Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
|---|
| critical role of a hydrogen bond in the interaction of phospholipase a2 with transition-state and substrate analogues. | the inhibition of phospholipase a2 by an amide substrate analogue, 1-hexadecylthio-2-hexadecanoyl-amino-1,2-dideoxy-sn-glycero-3-phos phocholine, and a phosphonate transition-state analogue, 1-hexadecylthio-1-deoxy-2-hexadecylphosphono-sn-glycero-3-ph osphocholine, is dramatically influenced by ph. however, these two inhibitors show opposite ph dependencies. the amide analogue acts more potently under basic conditions, whereas the phosphonate acts more potently under acidic conditions. in both c ... | 1991 | 1924395 |
| synthesis and characterization of a heterobifunctional mercurial cross-linking agent: incorporation into cobratoxin and interaction with the nicotinic acetylcholine receptor. | the heterobifunctional organomercurial reagents 3-(acetoxymercurio)- and 3-(chloromercurio)-5-nitrosalicylaldehyde were prepared, characterized in model studies, and used to probe the interaction between cobratoxin, purified from the venom of the thailand cobra (naja naja siamensis), and the affinity-purified nicotinic acetylcholine receptor (acchr) from torpedo california electroplax. these reagents may also be useful in introducing chemically well-defined heavy metal atoms into proteins contai ... | 1991 | 1854732 |
| anionic subsites of the catalytic center of acetylcholinesterase from torpedo and from cobra venom. | a peptide of acetylcholinesterase (acchoease; acetylcholine acetylhydrolase, ec 3.1.1.7) from the venom of the cobra naja naja oxiana labeled by the affinity reagent n,n-dimethyl-2-phenylaziridinium (dpa) has been identified. the sequence is gly-ala-glu-met-trp-asn-pro-asn. in acchoease from torpedo californica, a homologous peptide was labeled and isolated. its sequence is ser-gly-ser-glu-met-trp-asn-pro-asn, representing positions 79 through 87. in both cases labeling can be prevented by 0.1 m ... | 1991 | 2068091 |
| extensive multiplicity of the miscellaneous type of neurotoxins from the venom of the cobra naja naja naja and structural characterization of major components. | a multiplicity of miscellaneous type neurotoxins were detected in the venom of the cobra naja naja naja by use of reverse-phase hplc and fplc. the primary structures of major forms were determined, giving 4 novel structures. all four contain 62-65 residues, with 10 half-cystine residues and resemble the miscellaneous type of toxins from other naja species. differences within the species are extensive, exchanges occur at 27 positions, giving only 58% residue identity between all forms. however, t ... | 1991 | 2060629 |
| [spatial structure of the basic chain of the neurotoxin i molecule from the venom of cobra naja naja oxiana and its crystal packing]. | the structure of the alpha-carbon chain was solved by molecular replacement method at 2.7 a resolution. neurotoxin i (ntx-i) is one of the main protein components purified from the venom of the central asian cobra naja naja oxiana. ntx-i is known to bind specifically to acetylcholine receptors thus preventing the transmission of the neuroconductivity signal from synapses to muscles. ntx-i crystals were grown either by vapour diffusion or dialysis methods using specially prepared microdialysis ce ... | 1991 | 2064629 |
| cobra venom phospholipase a2: naja naja naja. | 1991 | 2051932 | |
| purification and characterization of a neurotoxic phospholipase a2 from indian cobra (naja naja naja) venom. | snake venoms contain multimolecular forms of phospholipase a2 which are diverse with respect to their pharmacological properties. a neurotoxic pla2 from naja naja naja venom has been purified in two steps. (1) the whole venom was fractionated on cm-sephadex c-25 column; 4.6% of the total pla2 activity recovered was found in the nn-v fraction. (2) the nn-vb-pla2 fraction was purified to homogeneity by gel filtration of fraction nn-v on sephadex g-50. it is a basic protein with a mol. wt between 1 ... | 1991 | 1814010 |
| ultrastructure of the tongue and anterior process of the sublingual plica in four species of venomous snakes. | the general histology and ultrastructure of the tongue and anterior process of the sublingual plica of four taiwanese venomous snakes, the chinese cobra (naja naja atra), banded krait (bungarus multicinctus), taiwan habu (trimeresurus mucrosquamatus), and bamboo snake (trimeresurus stejnegeri stejnegeri) are described. the tongue fork exhibits a mid-dorsal invagination that broadens gradually toward its base. no mid-ventral invagination is observed. the epithelial cells on both dorsal and ventra ... | 1991 | 29865528 |
| intracellular mechanisms involved in short-term regulation of net protein synthesis in pancreatic acini. | the mechanisms regulating the net synthesis of digestive enzymes during short-term stimulation by agonists were examined in pancreatic acini isolated from the rat. dispersed pancreatic acini were stimulated for up to 60 min with various concentrations of cholecystokinin octapeptide (cck-op), carbachol, a23187, 4 beta-phorbol 12-myristate 13-acetate (pma). the effects of these agonists on net protein synthesis was determined by measuring the incorporation of [3h]leucine or [35s]methionine into pr ... | 1991 | 1708286 |
