Publications

function of disintegrin-like/cysteine-rich domains of atrolysin a. inhibition of platelet aggregation by recombinant protein and peptide antagonists.	snake venom hemorrhagic metalloproteinase toxins that have metalloproteinase, disintegrin-like and cysteine-rich domains are significantly more potent than toxins with only a metalloproteinase domain. the disintegrin-like domains of these toxins differ from the disintegrin peptides found in crotalid and viperid venoms by the nature of their different disulfide bond structure and, in lieu of the disintegrins' signature arg-gly-asp (rgd) integrin binding sequence, there is an xxcd disulfide-bonded ...	1997	9148922
levels of therapeutic antivenin and venom in a human snakebite victim.	an enzyme-linked immunosorbent assay was used to measure the levels of therapeutic antivenin (antivenin [crotalidae] polyvalent, wyeth-ayerst) in serum and the levels of venom in the urine of a patient bitten by a western diamondback rattlesnake (crotalus atrox). serum and urine samples were taken on admission, during hospitalization, and during follow-up until 5 months after the bite. photographs were taken of the bite site on admission to the hospital and during follow-up. serum levels of ther ...	1996	8701381
native peptide inhibition. specific inhibition of type ii phospholipases a2 by synthetic peptides derived from the primary sequence.	the binding of low molecular weight type ii phospholipase a2 (ec) to membrane surfaces and hydrolysis of phospholipid are thought to involve the formation of a hydrophobic channel into which a single substrate molecule diffuses before cleavage. the floor and right side of the channel are provided by hydrophobic residues 2, 5, and 9 of an amphipathic amino-terminal helix. the channel is postulated to form via a conformational change in this helix and inward movement of a hydrophobic flap (residue ...	1996	8798633
amino acid sequence of a lectin-like protein from lachesis muta stenophyrs venom.	the primary structure of the lectin-like protein from lachesis muta stenophyrs venom was deduced from analysis of the n-terminus and the sequence of peptides obtained after digestion with trypsin, arg-c enzyme, staphylococcus aureus v8 protease and endoproteinase asp-n. peptides generated by cleavage of the lectin with cyanogen bromide and o-iodosobenzoic acid were also sequenced. comparison of the complete 135 amino acid residues sequence with those of the lectin from the venom of crotalus atro ...	1996	8843577
purification and partial characterization of (6-4) photoproduct dna photolyase from xenopus laevis.	the (6-4) photoproduct dna photolyase was detected in two vertebrate animals crotalus atrox (rattlesnake) and xenopus laevis (south african clawed toad). the enzyme was extensively purified from x. laevis and characterized. the highly purified enzyme is fluorescent with an excitation maximum at 420-440 nm and emission maximum at 460-480 nm. the photorepair action spectrum matches the fluorescence excitation spectrum with a 430 nm maximum.	1996	8881333
crystal structure of an acidic phospholipase a2 from the venom of agkistrodon halys pallas at 2.0 a resolution.	the crystal structure of acidic phospholipase a2 from the venom of agkistrodon halys pallas has been determined by molecular replacement at 2.0 a resolution to a crystallographic r-factor of 0.157. the overall structure of the molecule is very similar to those of other phospholipase a2 species of known structure. the catalytic site, the hydrophobic channel and the n-terminal region show greatest structural conservation. the ca(2+)-binding region has a conformation that resembles closely that of ...	1996	8636969
expression, activation, and processing of the recombinant snake venom metalloproteinase, pro-atrolysin e.	the expression in human embryonic kidney (hek 293) cells of the recombinant zymogen form (pro-) of the crotalus atrox hemorrhagic metalloproteinase, atrolysin e, is presented. the nascent protein is comprised of pre-, pro-, proteinase-, spacer-, and disintegrin domains. the biochemical characterization of the recombinant zymogen is described along with its activation by c. atrox crude venom and other hemorrhagic toxins. unlike the zymogen forms of the matrix metalloproteinases, pro-atrolysin e i ...	1996	8914925
interaction of plant lipids with 14 kda phospholipase a2 enzymes.	several structurally related plant lipids were isolated and their effect was assessed on the enzyme activity of group i (pancreatic and naja mocambique venom) and group ii (crotalus atrox venom) phospholipase a2 (pla2) enzymes, with labelled escherichia coli as an enzyme substrate. the neutral monogalactosyldiacylglycerol (mgdg) and negatively charged diacylglyceryl alpha-d-glucuronide (dgga) did not influence the enzyme activity of either group. digalactosyldiacylglycerol (dgdg), another unchar ...	1996	8947472
zinc (zn2+) binds to and stimulates the activity of group i but not group ii phospholipase a2.	phospholipase a2 plays an important part in the generation of inflammatory lipid mediators and so it is of major interest to understand functional distinctions between structurally similar forms of phospholipase a2. in the present study, the influence of zinc (zn2+) on the activity of group i and group ii phospholipase a2 was examined in vitro. it appeared that zn2+ (0.04-1 x 10(-3)m) increased group i phospholipase a2 activity from porcine pancreas and rat lung whereas the activity of group ii ...	1996	8979149
the hemorrhagin catrocollastatin inhibits collagen-induced platelet aggregation by binding to collagen via its disintegrin-like domain.	catrocollastatin, a 50 kda snake venom protein purified from crotalus atrox, specifically inhibits platelet-collagen adhesion and collagen-induced aggregation. catrocollastatin is composed of an n-terminal domain, a metalloproteinase domain, a disintegrin-like domain and a cysteine-rich c-terminal domain. the present studies show that catrocollastatin exerts its effect by binding to collagen. based on the amino acid sequence and homology analysis, a cyclic oligopeptide corresponding to a conserv ...	1996	8645248
structural correlates of speed and endurance in skeletal muscle: the rattlesnake tailshaker muscle	the western diamondback rattlesnake crotalus atrox can rattle its tail continuously for hours at frequencies approaching 90 hz. we examined the basis of these fast sustainable contractions using electromyography, data on oxygen uptake and the quantitative ultrastructure of the tailshaker muscle complex. the tailshaker muscle has no apparent unique structures; rather, the relative proportions of the structures common to all skeletal muscles appear to be present (1) to minimize activation, contrac ...	1996	9317944
atroxase--a fibrinolytic enzyme isolated from the venom of western diamondback rattlesnake. isolation, characterization and cloning.		1996	8726058
