and antigenicity of cdnp-pla2 were ... | 1994 | 7804147 |
| relationship between the binding sites for an alpha-conotoxin and snake venom neurotoxins in the nicotinic acetylcholine receptor from torpedo californica. | photoinduced cross-links between the iodinated lys26-p-azidobenzoyl derivative of neurotoxin ii from naja naja oxiana cobra venom and nicotinic acetylcholine receptor from torpedo californica (achr) have been studied in the presence of alpha-conotoxin gi from the marine snail c. geographus. preincubation of the achr-enriched membranes with increasing concentrations of alpha-conotoxin gi protects first the gamma subunit from photolabelling and then the delta subunit, the ic50 values being 0.76 an ... | 1994 | 7801351 |
| the use of fluoresceinphosphatidylethanolamine (fpe) as a real-time probe for peptide-membrane interactions. | the characterization of fluoresceinphosphatidylethanolamine (fpe) as a real-time indicator of the electrostatic nature of a membrane surface is described. the conditions appropriate for the labelling of membranes and the implementation of fpe as a tool to monitor the interactions of various peptides with model membranes are outlined. it is shown that of the membrane-active peptides studied, naja naja kaouthia cardiotoxin and pyrularia thionin bind to certain model membranes without insertion. wh ... | 1995 | 7795709 |
| binding mode of phospholipase a2 with a new type of phospholipid analog having an oxazolidinone ring. | inhibition of phospholipases a2 (pla2s) by a new type of monodispersed phospholipid analog, 3-dodecanoyl-4-phosphatidylcholinohydroxymethyl-2-oxazolidinone (oxazolidinone-pc), was investigated by the ph stat assay method using monodispersed 1,2-dihexanoyl-sn-glycero-3-phosphorylcholine (dic6pc) as the substrate. the pla2s used were those from bovine pancreas and cobra (naja naja atra) venom (group i) and from japanese mamushi (agkistrodon halys blomhoffii) venom (group ii). this new-type substra ... | 1995 | 7775386 |
| phospholipase a2 domain formation in hydrolyzed asymmetric phospholipid monolayers at the air/water interface. | phospholipase a2 (pla2) catalyzed hydrolysis of asymmetric 1-caproyl-2-palmitoyl-phosphatidylcholine (6,16-pc) and 1-palmitoyl-2-caproyl-phosphatidylcholine (16,6-pc) lipid monolayers at the air/water interface was investigated. surface pressure isotherms, surface potential and fluorescence microscopy at the air/water interface were used to characterize the asymmetric monolayer systems. cobra (n. naja naja) and bee venom pla2 exhibit hydrolytic activity towards 16,6-pc monolayers at all surface ... | 1995 | 7756350 |
| chemical modification and inactivation of phospholipases a2 by a manoalide analogue. | chemical modification and inactivation of bovine pancreatic, porcine pancreatic, naja naja atra and pseudechis australis phospholipases a2 (pla2s), belonging to group i, and of trimeresurus flavoviridis, vipera russelli russelli and agkistrodon halys blomhoffii pla2s, belonging to group ii, were investigated by the use of a manoalide (mld)-analogue, 1-(2,5-dihydro-hydroxy-5-oxo-3-furanyl)-8,12-dimethyl-4-formyl-3,7, 11-tridecatrienol. at appropriate time intervals, residual pla2 activities towar ... | 1995 | 7755577 |
| [fragments 183-198 and 125-145 of the alpha-subunits of the torpedo californica nicotinic acetylcholinergic receptor binds alpha-bungarotoxin and neurotoxin ii from naja naja oxiana]. | interaction of the mono[125i]iodinated alpha-bungarotoxin and neurotoxin ii naja naja oxiana with the synthetic peptides corresponding to the fragments of the alpha-subunit of nicotinic acetylcholine receptor from torpedo californica was studied. it was found that both toxins bind to the fragments alpha 186-198, alpha 183-198 and alpha 125-145 adsorbed to the 96-well p.e.t.g. assay plates (costar). acm-groups on cys residues did not prevent toxin binding by the peptides studied. determination of ... | 1995 | 7748208 |
| a new class of photoactivatable and cleavable derivatives of neurotoxin ii from naja naja oxiana. synthesis, characterisation, and application for affinity labelling of the nicotinic acetylcholine receptor from torpedo californica. | a new series of photoactivatable and cleavable derivatives of neurotoxin ii from the cobra naja naja oxiana is investigated which can be used for mapping the surface topology of the nicotinic acetylcholine receptor from torpedo electric tissue. the preparation and characterisation of five toxin derivatives, each with a radioactive 125i-azidosalicylamidoethyl-1,3'-dithiopropyl group in a defined position within the primary structure, are described. the photoinduced cross-linking reaction of the t ... | 1995 | 7737199 |
| expression of glutathione s-transferase-cardiotoxin fusion protein in escherichia coli. | we report here the construction of cardiotoxin v gene, from cobra snake venom (naja naja atra), by chemically synthesized oligonucleotides and its expression as a glutathione s-transferase-cardiotoxin fusion protein in the inclusion bodies of escherichia coli. the expression of cardiotoxin fusion protein in protein with a yield of about 35 mg/liter culture was confirmed by highly specific anti-peptide antibodies generated against the unique amino acid residues located at the tip of loop ii of ca ... | 1994 | 7725337 |