| extracellular phospholipase a2 and histamine release from rat peritoneal mast cells. | phospholipase a2 (pla2) from cobra (naja naja) venom and pla2 from porcine pancreas accelerated ige antibody-mediated histamine release from rat peritoneal mast cells. these enhancements were clearly abrogated by heating the enzymes and pretreatment with parabromophenacyl bromide, mepacrine and antiflammin. indomethacin (cyclooxygenase inhibitor) and aa-861 (lipoxygenase inhibitor) did not affect the enhancement by pla2. these results indicate that extracellular pla2 enhances the ige antibody-me ... | 1991 | 1725674 |
| comparative effects of phospholipase a2 neurotoxins and enzymes on membrane potential and na+/k+ atpase activity in rat brain synaptosomes. | beta-bungarotoxin (beta-butx) and notexin are phospholipase a2 (pla2) neurotoxins which cause an irreversible blockade of neurotransmitter release through specific and potent effects at the presynaptic nerve terminal; however, their mechanism of action is uncertain. we examined the effects of beta-butx and notexin on na+/k+ atpase activity using sprague-dawley rat brain synaptosomes in order to determine if alterations in activity might modulate neurotoxin-induced depolarization. treatment of sy ... | 1991 | 1648801 |
| comparison of group i and ii soluble phospholipases a2 activities on phagocytic functions of human polymorphonuclear and mononuclear phagocytes. | soluble phospholipase a2 (pla2) purified from rheumatoid synovial fluid (group ii) and repurified naja naja venom pla2 (group i) were compared for their influence on phagocytic activity of human polymorphonuclear (pmn) and mononuclear (mo) phagocytes. group ii pla2 reduced chemotaxis, adhesiveness, and intracellular bactericidal activity (icba) and induced release of muramidase from pmns. group i pla2 suppressed chemotaxis, and enhanced icba but had no influence on other phagocytic functions. gr ... | 1991 | 1649131 |
| comparative enzymatic composition of brazilian coral snake (micrurus) venoms. | 1. venoms of 11 coral snake taxa, including micrurus albicinctus, m. corallinus, m. frontalis altirostris, m. f. brasiliensis, m. f. frontalis, m. fulvius fulvius, m. ibiboboca, m. lemniscatus ssp., m. randonianus, m. spixii spixii, and m. surinamensis surinamensis, were examined for 13 enzymatic activities. 2. these were compared with venoms of three outgroup taxa: naja naja kaouthia, bungarus multicinctus, and bothrops moojeni. 3. enzyme activity levels in micrurus venoms were highly variable ... | 1991 | 1662592 |
| effects of a cardiotoxin from naja naja kaouthia venom on skeletal muscle: involvement of calcium-induced calcium release, sodium ion currents and phospholipases a2 and c. | snake venom cardiotoxin (ctx) fractions induce contractures of skeletal muscle and hemolysis of red blood cells. the fractions also contain trace amounts of venom-derived phospholipase a2 (pla2) contamination and activate tissue phospholipase c (plc) activity. the present study examines the mechanisms of action of a ctx fraction from naja naja kaouthia venom in skeletal muscle. sphingosine competitively antagonized ctx-induced red blood cell hemolysis, but not skeletal muscle contractures. ctx r ... | 1991 | 1666202 |
| effects of anti-inflammatory drugs on rat hind-paw swelling caused by phospholipase a2 from naja naja atra venom. | rat hind-paw swelling was induced dose-dependently by subplantar injection of acidic phospholipase a2 (nnavpla2) from naja naja atra venom. diphenhydramine and methysergide pretreatment greatly reduced the swelling effect caused by nnavpla2. several doses of compound 48/80 given to deplete the histamine content of rat hind paw, also greatly suppressed nnavpla2-induced paw swelling. the paw swelling caused by nnavpla2 was reduced following pretreatment with bw 755c, a dual inhibitor of cyclooxyge ... | 1991 | 1683689 |
| absence of lung reactions after complement depletion during dialysis: an experimental study in pigs. | sequestration of 111in-labeled neutrophils (polymorphonuclear leukocytes--pmns) in the lungs during sham dialysis was studied dynamically using a gamma camera. five animals were pretreated with cobra venom factor, naja naja (cvf), to achieve depletion of the complement system, mainly c5a. seven animals were studied without pretreatment with cvf. central hemodynamics and gas exchange were studied as well as neutrophil function using luminescence and aggregation. in the control group there was a s ... | 1991 | 1741685 |
| isolation and fundamental characteristics of a phospholipase b inhibitor from autolyzed torulaspora delbrueckii. | phospholipase b inhibitor was found in the autolyzate of yeast cells, torulaspora delbrueckii. the inhibitor was purified to homogeneity by ethanol precipitation, gel filtration with sephadex g-10, ion-exchange chromatography with deae-sephacel, and gel filtration with asahipak gs-320. on thin-layer chromatography the purified inhibitor was detected with the hanes-isherwood reagent, which is used to detect phosphorus. the activity of the inhibitor was not affected by heat treatment at 100 degree ... | 1991 | 1760134 |