kinetic and pharmacologic characterization of phospholipases a2 from bothrops neuwiedii venom.	two phospholipases a2 (pla2) (ec 3.1.1.4) were purified from bothrops neuwiedii venom (isoenzymes p-1 and p-2). the molecular weights of p-1 and p-2 as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis were 15,000 and 16,200 and the isoelectric points were 4.8 and 4.6, respectively. the n-terminal 14-amino-acid sequences determined were asn-leu-val-gln-phe-glu-thr-leu-ile-met-met-ile-ala-gly and ser-leu-val-gln-phe-glu-thr-leu-ile-met-met-ile-ala-gly for p-1 and p-2, respect ...	1995	7726575
nucleotide sequence encoding the snake venom fibrinolytic enzyme atroxase obtained from a crotalus atrox venom gland cdna library.	atroxase, isolated from the venom of crotalus atrox (western diamondback rattlesnake), is a nonhemorrhagic protease which has fibrinolytic activity in vivo. the primary structure of atroxase was deduced from the cdna encoding the atroxase protein. the venom glands of crotalus atrox were used to prepare a cdna library. degenerate oligonucleotides were synthesized based on the partial amino acid sequence of atroxase and were used as primers in the polymerase chain reaction to amplify overlapping c ...	1995	7893150
atrolysins: metalloproteinases from crotalus atrox venom.		1995	7674933
structure of a calcium-independent phospholipase-like myotoxic protein from bothrops asper venom.	myotoxin ii, a myotoxic calcium-independent phospholipase-like protein isolated from the venom of bothrops asper, possesses no detectable phospholipase activity. the crystal structure has been determined and refined at 2.8 a to an r-factor of 16.5% (f > 3sigma) with excellent stereochemistry. amino-acid differences between catalytically active phospholipases and myotoxin ii in the ca(2+)-binding region, specifically the substitutions tyr28-->asn, gly32-->leu and asp49-->lys, result in an altered ...	1995	15299297
immunological studies on bah1 and bap1, two hemorrhagic metalloproteinases from the venom of the snake bothrops asper.	no immunological cross-reactivity was observed between bah1 and bap1, two hemorrhagic metalloproteinases isolated from b. asper venom, by gel immunodiffusion, western blotting and neutralization studies. cross-reactivity was detected with antisera against these toxins in several crotaline and viperine snake venoms by elisa, whereas no reactivity was observed with either antiserum against the venoms of bothrops nummifer, crotalus durissus terrificus, vipera russelli and several elapid venoms. ant ...	1995	8533144
molecular cloning and expression of catrocollastatin, a snake-venom protein from crotalus atrox (western diamondback rattlesnake) which inhibits platelet adhesion to collagen.	a 50 kda protein that inhibits platelet adhesion to collagen has been isolated from snake venom of crotalus atrox (western diamondback rattlesnake) and has been named 'catrocollastatin'. the cdna cloning of catrocollastatin has been accomplished. a full-length cdna of 2310 bp with an open reading frame between nucleotides 51 and 1880 was obtained. the deduced amino acid sequence consists of 609 amino acids. the cdna-predicted amino acid sequence is highly similar to that of haemorrhagic metallop ...	1995	7733877
the effect of cleavage by a crotalus atrox alpha-proteinase fraction on the properties of c1-inhibitor.	the effect of cleavage of c1-inhibitor at pro36 by a crotalus atrox alpha-proteinase fraction on the properties of this serpin was studied. this truncated c1-inhibitor (des 1-36) was fully active as an inhibitor of kallikrein, beta-factor xiia, and c1s, and modulated the functions of c1 in a normal manner. also, the half-life of the truncated protein in the circulation of rabbits, both alone and in complex with c1, was not altered. these results show that shock-like symptoms caused by c. atrox e ...	1995	7778129
coccidian parasites (apicomplexa) from snakes in the southcentral and southwestern united states: new host and geographic records.	four hundred thirty-five leptotyphlopid, colubrid, elapid, and viperid snakes were collected from various localities in arkansas, new mexico, oklahoma, and texas, and their feces were examined for coccidian parasites. of these, 131 (30%) were passing oocysts or sporocysts of at least 1 coccidian; 88 (67%) of the infected snakes had only 1 species of coccidian when they were examined. aquatic and semiaquatic snakes accounted for 48% of the infections, whereas strictly terrestrial snakes comprised ...	1995	7876980
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
rattlesnake bite complications in 19 children.	the western diamondback rattlesnake, crotalus atrox, is responsible for the majority of snakebites in sonora, mexico. we report 19 cases of children who were attacked by these snakes. most of the rattlesnake attacks occurred in rural areas during the summer. the children's ages ranged from one to 15 years. the lower extremities, especially the legs, were most often bitten. the signs and symptoms presented by these patients included: pain, edema, limitation of motion, ecchymosis, bleeding and nec ...	1994	8177804
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
inhibition of hemorrhagic activities of various snake venoms by purified antihemorrhagic factor obtained from japanese habu snake.	the ability of purified antihemorrhagic factor isolated from the serum of japanese habu (trimeresurus flavoviridis) was tested on 17 snake venoms to inhibit their hemorrhagic activity. the factor strongly inhibited that of the venoms of crotalus horridus horridus and vipera latastei gaditana in addition to that of the homologous (t. flavoviridis) venom. hemorrhagic activity of agkistrodon halys blomhoffi, agkistrodon contortrix contortrix, bothrops atrox asper and crotalus atrox venoms was also ...	1994	8016857
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
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
c-type galactoside-binding lectin from bothrops jararaca venom: comparison of its structure and function with those of botrocetin.	a ca(2+)-dependent type (c-type) galactoside-binding lectin was purified from venom of the snake bothrops jararaca by thiodigalactoside-sepharose affinity column chromatography. b. jararaca lectin is a disulfide-linked homodimer composed of 14-kda subunits. the n-terminal 55-residue amino acid sequence was determined and appeared to belong to the animal c-type lectin family. this 55-residue sequence showed 37% identity with botrocetin, an exogenous von willebrand factor modulator purified from t ...	1994	8311467
effect of crotalus atrox venom on sodium transport across the frog skin (39885).		1994	302948