| effects of inorganic phosphorus compounds on the hydrolysis of phosphatidylcholine liposomes by phospholipid-deacylating enzymes. | structural requirements of inorganic phosphorus compounds as specific activators or inhibitors for phospholipase a2 and phospholipase b were investigated using orthophosphate, pyrophosphate and polyphosphate. it was observed that orthophosphate and pyrophosphate stimulated the activities of phospholipase a2 from bee venom, snake (naja naja) venom and pig pancreas, and also phospholipase b from the yeast torulaspora delbrueckii. however, polyphosphate was found to act as an inhibitor for phosphol ... | 1995 | 7710702 |
| primary structure of hemoglobin from cobra naja naja naja. | cobra snake naja naja naja hemoglobin shows four bands on triton electrophoresis. we present the primary structure of one alpha and one beta chain. the separation of polypeptide chains was achieved by ion exchange chromatography on carboxymethyl cellulose column. the amino acid sequence was established by automatic edman degradation of the native chains and tryptic and hydrolytic peptides in a gas-phase sequencer. the structural data are compared with those of human and other reptile hemoglobins ... | 1994 | 7710658 |
| monoclonal antibody epitope mapping of plasmodium falciparum rhoptry proteins. | plasmodium falciparum rhoptry proteins of the 140/130/110-kda high molecular weight complex (hmwc) are secreted into the erythrocyte membrane during merozoite invasion. epitopes of membrane-associated hmwc proteins can be detected using rhoptry-specific antibodies by immunofluorescence assays. phospholipase treatment of ring-infected intact human erythrocytes, membrane ghosts, and inside-out vesicles results in the release of the hmwc as demonstrated by immunoblotting. we characterized the membr ... | 1993 | 7682186 |
| beta-bungarotoxin blocks phorbol ester-stimulated phosphorylation of marcks, gap-43 and synapsin i in rat brain synaptosomes. | the phospholipase a2 neurotoxin, beta-bungarotoxin, presynaptically blocks acetylcholine release. its mechanism of action is unknown; however, our previous studies suggest that it inhibits phosphorylation of synaptosomal proteins, which might be expected to decrease neurotransmitter release. in our present study, we found that 1 nm beta-butx blocked phorbol ester-stimulated phosphorylation of gap-43, marcks and synapsin i without affecting their basal phosphorylation. in contrast, a 1 nm concent ... | 1995 | 7676466 |
| synthesis of nitrodiazirinyl derivatives of neurotoxin ii from naja naja oxiana and their interaction with the torpedo californica nicotinic acetylcholine receptor. | five singly modified nitrodiazirine derivatives of neurotoxin ii (nt-ii) from naja naja oxiana were obtained after nt-ii reaction with n-hydroxysuccinimide ester of (2-nitro-4-[3-(trifluoromethyl)-3h-diazirin-3yl]phenoxy)acet ic acid followed by chromatographic separation of the products. to localize the label positions, each derivative was first uv-irradiated and then subjected to reduction, carboxymethylation, and trypsinolysis. tryptic digests were separated by reversed phase-hplc, the labele ... | 1995 | 7662107 |
| highly efficient immobilization of phospholipase a2 and its biomedical applications. | a new method for the immobilization of phospholipase a2 (pla2) has been developed to enhance the activity retention of immobilized pla2. when pla2 from the venom of agkistrodon piscivorus piscivorus was pretreated with 4-nitro-3-octanoyl-oxybenzoic acid to acylate epsilon-amino groups of two lysines (lys-7 and lys-10) and the resulting acylated enzyme was covalently coupled onto carbonyldiimidazole-activated cross-linked agarose beads, the immobilized acylated enzyme showed high retention of act ... | 1995 | 7658163 |
| phospholipase a2 as a mechanosensor. | osmotic swelling of large unilamellar vesicles (luvs) causes membrane stretching and thus reduces the lateral packing of lipids. this is demonstrated to modulate strongly the catalytic activity of phospholipase a2 (pla2) toward a fluorescent phospholipid, 1-palmitoyl-2-[(6-pyren-1-yl)]decanoyl-sn-glycero-3-phosphocholine (ppdpc) residing in luvs composed of different unsaturated and saturated phosphatidylcholines. the magnitude of the osmotic pressure gradient delta omega required for maximal pl ... | 1995 | 7612831 |
| primary structure of a cytotoxin-like basic protein from naja naja naja (indian cobra) venom. | the complete amino acid sequence of a cytotoxin-like basic protein (clbp) from the venom of naja naja naja (indian cobra) was determined by manual degradation using a 4-dimethylaminoazobenzene-4'-isothiocyanate double-coupling method. peptide fragments obtained by chemical cleavage with cyanogen bromide and enzymic cleavages with trypsin and staphylococcus aureus proteases for sequence analysis were purified by reversed-phase chromatography. the total number of amino acid residues was 61, with l ... | 1995 | 7558599 |