| interleukin-1 alpha stimulates the release of prostaglandin e2 and phospholipase a2 from fetal rat calvarial cells in vitro: relationship to bone nodule formation. | we have shown previously that interleukin-1 (il-1) has biphasic effects on the formation of bone nodules in long-term cultures of fetal rat calvarial (rc) cells (ellies and aubin, cytokine 2:430-437, 1990). to determine the role of arachidonic acid metabolism in this process, we have examined the release of prostaglandin e2 (pge2) and phospholipase a2 (pla2) from rc cells under conditions that allowed concomitant analysis of the formation of bone nodules. recombinant human il-1 alpha (rhil-1 alp ... | 1991 | 1785374 |
| the involvement of polymorphonuclear leukocytes in the pathogenesis of bronchopneumonia in calves. ii. granulocyte-induced changes in erythrocyte membrane phospholipid topology. | phospholipid topology in erythrocyte membranes of bronchopneumonic calves and changes in phospholipid asymmetry induced by incubation of erythrocytes with neutrophils of diseased calves were examined. using aminophospholipid tracing by non-penetrating probe, trinitrobenzenesulfonic acid, and phospholipid hydrolysis by specific phospholipase a2 from naja naja venom and sphingomyelinase from staphylococcus aureus it was stated that in erythrocytes from diseased calves phosphatidylserine and, to so ... | 1991 | 1785438 |
| interfacial catalysis by phospholipase a2: substrate specificity in vesicles. | the binding equilibrium of phospholipase a2 (pla2) to the substrate interface influences many aspects of the overall kinetics of interfacial catalysis by this enzyme. for example, the interpretation of kinetic data on substrate specificity was difficult when there was a significant kinetic contribution from the interfacial binding step to the steady-state catalytic turnover. this problem was commonly encountered with vesicles of zwitterionic phospholipids, where the binding of pla2 to the interf ... | 1991 | 1854740 |
| [1-14c]oleate-labeled autoclaved yeast: a membranous substrate for measuring phospholipase a2 activity in vitro. | radiolabeled, autoclaved yeast were tested as a substrate for mammalian phospholipase a2 activity because the only other membranous substrate used for this purpose, autoclaved escherichia coli, totally lacks a major mammalian phospholipid, phosphatidylcholine. candida albicans were grown in the presence of [1-14c]oleate and then autoclaved. sixty three percent of the incorporated label was in yeast phospholipid, and more than 95% of that was in the 2-acyl position. the distribution of label in t ... | 1991 | 1872466 |
| comparison of the catalytic properties of phospholipase a2 from pancreas and venom using a continuous fluorescence displacement assay. | phospholipases a2 from pig pancreas and the venoms from bee, naja naja and crotalus atrox have been studied by using a new continuous fluorescence displacement assay that utilizes normal phospholipid substrates [wilton (1990) biochem. j. 266, 435-439]. with limiting amounts of substrate, the assay demonstrated stoichiometric conversion into products with both pancreatic and venom enzymes, and thus would allow phospholipid determination at concentrations down to about 0.1 microm. the substrate sp ... | 1991 | 1898370 |
| acute lung injury induced by phospholipase a2. structural and functional changes. | on the basis of the observation that serum levels of phospholipase a2 (pla2) are elevated in pancreatitis and systemic sepsis, and the association of these conditions with the subsequent development of acute lung injury, the present investigation examined the structural and physiologic consequences of intratracheal administration of pla2 to adult male rats. rats received direct intratracheal instillation of either control vehicle or 40,000 units/kg of pla2 repurified from naja naja venom. animal ... | 1991 | 1902636 |
| kinetic characterization of phospholipase a2 modified by manoalogue. | manoalogue, a synthetic analogue of the sea sponge-derived manoalide, has been previously shown to partially inactivate the phospholipase a2 from cobra venom (reynolds, l. j., morgan, b. p., hite, e. d., mihelich, e. d., & dennis, e. a. (1988) j. am. chem. soc. 110, 5172) by reacting with enzyme lysine residues. in the present study, the inactivation of the phospholipases a2 from pig pancreas, bee venom, and cobra (naja naja naja) venom by manoalogue was studied in detail. manoalogue-treated enz ... | 1991 | 1911741 |
| fusion of sphingomyelin vesicles induced by proteins from taiwan cobra (naja naja atra) venom. interactions of zwitterionic phospholipids with cardiotoxin analogues. | egg sphingomyelin vesicles were used to assay aggregation/fusion activities of proteins from taiwan (naja naja atra) venom to avoid the problem of phospholipase a2 contamination during protein purification. it led to the identification of a new cardiotoxin (ctx) analogue protein (ctx v) with major aggregation/fusion, but few hemolysis, activities. on the contrary, cardiotoxin (ctx iii) induced significant hemolysis of human red blood cells but exhibited few aggregation/fusion activities. to stud ... | 1991 | 1993698 |