the (dd)e complex is maintained by a composite fibrin polymerization site.	the (dd)e complex is the major cross-linked fibrin degradation fragment. structural components required for maintenance of the (dd)e complex were examined in order to better understand clot structure and the contribution of specific polypeptide chain segments in the process of polymerization. first, the (dd)e complex was reversibly dissociated by peptides derived from the alpha-chain nh2-terminus of fibrin having a minimal sequence of gpr (alpha 17-19). in addition, the complex was partially dis ...	1994	7524657
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
cdna sequences for four snake venom metalloproteinases: structure, classification, and their relationship to mammalian reproductive proteins.	presented here are four new cdna sequences for hemorrhagic metalloproteinases from crotalus atrox venom, hemorrhagic toxins a, b, c, and d. comparison of the translated open reading frames to the mature protein sequences gives evidence for post-translational processing at both the amino and carboxyl termini. this comparison is also the basis for a new classification system for these precursors, based on their different sizes. protein sequences in the zymogen region support the hypothesis of a cy ...	1994	8311451
structural interaction of natural and synthetic inhibitors with the venom metalloproteinase, atrolysin c (form d).	the structure of the metalloproteinase and hemorrhagic toxin atrolysin c form d (ec 3.4.24.42), from the venom of the western diamondback rattlesnake crotalus atrox, has been determined to atomic resolution by x-ray crystallographic methods. this study illuminates the nature of inhibitor binding with natural (< glu-asn-trp, where < glu is pyroglutamic acid) and synthetic (sch 47890) ligands. the primary specificity pocket is exceptionally deep; the nature of inhibitor and productive substrate bi ...	1994	8078901
organization and chromosomal location of repetitive dna sequences in three species of squamate reptiles.	repetitive dna sequences were isolated from the genomes of species representing three major clades of squamate reptiles. a repetitive sequence (cn4c7) was isolated from the new mexican whiptail lizard, cnemidophorus neomexicanus. this sequence is distributed throughout the chromosomes, but is more concentrated in the telomeric region. cn4c7 also hybridizes to the chromosomes of other cnemidophorus. some evidence was found for concerted evolution of this repeat in hybrid unisexual lineages. in th ...	1994	7921642
isolation of multiple isoforms of alpha-fibrinogenase from the western diamondback rattlesnake, crotalus atrox: n-terminal sequence homology with ancrod, an antithrombotic agent from malayan viper.	three fibrinogenolytic proteases from the rattlesnake (crotalus atrox) venom were isolated and purified from multiple-step chromatographies including ion-exchange chromatography, gel permeation and reversed-phase hplc. the fractions were shown to be homogeneous as judged by sds-gel electrophoresis. in vitro, they also showed a high and specific proteolytic activity against alpha-chains of fibrinogen molecules. further characterization of these purified fractions with fibrinogenase activity indic ...	1994	8024586
purification and characterization of a coagulant enzyme, okinaxobin ii, from trimeresurus okinavensis (himehabu snake) venom which release fibrinopeptides a and b.	a coagulant enzyme, okinaxobin i, which was purified from trimeresurus okinavenis (himehabu snake) venom, released specifically fibrinopeptide b from fibrinogen to form fibrin clots. in the present study, its isozyme denoted as okinaxobin ii has been purified to homogeneity from the same venom by chromatographies on sephadex g-100, cm-toyopearl 650m, and fplc mono-q columns. differently from okinaxobin i, okinaxobin ii specifically cleaved fibrinopeptides a and b from fibrinogen similarly as fou ...	1994	7725319
hemorrhagic metalloproteinases from snake venoms.	one of the more significant consequences of crotalid envenomation is hemorrhage. over the past 50 years of investigation, it is clear that the primary factors responsible for hemorrhage are metalloproteinases present in the venom of these snakes. the biochemical basis for their activity is the proteolytic destruction of basement membrane and extracellular matrix surrounding capillaries and small vessels. these proteinase toxins may also interfere with coagulation, thus complementing loss of bloo ...	1994	7972338
spreading of platelets on fibrin is mediated by the amino terminus of the beta chain including peptide beta 15-42.	we have investigated the adhesion and spreading of platelets on polymerized fibrin of varying structure to identify sites that mediate these interactions. fibrin was prepared with thrombin to remove both fibrinopeptide a (fpa) and fibrinopeptide b (fpb) and with reptilase or agkistrodon contortrix thrombin-like enzyme (acte) to selectively remove fpa or fpb, respectively. residual fibrin-bound enzymes were inhibited with d-phenylalanyl-l-prolyl-l-arginyl chloromethyl ketone (ppack). platelet adh ...	1993	8481515
cytotoxicity of crotoxin on murine erythroleukemia cells in vitro.	the cytotoxic effect of crotoxin, a heterodimeric phospholipase a2 from the venom of crotalus durissus terrificus, was examined on murine erythroleukemia cells in vitro. crotoxin cytocidal effect on cell growth had an ec50 of approximately 0.1-0.2 microm (3.0-5.0 micrograms/ml) in serum-free medium. cytotoxicity was independent of cell growth since both quiescent and proliferating cells had similar sensitivities to the toxin. dissociation of the crotoxin complex and phospholipase a2 activity of ...	1993	8349431
an examination of structural interactions presumed to be of importance in the stabilization of phospholipase a2 dimers based upon comparative protein sequence analysis of a monomeric and dimeric enzyme from the venom of agkistrodon p. piscivorus.	phospholipases a2 may exist in solution both as monomers and dimers, but enzymes that form strong dimers (kd approximately 10(-9) m) have been found, thus far, only in venoms of the snake family crotilidae. the complete amino acid sequences of a basic monomeric and an acidic dimeric phospholipase a2 from agkistrodon piscivorus piscivorus (american cottonmouth water moccasin) venom have been determined by protein sequencing methods as part of a search for aspects of structure contributing to form ...	1993	8489705
three-dimensional structures of human phospholipase a2 from pancreas and synovial fluid by model building.	three-dimensional structures of the enzyme phospholipase a2 (pla2) from human pancreas and from human synovial fluid were constructed by model building based on high-resolution x-ray crystallographic structures and homology considerations. the structure of the human pancreatic pla2 was based on the x-ray structure of the highly homologous bovine pancreatic pla2 (type i) by amino acid substitution and modification of the c-terminal part followed by geometry relaxation. the structure of the pla2 f ...	1993	8399996
