Publications

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
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
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
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
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
[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
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
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
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
effect of nonapeptide fragments of uteroglobin and lipocortin i on oedema and mast cell degranulation.	the anti-inflammatory action of nonapeptide fragments of uteroglobin or lipocortin i known as antiflammins, was tested in the carrageenan or phospholipase a2 rat paw oedema model. the development of carrageenan-induced oedema in rats was significantly inhibited during the early and late phases of the oedema by the local administration of antiflammins 1 and 2. however, the peptides were not able to inhibit phospholipase a2-induced oedema. the time course of the anti-oedematous activity of nonapep ...	1994	7535228
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
[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
cdna and protein sequences coding for the precursor of phospholipase a2 from taiwan cobra, naja naja atra.	the cdna sequence encoding phospholipase a2 (pla2) was determined by analysis of polymerase-chain-reaction (pcr) product amplified from total cdna mixture which had been constructed from the poly(a)+rna of venom glands obtained from taiwan cobras. two oligonucleotide segments corresponding to the 5'- and 3'-noncoding regions of sea-snake pla2 gene were used as primers for pcr-amplified reaction. plasmids of transformed e. coli strain jm109 containing amplified pla2 cdna were purified and prepare ...	1994	7521702
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
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
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
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
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
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 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
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
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
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
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
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 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
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
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 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
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
the three-dimensional nmr solution structure of α-cobratoxin at ph 7.5 and conformational differences with the nmr solution structure at ph 3.2.	abstract the 3d solution structure of α-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 φ dihedral angle restraints deduced from j- coupling data. the generated structures are well defined with root mean square deviations from a geometrical mean s ...	1994	22671905
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
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
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
[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
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
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
photolabeling reveals the proximity of the alpha-neurotoxin binding site to the m2 helix of the ion channel in the nicotinic acetylcholine receptor.	a photoactivatable derivative of neurotoxin ii from naja naja oxiana containing a 125i-labeled p-azidosalicylamidoethyl-1,3'-dithiopropyl label at lys-25 forms a photo-induced cross-link with the delta subunit of the membrane-bound torpedo californica nicotinic acetylcholine receptor (achr). the cross-linked radioactive receptor peptide was isolated by reverse-phase hplc after tryptic digestion of the labeled delta subunit. the sequence of this peptide, delta-(260-277), and the position of the l ...	1995	7543679
[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
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
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
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
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
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
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
inhibition of protein kinase c by snake venom toxins: comparison of enzyme inhibition, lethality and hemolysis among different cardiotoxin isoforms.	cardiotoxins, neurotoxins and phospholipase a2 (pla2) are three major classes of toxic components present in the taiwan cobra, naja naja atra of the elapidae family. cardiotoxins (or called cytotoxins), a group of major polypeptides of around 60 amino-acid residues present abundantly in the elapid family of snakes, comprise about 45-55% of the crude venom of taiwan cobra. in contrast to another prominent group of structurally similar neurotoxins with well-established acetylcholine receptors and ...	1995	7549929