| development of an elisa to assess the potency of horse therapeutic antivenom against thai cobra venom. | an elisa for the quantitation of antibodies against naja naja siamensis venom proteins has been developed for use as a possible replacement for the in vivo neutralization assay of antivenom potency. comparison was made with three preparations of venom proteins as antigens of elisa: these were the crude venom, a toxin fraction and the purified principle postsynaptic neurotoxin of the thai cobra. eight batches of horse monovalent therapeutic anti-cobra antivenom, one of which served as positive re ... | 1991 | 1995711 |
| structure-function relationships among neurotoxic phospholipases: nn-xiii-pla2 from indian cobra (naja naja naja) and vrv pl-v from russell's viper (vipera russelli) venoms. | though venom phospholipases induce various pharmacological effects their mechanism of action is in some cases unclear. there may be separate pharmacological sites on the venom phospholipase molecule. in order to understand the structure-function relationships among venom phospholipases, studies on interaction of venom phospholipases with its antibodies and various alkaloids were carried out. the alkaloids aristolochic acid, ajmaline and reserpine were incapable of inhibiting the phospholipase a2 ... | 1991 | 2028476 |
| snake venom cardiotoxins and bee venom melittin activate phospholipase c activity in primary cultures of skeletal muscle. | the effects of cardiotoxin fractions from naja naja kaouthia and naja naja atra snake venoms and synthetic melittin peptide were examined on lipolytic activity in red blood cells and primary skeletal muscle cultures. both native cardiotoxin fractions caused considerable production of free fatty acids in red blood cells. this production was abolished when the fractions were first treated with p-bromophenacyl bromide to reduce the venom phospholipase a2 activity contamination. in equine and human ... | 1991 | 2054159 |
| lipopolysaccharide-induced pulmonary vascular sequestration of polymorphonuclear leukocytes is complement independent. | lipopolysaccharide (lps) injected intravenously produces leukopenia and sequestration of polymorphonuclear leukocytes (pmn) in the pulmonary vascular bed. to evaluate the role of complement in this process, we used c5-sufficient (b10.d2/nsn) and c5-deficient (b10.d2/osn) mice and sprague-dawley rats depleted of complement with naja naja cobra venom factor (cvf). we found a comparable increase in the number of pmn in lung tissue of c5-sufficient and c5-deficient mice given escherichia coli lps (0 ... | 1991 | 2064126 |
| procoagulant activities in venoms from central asian snakes. | the venoms from central asian snakes (echis carinatus, echis multisquamatus, vipera ursini, vipera lebetina, agkistrodon halys halys and naja naja oxiana) contain several enzymes with amidolytic- and procoagulant activity. we have characterized the activities and the mol. wts of the venom enzymes that are able to convert a number of commercially available chromogenic substrates for activated coagulation factors. the chromogenic substrate cleavage patterns obtained for the crude venoms may be hel ... | 1991 | 1830705 |
| effects of chemical modification on enzymatic and toxicological properties of phospholipases a2 from naja naja naja and vipera russelli snake venoms. | the effects of chemical modification with 4-nn-dimethyl amino azo benzene-4'-isothiocyanate on various biological activities of phospholipases a2, nn-xiii-pla2 from naja naja naja and vrv-pl-viiia from vipera russelli snake venoms were investigated. modification of the enzymes resulted in significant reduction of lethal, hemolytic, anticoagulant and enzymatic activities. the km value of the modified enzymes was increased. the modified enzymes failed to induce edema in the foot pads of mice and w ... | 1991 | 1801318 |
| comparative chromatography of brazilian coral snake (micrurus) venoms. | 1. elution profiles of 11 coral snake venoms, including those of micrurus albicinctus, m. corallinus, m. frontalis altirostris, m. f. brasiliensis, m. f. frontalis, m. fulvius fulvius, m. ibiboboca, m. lemniscatus ssp., m. rondonianus, m. spixii spixii and m. surinamensis surinamensis, were compared using high performance gel filtration and reverse phase media. 2. micrurus venom profiles were compared with those of "outgroup" taxa bothrops moojeni, naja naja kaouthia and bungarus multicinctus. 3 ... | 1991 | 1756614 |
| suicide-inhibitory bifunctionally linked substrates (siblinks) as phospholipase a2 inhibitors. mechanistic implications. | novel phospholipids that function as mechanism-based inhibitors for phospholipase a2 (pla2) are described. pla2-catalyzed hydrolysis of the sn-2 ester of these suicide-inhibitory bifunctionally linked substrates (siblinks) followed by a cyclization reaction generates a cyclic anhydride at the active site of the enzyme which leads to inhibition. structure/activity relationships for the siblinks substituents in the sn-1 and sn-2 position are delineated. time courses and efficiency of siblinks inhi ... | 1991 | 2002046 |