experimental transmission of caryospora bigenetica wacha et christiansen, 1982 (apicomplexa: eimeriidae) from a rattlesnake, crotalus atrox, to rodents and pigs.	caryosporan oocysts were found in the feces of a diamond rattlesnake, crotalus atrox, kept in zoo ustí nad labem, czech republic. comparison of oocyst structure with hitherto described caryospora species from snakes revealed that they were caryospora bigenetica wacha et christiansen, 1982. the rattlesnake, crotalus atrox, represents a new host for c. bigenetica. the common vole (microtus arvalis) and gerbil (meriones unguiculatus) were successfully infected with a mixture of c. bigenetica oocyst ...	1993	8244210
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
otoconin-22, the major protein of aragonitic frog otoconia, is a homolog of phospholipase a2.	otoconia are composites of proteins and inorganic crystals formed in the peripheral portion of the vestibular system of vertebrates. they add mass to the extracellular otoconial membrane, thereby increasing its deflection during linear acceleration. this added mass increases the sensitivity of the underlying sensory maculae. otoconia provide a promising system to decipher the interaction of protein and mineral during the growth and maintenance of biominerals. we have purified the major protein o ...	1993	8494877
comparison of the immunogenicity and antigenic composition of ten central american snake venoms.	the immunological reactivity of five crotaline antivenoms for the venoms of ten costa rican snakes was determined. venoms from bothrops asper, b. godmani, b. lateralis, b. nasutus, b. ophryomegas, b. schlegelii, b. nummifer, b. picadoi, crotalus durissus durissus and lachesis muta stenophrys were separated by sds-page, transferred to cellulose nitrate membrane and reacted against five different antivenoms. antisera used in the immunoblotting were prepared in rabbits to the crotaline venoms from ...	1993	8212043
direct cytotoxic effects of hemorrhagic toxins from crotalus ruber ruber and crotalus atrox on human vascular endothelial cells, in vitro.		1993	8121324
effects of constriction bands on rattlesnake venom absorption: a pharmacokinetic study.	to determine whether the use of a constriction band alters systemic absorption of rattlesnake venom in pigs and whether constriction band use alters local swelling.	1992	1514719
structure of acidic phospholipase a2 for the venom of agkistrodon halys blomhoffii at 2.8 a resolution.	the crystal structure of acidic phospholipase a2 from the venom of agkistrodon halys blomhoffii has been determined by molecular replacement methods based on the known structure of crotalus atrox pla2, a same group ii enzyme. the overall structures, except the calcium-binding regions, are very similar to each other. a calcium ion is pentagonally ligated to two carboxylate oxygen atoms of asp-49 and each carbonyl oxygen atoms of tyr-28, gly-30 and ala-31. a reason why the former enzyme functions ...	1992	1567418
isolation from opossum serum of a metalloproteinase inhibitor homologous to human alpha 1b-glycoprotein.	fractionation of opossum (didelphis virginiana) serum with (nh4)2so4, followed by chromatography on deae-sepharose, phenyl-sepharose, and mono q hr 5/5, has resulted in the isolation in homogeneous condition of a metalloproteinase inhibitor designated oprin (opossum proteinase inhibitor). oprin is a single-chain glycoprotein (26% carbohydrate) with an estimated mr = 52,000, pi = 3.5, and e(1%/1 cm) = 11. oprin inhibited snake venom metalloproteinases, but showed no activity on venom serine prote ...	1992	1731898
endothelial cell spreading on fibrin requires fibrinopeptide b cleavage and amino acid residues 15-42 of the beta chain.	adhesion and spreading of cultured human umbilical vein endothelial cells on fibrin surfaces of varying structure were characterized to understand better the interactions occurring between endothelium and fibrin at sites of vascular injury. fibrin prepared with reptilase, which cleaves only fibrinopeptide a from fibrinogen, and fibrin prepared with thrombin, which cleaves both fibrinopeptide a and fibrinopeptide b, equally supported endothelial cell adhesion. in contrast, only fibrin made with t ...	1992	1541676
sequence determination and characterization of a phospholipase a2 isozyme from trimeresurus gramineus (green habu snake) venom.	in addition to phospholipase a2-i (pla2-i) reported previously (oda et al., 1991, toxicon 29, 157), a new pla2 named pla2-ii was isolated from trimeresurus gramineus (green habu snake) venom, and its amino acid sequence was determined by sequencing the native protein and the peptides produced by enzymatic (achromobacter protease i and clostripain) cleavages of the carboxamidomethylated derivative of the protein. the protein consisted of 122 amino acid residues and his-47, asp-48, and asp-98 whic ...	1992	1485333
evaluation of four different immunogens for the production of snake antivenoms.	four different immunogens were used to produce polyvalent antivenom in rabbits to the venoms of bothrops atrox, crotalus atrox, crotalus adamanteus and crotalus durissus terrificus. the immunogens were: (1) unfractionated mixture of the four crude venoms, and three fractions of the mixture as follows, (2) hplc gel filtration high (> 50,000) mol. wt fraction, (3) hplc gel filtration medium (14,000-50,000) mol. wt fraction, and (4) hplc gel filtration low (< 14,000) mol. wt fraction. the resultant ...	1992	1485332
comparison of the purity and efficacy of affinity purified avian antivenoms with commercial equine crotalid antivenoms.	antivenoms were raised in laying hens by repeated immunizations with detoxified crotalid snake venoms and purified from egg yolks by affinity chromatography. while the affinity purified avian antivenoms were essentially pure igg, commercial equine (wyeth) and w.h.o. international reference antivenoms (trimeresurus flavoviridis) contained several non-immunoglobulin contaminants. in standard mouse protection assays, the purified avian crotalus atrox and t. flavoviridis antivenoms were 6.3 and 2.0 ...	1992	1440638
evidence that a secondary binding and protecting site for factor viii on von willebrand factor is highly unlikely.	a binding domain for factor viii (f.viii) has been previously identified on the n-terminal portion of human von willebrand factor (vwf) subunit [amino acids (aa) 1-272]. in order to characterize other possible structures of vwf involved in its capacity to bind and to protect f.viii against human activated protein c (apc), we used a series of purified vwf fragments overlapping the whole sequence of the subunit. among those were fragments spiii (dimer; aa 1-1365), spii (dimer; aa 1366-2050) and sp ...	1992	1531749