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
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
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
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
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
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
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
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
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
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
no role for enzymatic activity or dantrolene-sensitive ca2+ stores in the muscular effects of bothropstoxin, a lys49 phospholipase a2 myotoxin.	the role of low levels of phospholipase a2 (pla2) activity and intracellular ca2+ stores in the pharmacological action of bothropstoxin (bthtx), a myotoxic lys49 pla2 homologue isolated from the venom of bothrops jararacussu, was investigated. we examined the muscular effects of bthtx in the mouse diaphragm and its pla2 activity in radiolabeled human and rat primary cultures of skeletal muscle. although it is a lys49 pla2 homologue, bthtx had a low, but easily detectable, level of enzymatic acti ...	1995	8744987
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
presynaptically acting snake venom phospholipase a2 enzymes attack unique substrates.	synaptosomes were incubated with bovine serum albumin (bsa) to examine whether the presynaptic action of snake venom phospholipase a2 (pla2) toxins is due either to the release of fatty acids resistant to extraction by bsa or to the liberation of a specific fatty acid type. in the presence of bsa (0.5% or 1.0%) two pla2 enzymes from naja naja atra and naja naja kaouthia snake venoms that do not have a predominant presynaptic action at the neuromuscular junction (ps-) did not stimulate acetylchol ...	1995	8866614
differential effects of snake venom phospholipase a2 neurotoxin (beta-bungarotoxin) and enzyme (naja naja atra) on protein kinases.	the phospholipase a2 (pla2) neurotoxin, beta-bungarotoxin (beta-butx), presynaptically alters acetylcholine release. we previously found that beta-butx inhibits protein phosphorylation in rat brain synaptosomes. this inhibition was not due to the inhibition of atp synthesis, the action of arachidonic acid (aa) metabolites, or the stimulation of phosphatase activities. a typical pla2 enzyme from naja naja atra (n. n. atra) venom also inhibited phosphorylation but with lesser potency than that of ...	1996	8937437
inhibition by multivalent cations of contraction induced by chinese cobra venom cardiotoxin in guinea pig papillary muscle.	the effects of cardiotoxin (ctx), purified from the venom of chinese cobra (naja naja atra) by a three-step chromatography, on the contractile responses of isolated guinea pig papillary muscle preparation and its antagonism by lanthanum ion (la3+) and divalent cations were examined. ctx induced tonic contraction following a transient augmentation of electrically evoked rhythmic contractions, which is similar to that seen in perfused heart preparation. multivalent cations, la3+, ca2+, mn2+ and mg ...	1996	8761008
chemical modification of methionines in a cobra venom cytotoxin differentiates between lytic and binding domains.	cytotoxin-iii from naja naja atra (ctx) was chemically modified at either or both of its two methionine residues: over 50% oxidation of methionine-26 occurred with a 1:1 molar ratio of chloramine-t:methionine; at a 5:1 molar ratio, methionine-26 was almost completely oxidized, while methionine-24 was modified only 26%; at a 10:1 molar ratio, both methionines were completely oxidized. each oxidized derivative demonstrated a lower toxicity toward t-cells than toward heart cells. conversely, bindin ...	1996	8806839
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
cobra venom cardiotoxin induces aggregation of washed rat platelets: dual effects of ca2+.	the effects of cardiotoxin isolated and purified from the venom of naja naja atra on the platelet aggregation were investigated using washed rat platelets prepared chromatographically. in the presence of 1 mm ca2+, cardiotoxin concentration-dependently induced aggregation of platelets. while extracellular ca2+ was necessary for the induction of aggregation by cardiotoxin, high concentration of ca2+ (e.g., 5 mm) prevented cardiotoxin-induced aggregation. cardiotoxin-induced platelet aggregation w ...	1996	8948018