| calcium ion independent membrane leakage induced by phospholipase-like myotoxins. | the two snake venom myotoxins ammodytin l and myotoxin ii, purified respectively from vipera ammodytes ammodytes and bothrops asper, have phospholipase-like structures but lack an asp-49 in the active site and are without normal phospholipase activity. the interaction of these proteins with different types of liposomes indicated that the myotoxins were able to provoke rapid and extensive release of the aqueous content of liposomes. leakage was measured by two different methods: fluorescence dequ ... | 1992 | 1334427 |
| immunochemical properties of naja naja atra (taiwan cobra) phospholipase a2 using polyclonal and monoclonal antibodies. | the immuno-chemical properties of naja naja atra phospholipase a2 (nna-pla2) were studied by using the chemically modified pla2 derivatives and the pla2 homologues toward anti-nna-pla2 polyclonal and monoclonal antibodies. anti-nna-pla2 polyclonal antibodies inhibited the enzymatic activity of nna-pla2 and hemachatus haemachatus de-i by 87% and 68%, respectively. however, the enzymatic activities of naja nigricollis cms-9 and notexin were not significantly affected by the polyclonal antibodies. ... | 1992 | 1373010 |
| renaturation of cobra venom phospholipase a2 expressed from a synthetic gene in escherichia coli. | cobra venom (naja naja naja) phospholipase a2 (pla2) contains 14 cysteines in the form of 7 disulfide bonds amongst its 119 amino acids. a gene encoding the pla2 was synthesized and inserted into a bacterial expression vector containing the phage lambda pl promoter. in order to obtain protein without the initiating methionine at the n-terminus, a factor xa site was engineered upstream from the pla2 gene. upon heat-induction of the cells transformed with the expression plasmid, the protein is pro ... | 1992 | 1730025 |
| toxicities, ld50 prediction and in vivo neutralisation of some elapid and viperid venoms. | toxicity levels of elapid (naja naja and naja oxiana) viperid (vipera lebetina and vipera russelli) venoms for mice and rat for intraperitoneal intravenous and intramuscular routes have been determined. the data have been analysed using a mathematical expression to calculate lethal venom concentrations in human snake bite cases. further, in vivo neutralisation of snake venom potency (after experimental injection) using high voltage-low current electric shock treatment has been attempted. this tr ... | 1992 | 1294479 |
| [pharmacokinetics of cytotoxin 14 from naja naja atra venom]. | the pharmacokinetics of cytotoxin 14 (ct 14) from naja naja atra venom was studied with biotin-avidin enzyme-linked immunosorbent assay. the plasma concentration-time curve of ct 14 after bolus i.v. 0.2 mg.kg-1 into rabbits was found to fit a two-compartment open model. t1/2 alpha was 5.8 +/- 0.6 min and t1/2 beta was 3.5 +/- 0.2 h. a rapid absorption was seen after im injection (0.5 mg.kg-1) to rabbits. the peak level was 260 +/- 90 ng.ml-1 and tpeak was 13.6 +/- 2.4 min. the absolute bioavaila ... | 1992 | 1302445 |
| antiflammins. anti-inflammatory activity and effect on human phospholipase a2. | two anti-inflammatory peptides (antiflammins) corresponding to a high amino acid similarity region between lipocortin i and uteroglobin were tested for their ability to inhibit purified human synovial fluid phospholipase a2 (hsf-pla2). no inhibitory activity was observed, even at such high concentrations of peptides as 50 microm. when antiflammins were preincubated with the enzyme and/or the substrate, no hsf-pla2 inhibition was detected. in vivo anti-inflammatory activity of these peptides was ... | 1992 | 1387313 |
| [specific killing of human leukemic t-cells by a monoclonal antibody coupled to the cytotoxin from chinese cobra]. | the immunotoxin (it) was prepared by conjugating cytotoxin from chinese cobra (naja naja atra) venom with monoclonal antibody (mcab) wu71 directed to human t-cells. first, calcium ions were used to suppress the cytolytic reaction while cell antigen was allowed to react with mcab. then magnesium ions and the chelating agent egta were used to abolish the calcium inhibition. with this treatment, the it showed high cytotoxicity for the leukemic cell line cem, which was antigen positive (82.4% of the ... | 1992 | 1394735 |
| lipopolysaccharide-induced stimulation of alveolar macrophage opsonin-independent phagocytosis. | alveolar macrophage (am) opsonin-independent phagocytosis may be an important process by which bacteria are cleared from the airspaces. although it has been shown that clearance of bacteria from the lung is altered in association with endotoxemia, the effect of endotoxemia on opsonin-independent phagocytosis is unknown. because alterations in am opsonin-independent phagocytosis could potentially influence bacterial clearance in the lung, we studied the effects of the intravenous injection of esc ... | 1992 | 1405605 |