[hydrolysis of 5'-phosphonates and nucleoside phosphates by phosphatases of various origin and human and calf serum].	the hydrolysis of 5'-phosphonates of 2'-deoxythymidine and its 3'-modified analogs, inhibiting the hiv reproduction, by the e. coli alkaline, calf intestine and human placenta phosphatases as well as by the crotalus atrox venom 5'-nucleotidase were studied. transformations of 5'-phosphonates of adenosine and its analogs during incubation with human and fetal calf blood sera were investigated. the nucleotide derivatives modified at the phosphate residue were not hydrolyzed by any of the phosphata ...	1992	1335121
citrate is a major component of snake venoms.	citrate has been identified as a major component of snake venoms by gas liquid chromatography and mass spectrometry. the venoms of bothrops asper, crotalus atrox, crotalus viridis viridis, crotalus adamanteus, sistrurus miliarius barbouri, crotalus horridus horridus, agkistrodon contortrix mokasen, agkistrodon contortrix contortrix and agkistrodon piscivorus piscivorus contain citrate at concentration levels which can serve as effective buffers. calcium, magnesium, zinc, iron, sodium and potassi ...	1992	1626327
structure-function relationship for the highly toxic crotoxin from crotalus durissus terrificus.	the three-dimensional structure of the highly toxic crotoxin from crotalus durissus terrificus was modelled based on sequence analysis and the refined structure of calcium-free phospholipase of crotalus atrox venom. small-angle x-ray scattering experiments were performed on aqueous solutions of crotoxin. the radial distribution function derived from these scattering experiments and the one calculated from the model structure are in good agreement. crotoxin consists of a basic and an acidic subun ...	1992	1425475
characterization of a protease with alpha- and beta-fibrinogenase activity from the western diamondback rattlesnake, crotalus atrox.	a metalloprotease from the rattlesnake crotalus atrox venom was isolated and purified from multiple-step chromatographies including anion-exchange chromatography, gel permeation and reversed-phase hplc. the fraction was shown to be homogeneous as judged by sds-gel electrophoresis. it also showed a high proteolytic activity against alpha- and beta-chains of fibrinogen molecules. further characterization of the purified fraction with fibrinogenase activity indicated that it is a single-chain prote ...	1992	1520324
sequence of a cdna clone encoding the zinc metalloproteinase hemorrhagic toxin e from crotalus atrox: evidence for signal, zymogen, and disintegrin-like structures.	the sequence of two overlapping cdna clones for the zinc metalloproteinase hemorrhagic toxin e (also known as atrolysin e, ec 3.4.24.44) from the venom gland of crotalus atrox, the western diamondback rattlesnake, is presented. the assembled cdna sequence is 1975 nucleotides in length and encodes an open reading frame of 478 amino acids. the mature hemorrhagic toxin e protein as isolated from the crude venom has a molecular weight of approximately 24,000 and thus represents the processed product ...	1992	1378300
isolation of a crotalase-like protease with alpha-fibrinogenase activity from the western diamondback rattlesnake, crotalus atrox.	venom toxins were isolated from rattlesnake (crotalus atrox) venom by cation-exchange chromatography. seven major fractions could be obtained by single-step ion-exchange chromatography with two fractions showing essentially apparent homogeneity by sds-gel electrophoresis. all fractions showed various extents of specific proteolytic activity against alpha- or beta-chains of fibrinogen molecules. further characterization of one of the purified fractions with alpha-fribrinogenase activity indicated ...	1992	1616487
external na+ is not required for ca2+ mobilization in platelets stimulated with rattlesnake lectin or alpha-thrombin.	the effects of extracellular sodium on platelet aggregation and calcium mobilization in platelets stimulated with either rattlesnake (crotalus atrox) lectin (rsl) or alpha-thrombin were compared. the absence of extracellular sodium had no effect on platelet aggregation or calcium mobilization in response to all levels of rsl tested. in contrast platelet aggregation was sodium-dependent in response to less than or equal to .2 units/ml alpha-thrombin. surprisingly, calcium mobilization occurred in ...	1991	1805450
polymerization site in the beta chain of fibrin: mapping of the b beta 1-55 sequence.	the formation of a fibrin clot occurs through binding of putative complementary sites, called fibrin polymerization sites, located in the nh2- and cooh-terminal domains of fibrin monomer molecules. in this study, we have investigated the structure of the nh2-terminal fibrin polymerization site by using fibrinogen-derived peptides and fragments. fibrinogen was digested with crotalus atrox protease iii, to two major molecular species: a mr 325,000 derivative (fg325) and a peptide of mr 5000. the p ...	1991	1988018
proteolytic digestion of non-collagenous basement membrane proteins by the hemorrhagic metalloproteinase ht-e from crotalus atrox venom.	hemorrhagic toxin e (ht-e), a metalloproteinase isolated from the venom of the western diamondback rattlesnake crotalus atrox, digests laminin and nidogen, both in their isolated forms and when present in a purified soluble complex. the only common site of cleavage by ht-e of isolated nidogen and nidogen when complexed with laminin is at amino acid residue 336 in the amino terminal domain. additionally, nidogen in complex with laminin is also cleaved at sites 322, 351 and 840 as determined by se ...	1991	1801753
effect of inadequate antivenin stores on the medical treatment of crotalid envenomation.	the case of a 27-y-old male with a serious crotalus atrox envenomation is presented. his medical care was compromised by the lack of readily available polyvalent crotalidae antivenin. an investigation of antivenin stocking by health care facilities in arizona was undertaken. failure to stock sufficient quantities of antivenin to initiate treatment of a single patient with a severe envenomation was found in 43.5% of urban hospitals, 41.2% of rural hospitals within 25 miles of another hospital, 52 ...	1991	1858308
monolayers of long chain lecithins at the air/water interface and their hydrolysis by phospholipase a2.	the behavior of phosphatidylcholine monolayers at the air/water interface was studied by measuring their surface isotherm, surface potential, surface viscosity, and rate of hydrolysis by the dimeric phospholipase a2 from the venom of crotalus atrox. the monolayers showed typical liquid-expanded behavior. in this phase, the surface potential was linearly dependent on surface concentration and extrapolated at zero concentration to a value characteristic of a liquid hydrocarbon/water interface. the ...	1991	1999420