specificity of polyunsaturated fatty acid release from rat brain synaptosomes.	release of specific polyunsaturated fatty acids for cell membranes may have a significant implication in biological function, considering the involvement of various fatty acids in cell signal transduction. in the present study, release of polyunsaturated fatty acids from rat brain synaptosomes by endogenous synaptosomal lipase activity was examined in comparison to that by cobra venom phospholipase a2 (naja naja naja). cobra venom phospholipase a2 (naja naja naja) preferentially hydrolyzed docos ...	1996	8729124
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
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
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
[effect of phospholipase a2 from naja naja oxiana venom on activity of na+,k+-atpase isoenzymes in rat brain].	the specific sensitivity of the isoforms of the rat brain na+,k(+)-atpase catalytic subunit to phospholipase a2 (pl a2) from naja naja oxiana venom has been estimated on the basis of changes in the two-component dose response curve of ouabain inhibition of na+,k(+)-atpase activity. moderate na+,k(+)-atpase inactivation of pl a2 is accompanied by a decrease of the apparent affinity for ouabain in comparison with the untreated enzyme without any significant changes in the isoform activity ratio in ...	1996	9011252
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
sir joseph fayrer md frs (1824-1907) indian medical service: snakebite and mortality in british india.	whilst professor of surgery at the calcutta medical college, dr fayrer studied all aspects of snake poisoning. his work, the thanatophidia of india being a description of the venomous snakes of the indian peninsula, with an account of the influence of their poison of life; and a series of experiments was published in 1872. collating information from official government records of death due to snakebite, fayrer recorded a mortality of 11,416 persons for the year 1869 in the presidency of bengal a ...	1996	8711752
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
inhibition of phospholipase a2 activities and some inflammatory responses by the marine product ircinin.	the marine product ircinin has been tested for its effects on secretory and cytosolic phospholipase a2 (pla2) activities in vitro as well as for inhibition of cellular functions in human neutrophils and inflammatory responses in mice. ircinin inhibited naja naja venom, human synovial recombinant, bee venom and zymosan-injected rat air pouch pla2 with ic50 values in the microm range, similar to those of the known inhibitor scalaradial. on the other hand, ircinin was less active on cytosolic pla2 ...	1996	8938669
antibody-mediated neutralization and binding-reversal studies on alpha-neurotoxins from micrurus nigrocinctus nigrocinctus (coral snake) venom.	an elisa based, non-radioactive acetylcholine receptor (achr) binding assay was used to detect the alpha-neurotoxins present in micrurus nigrocinctus nigrocinctus venom. sera from horses hyperimmunized against m. nigrocinctus venom contain antibodies which inhibit the binding of m. n. nigrocinctus alpha-neurotoxins to achr and reverse the binding of toxins already complexed with the receptor. this result supports the importance of using antivenom therapeutically in m. n. nigrocinctus envenomatio ...	1996	8730930
mechanism of action of beta-bungarotoxin, a presynaptically acting phospholipase a2 neurotoxin: its effect on protein phosphorylation in rat brain synaptosomes.	the snake venom phospholipase a2 neurotoxin, beta-bungarotoxin, acts presynaptically to alter acetylcholine release in both the peripheral and central nervous systems. in investigating the mechanism of this action, we found that beta-bungarotoxin inhibited phosphorylation of synapsin i, gap-43 and marcks in rat brain synaptosomes. this inhibition was not due to the inhibition of atp synthesis, action of arachidonic acid metabolites, or stimulation of phosphatase activities. furthermore, the acti ...	1996	9027977
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
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
the interaction of 8-anilinonaphthalene-1-sulfonate with his-47 of taiwan cobra phospholipase a2 perturbing by the binding of calcium ion.	the 8-anilinonaphthalene-1-sulfonate (ans) fluorescence intensity of ans-naja naja atra (taiwan cobra) phospholipase a2 (pla2) complex increased with the addition of ca2+, but the observed fluorescence enhancement markedly decreased after methylation of his-47 in pla2 molecule. however, the binding affinities of methylated pla2 for ans and ca2+ were similar to or even greater than those observed with native pla2. these results, together with the finding that ans electrostatically interacted with ...	1996	8799461