| effects of snake venom phospholipase a2 toxins (beta-bungarotoxin, notexin) and enzymes (naja naja atra, naja nigricollis) on aminophospholipid asymmetry in rat cerebrocortical synaptosomes. | the effects of snake venom phospholipase a2 (pla2) toxins (beta-bungarotoxin, notexin) and pla2 enzymes (naja nigricollis, naja naja atra) on aminophospholipid asymmetry in rat cerebrocortical synaptic plasma membranes (spm) were examined. incubation of intact synaptosomes with 2 mm 2,4,6-trinitrobenzene sulfonic acid (tnbs) for 40 min, under non-penetrating conditions, followed by spm isolation, allowed us to calculate the percentage of phosphatidylethanolamine (pe) and phosphatidylserine (ps) ... | 1992 | 1417932 |
| inhibition of phosphorylation of synapsin i and other synaptosomal proteins by beta-bungarotoxin, a phospholipase a2 neurotoxin. | some snake venom neurotoxins, such as beta-bungarotoxin (beta-butx), which possess relatively low phospholipase a2 (pla2) activity, act presynaptically to alter acetylcholine (ach) release both in the periphery and in the cns. in investigating the mechanism of this action, we found that beta-butx (5 and 15 nm) inhibited phosphorylation, in both resting and depolarized synaptosomes, of a wide range of proteins, including synapsin i. naja naja atra pla2, which has higher pla2 activity, also inhibi ... | 1992 | 1431893 |
| activation of bovine factor v by an activator purified from the venom of naja naja oxiana. | the crude venom of many elapid snakes appeared to contain proteins that activated blood coagulation factor v. the factor v activator present in the venom of naja naja oxiana was purified to homogeneity by chromatography on a mono-s column. the activator was a single chain protein with an apparent mol. wt of 48,000, as judged by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate and by gel permeation chromatography on sephacryl s200. activation of bovine factor v by the ... | 1992 | 1440644 |
| sphingolipid metabolism and signal transduction: inhibition of in vitro phospholipase activity by sphingosine. | sphingosine inhibits protein kinase c activity in vitro and has been used to implicate this enzyme in signal transduction and cell function. we report that sphingosine directly inhibits phospholipases a2 and d. sphingosine inhibits ca(2+)-dependent phospholipases a2 from naja naja, porcine pancreas, crotalus adamanteus, human disc and neutrophil in a dose-dependent manner with ic50 values ranging from 5-40 microm using [1-14c]oleate-labelled autoclaved e. coli (20 microm) as substrate. inhibitio ... | 1992 | 1504102 |
| binding properties of pyrularia thionin and naja naja kaouthia cardiotoxin to human and animal erythrocytes and to murine p388 cells. | pyrularia thionin and snake venom cardiotoxin are strongly basic peptides which induce hemolysis, depolarization of muscle cells and activation of endogenous phospholipase a2. an earlier study of the hemolysis reaction indicated that the two peptides bind to and compete for the same site on human erythrocytes. a recent study examined the hemolysis induced by both peptides as the phosphate and ca2+ content of the reaction mixture was varied. the results of the recent study (vernon, l. p. and roge ... | 1992 | 1509490 |
| mojave toxin affects fusion of myoblasts and viability of myotubes in cell cultures. | mojave toxin is a neurotoxic, heterodimeric phospholipase isolated from the venom of crotalus scutulatus scutulatus. responses of primary rat muscle cell cultures and clonal muscle cell lines to treatment with mojave toxin and its constituent subunits were examined. continuous exposure of cells to 0.5 microm or 1.0 microm mojave toxin or the basic subunit, added 24 hr after plating, prevented fusion of primary myoblasts and c2 myoblasts to multinucleate myotubes. under the same experimental cond ... | 1992 | 1509491 |
| a novel type of phospholipase a2 inhibitor, thielocin a1 beta, and mechanism of action. | thielocin a1 beta, a novel phospholipase a2 inhibitor, was isolated from thielavia terricola rf-143. it inhibited various phospholipase a2s in a dose-dependent manner. among these, group ii phospholipase a2 from rat was most sensitive to thielocin a1 beta (ic50 = 0.0033 microm). the inhibition of phospholipase a2 by thielocin a1 beta was independent of ca2+ and substrate concentration. in addition, the inhibition of rat group ii phospholipase a2 was noncompetitive (ki = 0.0068 microm) and revers ... | 1992 | 1517154 |
| cinatrins, a novel family of phospholipase a2 inhibitors. ii. biological activities. | cinatrins a, b and c3 inhibited phospholipase a2 purified from rat platelets in a dose-dependent manner. cinatrin c3, the most potent component (ic50 70 microm), was noncompetitive with a ki value of 36 microm. cinatrins b and c3 also inhibited both porcine pancreas and naja naja venom phospholipase a2. inhibition of rat platelet phospholipase a2 by cinatrin c3 was independent of ca2+ and substrate concentration. comparison with duramycin, another phospholipase a2 inhibitor, displayed inhibition ... | 1992 | 1548189 |