complete primary structure of a galactose-specific lectin from the venom of the rattlesnake crotalus atrox. homologies with ca2(+)-dependent-type lectins.	the complete primary structure of a galactose-specific lectin contained in the venom of the rattlesnake, crotalus atrox, was determined. the lectin is composed of two covalently linked, identical subunits, each consisting of 135 amino acid residues. under physiological conditions the lectin proved to be highly aggregated. the venom lectin contained 9 half-cystines, 8 of which formed four intrasubunit disulfide bridges (cys3-cys14, cys31-cys131, cys38-cys133, and cys106-cys123), while cys86 was i ...	1991	1989986
antihemorrhagic factors from the blood serum of the western diamondback rattlesnake crotalus atrox.	several antihemorrhagic factors isolated from c. atrox serum are glycoproteins with mol. wt ranging from 65,000 to 80,000. the antihemorrhagic activity of these factors was stable at a ph range of 1.3-11.5 and at temperatures up to 85 degrees c, for 30 min. the isolated antihemorrhagins also neutralized the proteolytic activity of c. atrox venom, as tested with azocollagen and gelatin, and formed a complex with hemorrhagic toxin e isolated from the same venom. the neutralization capacity of the ...	1991	1656547
snake venom or antivenom induced urticaria.	an amateur herpetologist developed chills, diaphoresis and generalized urticaria 5 h after receiving antivenin (crotalidae) polyvalent (wyeth) for treatment of rattlesnake (crotalus atrox) envenomation. the patient had been bitten 8 mo earlier by a copperhead (agkistrodon contortrix mokeson) resulting in minimal envenomation. he also had been skin testing himself for 6 mo with both diluted crotalus atrox venom and antivenin (crotalidae) polyvalent (wyeth) to determine how sensitive he was to ant ...	1991	1858314
effects of ph and calcium ion on self-association properties of two dimeric phospholipases a2.	the monomer-dimer equilibria of the dimeric phospholipases a2 from crotalus atrox and agkistrodon piscivorus piscivorus venoms were examined chromatographically as a function of ph and in the presence versus absence of the essential cofactor, calcium ion. at neutral ph without calcium, the subunits of both enzymes reequilibrated sufficiently slowly that dimer and monomer were separated by size exclusion chromatography. at ph 4.2 and lower, the dimers underwent rapid dissociation and reassociatio ...	1991	1885568
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
proteolysis of interleukin-2, interferon and immunoglobulin by venoms.	limited proteolysis by venoms was analysed by the cleaved peptide band(s) in sds-polyacrylamide gel electrophoresis. the venom from crotalus atrox degraded interferon, interleukin-2, igg, igm, and a crude form of acetyl cholinesterase but had no effect on iga. although the venom from androctonus australis did not exert appreciable proteolysis on any of the immunoglobulins it had potent proteolytic activities against interferon and interleukin-2. the venom from vespula maculifrons had only a mino ...	1991	1724747
adaptability of restrained molecular dynamics for tertiary structure prediction: application to crotalus atrox venom phospholipase a2.	in order to assess the adaptability and/or applicability of the restrained molecular dynamics (rmd) simulation for building a possible tertiary structure of a protein from the x-ray crystal structure of a family reference protein, the tertiary structure prediction of crotalus atrox venom phospholipase a2 (pla2) was attempted based on the x-ray crystal structure of bovine pancreatic pla2. for the formation of secondary and tertiary structures from the fully extended starting structure, the rmd si ...	1991	1881869
the hypotensive activity of crotalus atrox (western diamondback rattlesnake) venom: identification of its origin.	viperidae snakes belonging to the genus crotalus, subfamily crotalinae, include the species durissus terrificus, durissus durissus, adamanteus, atrox, cerastes, horridus, molossus, scutulatus, viridis and others. all of them, except for the first 2, are found in north america. crotalus atrox, or diamondback rattlesnakes, live in the southwest united states and in mexico. this paper describes the fractionation of c. atrox venom in order to isolate and identify its hypotensive agents.	1991	2035756
specific binding of crotoxin to brain synaptosomes and synaptosomal membranes.	crotoxin, the presynaptic neurotoxin from crotalus durissus terrificus, was iodinated and used to demonstrate high affinity, specific binding to guinea-pig (cavia porcellus) brain synaptosomes and synaptosomal membrane fragments. 125i-crotoxin binding to the membrane fragments displays two binding plateaus, (kd1 = 4 nm and kd2 = 87 nm, bmax1 = 2 and bmax2 = 4 pmoles/mg membrane protein), but binding to whole synaptosomes revealed only one plateau (kd = 2 nm and bmax = 5 pmoles/mg membrane protei ...	1991	1949068
an indirect haemolytic assay for assessing antivenoms.	dilutions of antivenom, venom, human erythrocytes and a phosphatidylcholine suspension, were incubated for 30 min at 37 degrees c. after centrifugation, the liberated haemoglobin was measured spectrophotometrically. the assay was used to assess an ovine antivenom against the venom from the south american rattlesnake, crotalus durissus terrificus, and an equine wyeth antivenin (crotalidae, polyvalent). the ovine antivenom was more than five times as effective as the equine product. it also neutra ...	1991	1949062
immunological properties of the fibrinolytic enzyme (fibrolase) from southern copperhead (agkistrodon contortrix contortrix) venom and its purification by immunoaffinity chromatography.	an antibody to the fibrinolytic enzyme in southern copperhead venom was produced by immunizing rabbits with chromatographically purified enzyme. the antibody was purified from rabbit blood by ammonium sulfate fractionation and protein-a affinity chromatography. the purified antibody reacted only with the fibrinolytic enzyme in southern copperhead venom as demonstrated by immunodiffusion and immunoelectrophoresis. western immunoblotting revealed that several snake venoms, including agkistrodon pi ...	1991	1926169
structure of recombinant human rheumatoid arthritic synovial fluid phospholipase a2 at 2.2 a resolution.	phospholipases a2 (pla2s) may be grouped into distinct families of proteins that catalyse the hydrolysis of the 2-acyl bond of phospholipids and perform a variety of biological functions. the best characterized are the small (relative molecular mass approximately 14,000) calcium-dependent, secretory enzymes of diverse origin, such as pancreatic and venom pla2s. the structures and functions of several pla2s are known. recently, high-resolution crystal structures of complexes of secretory pla2s wi ...	1991	2062381