the essentiality of his-47 and the n-terminal region for the binding of 8-anilinonaphthalene-1-sulfonate with taiwan cobra phospholipase a2.	the binding of the apolar fluorescent dye 8-anilinonaphthalene-1-sulfonate (ans) to naja naja atra phospholipase a2 (pla2) as well as the enhancement of ans fluorescence of the pla2-ans complex decreased with increasing ph in a ph range from 3 to 9. these ph-dependent curves can be well interpreted as the perturbation of an ionizable group with pk value of 5.8, which was assigned as his-47 in the active site of pla2. the ionizable group with pk 5.8 was no longer observed after methylation of his ...	1996	8804572
a case study of cardiotoxin iii from the taiwan cobra (naja naja atra). solution structure and other physical properties.		1996	8726052
the structural elements of phospholipase a2 affecting the enhancement of 8-anilinonaphthalene-1-sulfonate fluorescence.	the binding of the apolar fluorescent dye 8-anilinonaphthalene-1-sulfonate (ans) to naja naja atra and bungarus multicinctus phospholipase a2 (pla2) as well as the ans fluorescence enhancement of pla2-ans complexes were ph-dependent. however, the ph-dependent curves and the ionizable groups perturbed by the binding of ans were essentially different for the two pla2 enzymes. methylation of his residue or removal of the n-terminal octapeptide made the ans fluorescence of pla2-ans complexes become ...	1996	8829622
enzymatic activities of some snake venoms from families elapidae and viperidae.	alkaline phosphomonoesterase, phosphodiesterase, l-amino acid oxidase, hyaluronidase, 5'-nucleotidase, arginine ester hydrolase, phospholipase a2 and proteinase activities were determined in eight snake venoms, including three from sea snake, of families elapidae and viperidae from pakistan. the species includes three sea snakes hydrophis cyanocinctus, enhydrina schsitosa, microcephalophis gracilis gracilis and two land snakes naja naja naja, bungarus caeruleus of family elapidae while three lan ...	1996	16414774
destabilisation of native tertiary structural interactions is linked to helix-induction by 2,2,2-trifluoroethanol in proteins.	the effect of 2,2,2-trifluoroethanol (tfe) on the structure of an all beta-sheet protein, cardiotoxin analogue 111 (ctx iii) from the taiwan cobra (naja naja atra) is studied. it is found that high concentrations (> 80% v/v) of tfe induced a beta-sheet to alpha-helix structural transition. it is found that in denatured and reduced ctx iii (rctx iii) helical conformation is induced even upon addition of low concentrations (> 10% v/v) of tfe. using three other proteins, namely, ribonuclease a (rna ...	1996	9024898
induction of helical conformation in all beta-sheet proteins by trifluoroethanol.	the effect of 2,2,2-trifluoroethanol (tfe) on the structure of five all beta-sheet proteins, isolated from the venom of the taiwan cobra (naja naja atra), is studied. in all the toxins used, it is observed that significant amount of alpha-helix is induced at higher concentrations of tfe. in all these proteins, the induction of helical conformation and disruption of the tertiary structure seem to occur simultaneously. the structural transitions induced by tfe in reduced and denatured protein appe ...	1996	9016415
the essentiality of calcium ion in the enzymatic activity of taiwan cobra phospholipase a2.	in order to address the mechanism whereby ca2+ wad crucial for the manifestation of the enzymatic activity of phospholipase a2 (pla2), four divalent cations were used to assess their influences on the catalytic activity and the fine structures of naja naja atra pla2. it was found that substitution of mg2+ or sr2+ for ca2+ in the substrate solution caused a decrease in the pla2 activity to 77.5% or 54.5%, respectively, of that in the presence of ca2+. however, no pla2 activity was observed with t ...	1996	9008293
modification of tyrosine-3 (63) and lysine-6 of taiwan cobra phospholipase a2 affects its ability to enhance 8-anilinonaphthalene-1-sulfonate fluorescence.	the tyr-3 (63) and lys-6 of naja naja atra phospholipase a2 (pla2) were modified with p-nitrobenzenesulfonyl fluoride and 4-chloro-3,5-dinitrobenzoate, respectively. although the ability of the lys-modified derivative to enhance the ans fluorescence was lower than that observed with native pla2, the ans-binding affinity of the lys-modified derivative was similar to that of the native enzyme. modifications on tyr-3 or/and tyr-63 of pla2 resulted in the complete loss of its ability to enhance the ...	1996	8896745
the role of acidic amino acid residues in the structural stability of snake cardiotoxins.	we have recently shown that membrane-related activities of cardiotoxin v from naja naja atra (ctx a5) are diminished at acidic ph although the overall beta-sheet structure of the molecule is maintained. in order to understand more about the mechanism of inactivation of ctx at acidic ph, we studied the effect of ph and denaturing reagents on the structural stability of ctx. we found, first, ph-induced structural transitions occurred in ctx a5 at two ph values as judged by the cd ellipticity aroun ...	1996	8703923