| preparation, characterization and immunogenicity of various polymers and conjugates of elapid postsynaptic neurotoxins. | seven polymeric forms and conjugates of purified principal postsynaptic neurotoxins of naja naja siamensis (nns), ophiophagus hannah (oh) and bangarus fasciatus (bf) have been synthesized by controlled polymerization in which only 29-60% of the toxins were allowed to react. a carbodiimide (ecdi) and glutaraldehyde (ga) were used as coupling agents while bsa and tetanus toxoid (tt) were used as carriers. the antigenic mosaic of these immunogens was: nns-ecdi, nns-bf-oh-ecdi, nns-bsa-ecdi, nns-tt- ... | 1992 | 1565098 |
| differential hydrolysis of 1-alkyl-2-acyl and diacylglycerophosphocholines by human and non-human phospholipases a2. | the activity of two human phospholipases a2, purified from synovial fluid and lumbar disc herniations, was tested using alkylacyl- and diacylglycerophosphocholines and the influence of the chemical link at the sn-1 position of glycerol was investigated. both enzymes exhibited 2.5-3-fold selectivity for 1-ester-linked compared to 1-ether-linked phosphatidylcholine. no significant selectivity was observed with pancreatic phospholipase a2 while naja naja naja venom enzyme was more efficient against ... | 1992 | 1576169 |
| direct effects and augmentation of airway smooth muscle contraction caused by phospholipase a2. | we examined the effect of phospholipase a2 (pla2; naja naja) on isometric tracheal smooth muscle force generation in guinea pig trachealis in situ. direct application of pla2 to the surface of the trachea caused dose-related contraction of tracheal smooth muscle. in seven guinea pigs, a dose/density of 100 micrograms/cm2 pla2 caused active tension (at) that began immediately and was maximum (1.32 +/- 0.13 g/cm) at 5 min (p less than 0.01 versus baseline tension). pla2 also augmented the contract ... | 1992 | 1596019 |
| [biotin-avidin-elisa for cytotoxin purified from cobra venom]. | a technique combining the biotin-avidin amplifying system with sandwich enzyme-linked immunosorbent assay (b-a-elisa) was developed for the microassay of the cytotoxin from naja naja atra venom. the horse-peroxidase was used as the marker and polystyrene microhemagglutination plates as solid carrier. the sensitivity was 0.5 ng.ml-1. the assay range was 1.25-320 ngml-1 with coefficient of variation of 4.9% (intragroup) and 8.1% (intergroups), respectively. | 1992 | 1598840 |
| [pharmacological study on naja naja kaouthia lesson. iii. effects of 50% ethanolic extracts from liver and gall bladder on phagocytic activity of mouse reticuloendothelial system]. | effects of 50% ethanolic extracts from the liver and the gall bladder of naja naja kaouthia lesson (cob-l or cob-g) were studied on the phagocytic activity of a mouse reticuloendothelial system. the clearance-rate of carbon was shortened by the oral administration of cob-l or cob-g (50 or 200 mg/kg). cob-l or cob-g promoted the phagocytosis of latex by peritoneal macrophages (m phi). furthermore, effects of these extracts on the peritoneal m phi were biochemically investigated using in vitro exp ... | 1992 | 1608042 |
| reversibility of the activation of soluble phospholipase a2 on lipid bilayers: implications for the activation mechanism. | the time-courses of hydrolysis of large vesicles of dipalmitoylphosphatidylcholine were compared using four species of phospholipase a2 (agkistrodon piscivorus piscivorus, crotalus adamanteus and naja naja venoms and porcine pancreatic). in all four cases, the hydrolysis rate suddenly increases 10 to 100-fold at the time (tau) when a specific mole fraction of reaction products has accumulated. the intrinsic fluorescence emission of the three venom enzymes also increases suddenly at time tau. bot ... | 1992 | 1643108 |
| comparative characterization of two toxic phospholipases a2 from indian cobra (naja naja naja) venom. | indian cobra venom contains many phospholipase a2 (pla2) toxins. in the present study two toxic pla2s have been purified from the indian cobra (naja naja naja) venom by column chromatography. the nn-xia-and nn-xib-pla2s have mol. wts between 10,700 and 15,000. the nn-xia-pla2 induces myotoxic effects, oedema and neurotoxicity in mice and has an i.p. ld50 of 8.5 mg/kg body weight. the nn-xia-pla2 is also cytotoxic to ehrlich ascites tumour cells. the other pla2, nn-xib, in contrast has an i.p. ld ... | 1992 | 1279838 |
| alpha-cobratoxin: proton nmr assignments and solution structure. | the solution structure of alpha-cobratoxin, a neurotoxin purified from the venom of the snake naja naja siamensis, at ph 3.2 is reported. sequence-specific assignments of the nmr resonances was attained by a combination of a generalized main-chain-directed strategy and of the sequential method. the nmr data show the presence of a triple-stranded beta-sheet (residues 19-25, 36-41, and 52-57), a short helix, and turns. an extensive number of noe cross peaks were identified in the noesy nmr maps. t ... | 1992 | 1317211 |
| effect of calcium and phosphate ions on hemolysis induced by pyrularia thionin and naja naja kaouthia cardiotoxin. | pyrularia thionin is a strongly basic bioactive peptide of 47 amino acids isolated from nuts of pyrularia pubera. it is hemolytic, cytotoxic and activates an endogenous phospholipase a2 in 3t3 cells. earlier studies have shown that the cardiotoxin from naja naja kaouthia has similar activities and binds to the same site as pyrularia thionin. since the peptides appear to bind to the phospholipids of cell membranes to elicit their cellular responses, the effect of modifying the electrostatic envir ... | 1992 | 1509489 |