amino acid sequence of a phospholipase a2 from the venom of trimeresurus gramineus (green habu snake).	two phospholipases a2, named phospholipases a2-i and a2-ii, were purified to homogeneity from the venom of trimeresurus gramineus (green habu snake). the complete amino acid sequence of phospholipase a2-i was determined by sequencing the native protein and the peptides produced by enzymatic (achromobacter protease i, clostripain, and chymotrypsin) and chemical (hydroxylamine) cleavages of the s-pyridylethylated derivative of the protein. the protein consisted of 122 amino acid residues and was s ...	1991	2048135
neutralization of kinin-releasing enzymes of crotalid venoms by monospecific and polyspecific antivenoms.	the amounts of kinin-releasing enzymes in the venoms of crotalus atrox, crotalus adamanteus, crotalus scutulatus scutulatus and agkistrodon piscivorus piscivorus were measured by determining the amounts of kinin released from a sheep kininogen substrate by means of a specific radioimmunoassay. four monospecific and two commercial polyspecific antivenom igg samples were tested for their ability to reduce the kinin-releasing activities of the four crotalid venoms measured in vitro. all of the anti ...	1991	1926178
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
molecular dynamics simulations of phospholipases a2.	an extensive molecular dynamics study of phospholipases a2 from pancreatic bovine and crotalus atrox venom has shown that the well-conserved homologous core of the phospholipases a2, including the so called catalytic network, is very stable during the course of the calculations. the fluctuations which occur are located in segments which have significantly different three-dimensional conformations in the two phospholipases a2 studied, suggesting that a particularly stable core conformation gives ...	1990	2075191
rattlesnake and scorpion antivenoms from the egg yolks of immunized hens.	antivenoms used to treat poisonous bites and stings are usually derived from horse sera. consequently, they contain horse immunoglobulins, which frequently cause complement mediated side effects, and other proteins that can cause serum sickness and, occasionally, anaphylactic shock. here we describe a new, avian source of antivenoms that precludes these complications, and an efficient and gentle means for preparing antivenoms composed solely of venom-specific antibodies. we demonstrate that anti ...	1990	1366776
dimeric character of a basic phospholipase a2 from cobra venom: experimental and modelling study.	when it is gel filtered on sephadex in the absence of calcium ions, basic phospholipase a2 from naja nigricollis venom elutes as a dimer. in order to study the possibility of this dimerization from a structural point of view, three-dimensional models of both monomeric and dimeric n. nigricollis phospholipases a2 have been graphically built on the basis of homologies with the phospholipases a2 from pancreatic bovine and crotalus atrox venom. the building of a dimeric model is made possible by the ...	1990	2075192
isoforms of a highly specific b beta-chain fibrinogenase from the venom of crotalus atrox: preliminary observations.	three variants of a crotalus atrox venom enzyme that cleaves primarily the arg42 - ala bond of the b beta-chain of human fibrinogen were separated by high-performance liquid chromatography and were shown by n-terminal sequence analysis to be amino acid isoforms. all are single-chain glycoproteins whose approximate molecular weights lie between 26,000 and 28,000. the isoenzymes also cleaved the a alpha-chain at arg491 - his, though much more weakly, with strengths for both bonds that varied among ...	1990	2133222
kinetics of the hydrolysis of mixed micelles of dipalmitoyllecithin with triton x-100 catalyzed by a phospholipase a2 from the venom of agkistrodon halys blomhoffii.	the ph dependence of kinetic parameters for the hydrolysis of mixed micelles of 1,2-dipalmitoyl-sn-glycero-3-phosphorylcholine (dic16pc) with triton x-100, catalyzed by the intact and the n-terminal alpha-nh2-modified phospholipases a2 (pla2s) of agkistrodon halys blomhoffii, was studied at 25 degrees c and ionic strength 0.1 in the presence of saturating amounts of ca2+. the ph dependence of the kinetic parameters for the hydrolysis of monodispersed dic6pc, catalyzed by the modified enzyme, was ...	1990	2229006
structure of an engineered porcine phospholipase a2 with enhanced activity at 2.1 a resolution. comparison with the wild-type porcine and crotalus atrox phospholipase a2.	the crystal structure of an engineered phospholipase a2 with enhanced activity has been refined to an r-factor of 18.6% at 2.1 a resolution using a combination of molecular dynamics refinement by the gromos package and least-squares refinement by tnt. this mutant phospholipase was obtained previously by deleting residues 62 to 66 in porcine pancreatic phospholipase a2, and changing asp59 to ser, ser60 to gly and asn67 to tyr. the refined structure allowed a detailed comparison with wild-type por ...	1990	2254938
interaction of hemorrhagic metalloproteinases with human alpha 2-macroglobulin.	the interaction between four crotalus atrox hemorrhagic metalloproteinases and human alpha 2-macroglobulin was investigated. the proteolytic activity of the hemorrhagic toxins ht-c, -d, and -e against the large molecular weight protein substrates, gelatin type i and collagen type iv, was completely inhibited by alpha 2-macroglobulin. the proteolytic activity of ht-a against the same substrates was not significantly inhibited. each mole of alpha 2-macroglobulin bound maximally 2 mol of ht-e and 1 ...	1990	1692735
comparison of the immunogenicity and antigenic composition of several venoms of snakes in the family crotalidae.	crude venoms from the prairie rattlesnake (crotalus viridis viridis), the western diamondback rattlesnake (crotalus atrox), the eastern diamondback rattlesnake (crotalus adamanteus) and the timber rattlesnake (crotalus horridus horridus) were used to prepare monovalent antivenoms in rabbits. each of these four monovalent antivenoms was reacted against six different venoms using the technique of immunoblotting (western blot) to determine the relative immunogenicity of the four venoms and to compa ...	1990	2339435
kinetic and inhibition studies of phospholipase a2 with short-chain substrates and inhibitors.	the action of the phospholipases a2 (pla2s) from naja naja naja, naja naja atra, and crotalus atrox venoms as well as the enzyme from porcine pancreas on a number of short-chain, water-soluble substrates was studied. the inhibition of these enzymes by short-chain phosphonate- and thiophosphonate-containing phospholipid analogues was also examined. the kinetic patterns observed for the action of the venom pla2s on substrates containing phosphocholine head groups all deviated from a classical mich ...	1990	2383571