conformational change and inactivation of membrane phospholipid-related activity of cardiotoxin v from taiwan cobra venom at acidic ph.	the phospholipid binding activity of cardiotoxin v from naja naja atra (ctx a5) was studied by use of langmuir monolayers and found to exhibit ph-dependence in binding to phosphatidylcholine membrane with an apparent pka around 6.0. proton nmr investigation of the ctx a5 molecule in the presence of phosphatidylcholine micelles reveals a decrease in association of ctx a5 with membranes at low ph as a result of the protonation of his-4 near the membrane binding site of loop i region of ctx. the ph ...	1996	8703922
thermal denaturation of an all beta-sheet protein--identification of a stable partially structured intermediate at high temperature.	the thermal unfolding of an all beta-sheet protein, cardiotoxin analogue iii, from the taiwan cobra (naja naja atra) is studied at ph 2.0, 4.0 and 6.0. at ph 4.0, using circular dichroism and 1-anilino naphthalene-8-sulphonic acid (ans) fluorescence binding studies, a stable partially structured intermediate is detected at 90 degrees c.	1996	8739135
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
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
taxonomic changes and toxinology: systematic revisions of the asiatic cobras (naja naja species complex)	until recently, all asiatic cobra populations were regarded as belonging to one single species, naja naja. recent revisions have shown that there are in fact at least 10 full species of asiatic naja. in order to allow the existing literature to be reconciled with these recent discoveries, an interpretation of the older nomenclature is provided. problematic areas, especially concerning the species n. sumatrana and n. siamensis, are highlighted.	1996	8735239
[secondary structure and conformational heterogeneity of naja naja oxiana cytotoxin ii].	the proton resonances of cytotoxin ii from naja naja oxiana were sequentially assigned in 2d 1h nmr spectra for all of its 60 amino acid residues of both major and minor components of the spectra. the presence of the minor component was shown to be due to a conformational heterogeneity of the cytotoxin. the proton-deuterium exchange rates of amide groups were measured in 2h2o at a ph of 5.0 and at 10 degrees c. experimental data obtained (d-connectivities, h-nc alpha-h coupling constants and lon ...	1996	8929219
zanhasaponins a and b, antiphospholipase a2 saponins from an antiinflammatory extract of zanha africana root bark.	a meoh extract from z. africana was examined for topical antiinflammatory activity and proved to be active against arachidonic acid (aa) acute edema, 12-o-tetradecanoylphorbol 13-acetate (tpa)-induced chronic inflammation, and oxazolone delayed-type hypersensitivity in mice. the extract also showed significant inhibitory activity of naja naja phospholipase a2 when a polarographic method was used. two oleanane-type triterpene saponins, zanhasaponins a (1) and b (2), and the cyclitol pinitol (4), ...	1997	9392883
naja naja cobra bite.	most venomous snakes in the united states are of the crotalidae family. another family of snakes, the elapidae, are not so common, but their bites may be a threat to zoo keepers and persons who have exotic snakes as pets. because elapidae envenomation is not common, signs and symptoms of such envenomation may not be recognized. elapidae venom, because of a curare-like property, can produce respiratory compromise followed by death within 10 minutes. antivenin, cholinesterase inhibitors, and mecha ...	1997	9288976
effect of lipid composition on lipoprotein lipase activity measured by a continuous fluorescence assay: effect of cholesterol supports an interfacial surface penetration model.	the breakdown of normal substrates by lipases requires an interfacial binding step prior to hydrolysis. interfacial binding and subsequent hydrolysis will be affected by the lipid components and hence physical properties of the substrate surface. in order to investigate in detail the effect of lipid structure on the activity of lipoprotein lipase (lpl), triolein-containing emulsion particles of defined composition have been used as substrates. in addition, lipase activity has been measured using ...	1997	9032472
the action of taiwan cobra venom on methionine enkephalin: a useful assay for oligopeptidase content.	the pentapeptide methionine enkephalin is readily hydrolysed by the oligopeptidase activity contained in taiwan cobra (naja naja atra) venom. it is a significantly better substrate than the peptides previously used to identify the presence of this enzyme, but it retains many of the sequence characteristics shared by these other peptides. analysis of the manner of hydrolysis by means of high-performance liquid chromatography and electrospray mass spectrometry revealed the simultaneous actions of ...	1997	9248009