| purification and properties of the l-amino acid oxidase from monocellate cobra (naja naja kaouthia) venom. | 1. the l-amino acid oxidase of the monocellate cobra (naja naja kaouthia) venom was purified to electrophoretic homogeneity. the molecular weight of the enzyme was 112,200 as determined by sephadex g-200 gel filtration chromatography, and 57,400 as determined by sds-polyacrylamide gel electrophoresis. 2. the enzyme had an isoelectric point of 8.12 and a ph optimum of 8.5. it showed remarkable thermal stability, and, unlike many venom l-amino acid oxidase, was also stable in alkaline medium. the ... | 1992 | 1612186 |
| implications of a consensus recognition site for phosphatidylcholine separate from the active site in cobra venom phospholipases a2. | a model structure of naja naja kaouthia cobra venom phospholipase a2 has been constructed by utilizing molecular modeling techniques. analysis of the model and available biochemical data reveal the presence in this enzyme of a putative recognition site for choline derivatives in loop 57-70 made up of residues trp-61, tyr-63, phe-64, and lys-65, together with glu-55. the magnitude and shape of the electrostatic potential in this binding site are approximately 80% similar to that in the mcpc603 an ... | 1992 | 1550815 |
| structural features of carbohydrate moieties in snake venom glycoproteins. | the structures of the carbohydrate moieties of glycoproteins in snake venoms are largely unknown. in the present study, we have analyzed venoms of several species of snakes as well as plasma and tissue glycoproteins from one species of cobra (naja naja kaouthia) by lectin affinity staining of western blots. the data demonstrate that glycoproteins in cobra venom invariably contain terminal alpha-galactosyl residues with negligible proportions of sialic acids. interestingly, however, terminal alph ... | 1992 | 1731789 |
| use of hplc to demonstrate variation of venom toxin composition in the thailand cobra venoms naja naja kaouthia and naja naja siamensis. | the composition of the venoms of naja naja kaouthia and naja naja siamensis from different commercial sources has been investigated using both ion-exchange and reverse-phase high-pressure liquid chromatography (rp-hplc) in order to investigate variation in toxin contents. the venoms contained identical major toxin components, although in different relative concentrations. the venom collected separately from the left and right glands of individual snakes were virtually the same as judged by rp-hp ... | 1992 | 1595079 |
| structural analysis and comparison of cobrotoxin and cardiotoxins by near-ir fourier transform raman spectroscopy. | venom toxins were isolated from formosan cobra (naja naja atra) by cation-exchange chromatography. the near-ir ft-raman analytical method has been applied to the characterization and classification of the toxin components in their lyophilized forms. structural analysis and comparison of various purified toxin fractions were made with respect to their amino acid compositions and near-ir fourier-transform raman spectra. the results indicate that the major secondary structure of cobra toxins includ ... | 1992 | 1610379 |
| kinetics of the hydrolysis of micellar substrates catalyzed by snake venom phospholipases a2. | effects of ca2+ on the kinetic parameters for the hydrolysis of mixed micelles of 1,2-dipalmitoyl-sn-glycero-3-phosphorylcholine (dic16pc) with triton x-100, catalyzed by a cobra (naja naja atra) (group i) and a habu (trimeresurus flavoviridis) (group ii) pla2s, were studied and compared with the results reported for other group i and ii enzymes. the substrate bindings to group i enzymes were independent of the ca2+ binding, whereas the substrate bindings to group ii enzymes were facilitated mor ... | 1992 | 1569045 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| immunochemical cross-reactivity of neurotoxic phospholipase a2 enzymes from indian cobra (naja naja naja) venom using polyclonal antibodies. | rabbit antibodies were prepared against purified phospholipase a2 (nn-xia-pla2) from indian cobra (naja naja naja) venom. the pla2 has haemolytic, neurotoxic, myotoxic, cytotoxic and oedema-inducing activities apart from the catalytic activity. the immunological cross-reactivity of structurally similar neurotoxic pla2s was investigated using enzyme-linked immunosorbent assay (elisa) and immunodiffusion. anti-nn-xia-pla2 igg cross-reacted with other purified neurotoxic pla2s from the same venom. ... | 1993 | 7505490 |
| 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 |
| 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 |
| [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 |
| 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 |
| 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 |
| 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 |
| 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 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| [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 |