south american snake venom proteins antigenically related to bothrops asper myotoxins.	1. the presence of proteins antigenically related to bothrops asper myotoxins in various snake venoms, mainly from south america, was investigated by using polyclonal and monoclonal antibodies. 2. myotoxin-like components were detected in ten bothrops venoms from south america, and in the venoms of crotalus atrox (north america), trimeresurus flavoviridis (japan), and micrurus alleni (costa rica). 3. cross-reactive components detected in several bothrops venoms show a common subunit of 15-16 kda ...	1990	1710160
primary structure of a hemorrhagic metalloproteinase, ht-2, isolated from the venom of crotalus ruber ruber.	crotalidae and viperidae snake venoms contains several kinds of metalloproteinases which cause localized hemorrhage by direct action on blood vessel walls. we report here the entire amino acid sequence and the disulfide bridge locations of ht-2, one of the hemorrhagic toxins isolated from the venom of crotalus ruber ruber (red rattlesnake). the non-reduced protein was first cleaved at methionine residues to provide a set of 8 fragments, which covered the entire sequence of ht-2. the disulfide br ...	1990	2081731
the complete amino acid sequence of the high molecular mass hemorrhagic protein hr1b isolated from the venom of trimeresurus flavoviridis.	hemorrhage is a common occurrence in a victim bitten by crotalid and viperid snakes, and hemorrhagic components in these various venoms have been isolated and characterized. previously, we have shown that a low molecular weight hemorrhagic protein (hr2a, 202 amino acid residues) isolated from the venom of trimeresurus flavoviridis is a member of a new subfamily of metalloproteinases. we now report the complete amino acid sequence of a high molecular mass hemorrhagic protein isolated from the sam ...	1990	2398046
glycerol monoethers in the scent gland secretions of the western diamondback rattlesnake (crotalus atrox; serpentes, crotalinae).	1-o-monoalkylglycerols with c12 to c20 chains were identified in the scent gland secretions of the western diamondback rattlesnake (crotalus atrox). this is the first documentation of these compounds in the skin secretions of a reptile.	1990	2373208
identification of the cleavage sites by a hemorrhagic metalloproteinase in type iv collagen.	type iv collagen, solubilized from engelbreth-holm-swarm (ehs) tumor basement membranes is digested by a hemorrhagic metalloproteinase, ht-e, isolated from the crude venom of the western diamondback rattlesnake, crotalus atrox. the major proteolytic products have mr 141,000, 132,000, 87,000, 71,000, 33,000 and approximately 18,000 as estimated by sds-gel electrophoresis of pepsinized type iv collagen fragments. sequence analysis of the digestion products reveal that the mr 141,000, 71,000 and ap ...	1990	2374521
hydrolysis of supported pyrenephospholipid monolayers by phospholipase a2.	hydrolysis by pancreatic and snake venom (crotalus atrox) phospholipase a2 of fluorescent monolayers of pyrene-labelled phosphatidylglycerol on solid support was studied. we used a fluorescence microscope equipped with video camera, video recorder and an image analyzer to monitor changes in fluorescence. decrease in pyrene excimer emission was evident when pyrene phosphatidylglycerol monolayers transferred onto quartz glass slides (at a surface pressure of 15 mn m-1) were subjected to enzymatic ...	1990	2208445
investigation of an active site histidine-aspartate couple in trimeresurus flavoviridis phospholipase a2.	when trimeresurus flavoviridis phospholipase a2 was reacted with methyl p-nitrobenzenesulfonate, its activity decreased following first-order kinetics. the ph dependence of the rate constants of inactivation showed that his-48 with an apparent pka of 6.5 controls the reaction. in the ph region below 6.5, n1-methylhistidine was predominantly formed. on the other hand, n1,n3-dimethylhistidine was almost exclusively produced in the ph region above 6.5. no n3-methylhistidine was detected at any ph t ...	1989	2628422
degradation of extracellular matrix proteins by hemorrhagic metalloproteinases.	the proteolytic activity of four hemorrhagic metalloproteinases (ht-a, c, d, and e) isolated from the venom of the western diamondback rattlesnake (crotalus atrox) was investigated using isolated extracellular matrix (ecm) proteins. we determined that all of the proteinases are capable of cleaving fibronectin, laminin, type iv collagen, nidogen (entactin), and gelatins. however, none of the proteinases were proteolytic against the interstitial collagen types i and iii or type v collagen. with al ...	1989	2817904
responses by canids to scent gland secretions of the western diamondback rattlesnake (crotalus atrox).	many snakes discharge malodorous fluids from paired scent glands in the base of the tail when they are disturbed. a number of authors suggest that these secretions repel predators. scent gland secretions of the western diamondback rattlesnake (crotalus atrox), or dichloromethane extracts of them, were presented to coyotes (canis latrans) in three field tests, and to domestic dogs (canis familiaris) in two kennel tests, to determine whether responses of possible benefit to snakes are elicited. fr ...	1989	24272101
comparative enzymatic study of hplc-fractionated crotalus venoms.	1. ten venoms of the genus crotalus (crotalus adamanteus, crotalus atrox, crotalus durissus durissus, crotalus horridus horridus, crotalus lepidus, crotalus polystictus, crotalus molossus molossus, crotalus pusillus, crotalus scutulatus scutulatus, venom b, and crotalus viridis lutosus) were fractionated using hplc anion and cation exchange chromatography. 2. hplc venom fractions were tested for hemorrhagic, hemolytic, and proteolytic activities. 3. crude virginia opossum (didelphis virginiana) ...	1989	2680253
platelet-aggregation is stimulated by lactose-inhibitable snake venom lectins.	five lactose-specific lectins from snake venoms were tested for the ability to stimulate the aggregation of human platelets. three of the lectins, bushmaster (lachesis muta), cottonmouth (ancistrodon piscivorous leukostoma) and rattlesnake (crotalus atrox) lectins, consistently stimulated secretion and aggregation. thrombolectin (bothrops atrox) occasionally caused aggregation. copperhead (agkistrodon contortrix contortrix) lectin did not by itself cause platelet aggregation. lactose, a specific ...	1989	2530646
amino acid sequence of a crotalus atrox venom metalloproteinase which cleaves type iv collagen and gelatin.	the hemorrhagic toxin ht-d from venom of the western diamondback rattlesnake is a metalloproteinase with a molecular weight of 23,234. peptides were obtained from enzymatic and chemical digestions, separated by reverse-phase chromatography, and sequenced in a gas-phase sequenator. the sequence showed a putative zinc binding site similar to that of thermolysin and other metalloproteinases but no overall significant similarity to the sequences of other metalloproteinases and may represent a new su ...	1989	2745407