| expression of a group ii phospholipase a2 from the venom of agkistrodon piscivorus piscivorus in escherichia coli: recovery and renaturation from bacterial inclusion bodies. | a synthetic gene encoding the group ii phospholipase a2 (pla2) from the venom of agkistrodon piscivorus piscivorus has been constructed and expressed with high efficiency in escherichia coli. no enzymatic activity was recovered when the polypeptide contained the initiator met residue. replacement of an asn residue penultimate to the initiator met with ser or gly permitted removal of the initiator met by the endogenous methionine aminopeptidase. the amino-terminal serine (n-ser) and amino-termina ... | 1992 | 1336691 |
| calcium and magnesium dependence of phospholipase a2-catalyzed hydrolysis of phosphatidylcholine small unilamellar vesicles. | the ca2+ requirement for lipid hydrolysis catalyzed by phospholipase a2 from agkistrodon piscivorus piscivorus (app-d49) and porcine pancreas has been examined using small, unilamellar vesicles of dipalmitoylphosphatidylcholine (dppc suv). hydrolysis was affected by product inhibition even at early times, and the extent of this inhibition depended on the concentration of divalent cations. the ca2+ requirement for half-maximal rates of hydrolysis reflected, in part, this non-catalytic role of div ... | 1992 | 1400456 |
| local heat and cold application after eastern cottonmouth moccasin (agkistrodon piscivorus) envenomation in the rat: effect on tissue injury. | we studied the effect of local application of heat or cold on the development of tissue necrosis in envenomated rats. anesthetized animals had 6 mg/kg venom from agkistrodon piscivorus injected subcutaneously into the lateral aspect of a hind limb. heat or cold was applied to the site of envenomation in the experimental groups for 4-6 hr, and the injected area was examined histologically after 24 hr. neither local treatment, with or without the presence of systemic antivenin, significantly affec ... | 1992 | 1485335 |
| reversibility of the activation of soluble phospholipase a2 on lipid bilayers: implications for the activation mechanism. | the time-courses of hydrolysis of large vesicles of dipalmitoylphosphatidylcholine were compared using four species of phospholipase a2 (agkistrodon piscivorus piscivorus, crotalus adamanteus and naja naja venoms and porcine pancreatic). in all four cases, the hydrolysis rate suddenly increases 10 to 100-fold at the time (tau) when a specific mole fraction of reaction products has accumulated. the intrinsic fluorescence emission of the three venom enzymes also increases suddenly at time tau. bot ... | 1992 | 1643108 |
| myotoxin ii from bothrops asper (terciopelo) venom is a lysine-49 phospholipase a2. | a basic, dimeric myotoxic protein, myotoxin ii, purified from bothrops asper venom has a similar molecular weight and is immunologically cross-reactive with antibodies raised to previously isolated b. asper phospholipases a2, except that it shows only 0.1% of the phospholipase activity against l-alpha-phosphatidylcholine in the presence of triton x-100. its 121 amino acid sequence, determined by automated edman degradation, clearly identifies it as a lys-49 phospholipase a2. key amino acid diffe ... | 1991 | 1899180 |
| 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 |
| binding of the snake venom-derived proteins applaggin and echistatin to the arginine-glycine-aspartic acid recognition site(s) on platelet glycoprotein iib.iiia complex inhibits receptor function. | in the present report we describe the platelet-binding characteristics of applaggin and echistatin, potent inhibitors of fibrinogen-dependent platelet aggregation derived from agkistrodon piscivorus piscivorus and echis carinatus snake venoms, respectively. both molecules bound to unstimulated platelets in a specific and saturable manner. at saturation there were 37,100 +/- 3,150 (mean, +/- s.d.) molecules of applaggin and 27,200 +/- 2,816 molecules of echistatin bound/platelet, with dissociatio ... | 1990 | 2365698 |
| the role of asp-49 and other conserved amino acids in phospholipases a2 and their importance for enzymatic activity. | the role of aspartic acid-49 (asp-49) in the active site of porcine pancreatic phospholipase a2 was studied by recombinant dna techniques: two mutant proteins were constructed containing either glutamic acid (glu) or lysine (lys) at position 49. enzymatic characterization indicated that the presence of asp-49 is essential for effective hydrolysis of phospholipids. conversion of asp-49 to either glu or lys strongly reduces the binding of ca2+ ions, in particular for the lysine mutant, but the aff ... | 1989 | 2722967 |
| the role of aspartic acid-49 in the active site of phospholipase a2. a site-specific mutagenesis study of porcine pancreatic phospholipase a2 and the rationale of the enzymatic activity of [lysine49]phospholipase a2 from agkistrodon piscivorus piscivorus' venom. | in order to probe the role of asp-49 in the active site of porcine pancreatic phospholipase a2 two mutant proteins were constructed containing either glu or lys at position 49. their enzymatic activities and their affinities for substrate and for ca2+ ions were examined in comparison with the native enzyme. enzymatic characterization indicated that the presence of asp-49 is essential for effective hydrolysis of phospholipids. conversion of asp-49 to either glu or lys strongly reduces the binding ... | 1988 | 3046944 |
| the lysine-49 phospholipase a2 from the venom of agkistrodon piscivorus piscivorus. relation of structure and function to other phospholipases a2. | a new class of phospholipases a2 that have a lysine at position 49 differ from the more conventional asp-49 enzymes with respect to the sequential binding of the essential cofactor, calcium, and the substrate, phospholipid, in the formation of the catalytic complex (maraganore, j.m., merutka, g., cho, w., welches, w., kézdy, f.j., and heinrikson, r.l. (1984) j. biol. chem. 259, 13839-13843). we report here the complete amino acid sequence of the lys-49 enzyme from agkistrodon piscivorus piscivor ... | 1986 | 3082870 |
| comparison of enzymatic and pharmacological activities of lysine-49 and aspartate-49 phospholipases a2 from agkistrodon piscivorus piscivorus snake venom. | the basic lys-49 phospholipase a2 (pla2) from agkistrodon piscivorus piscivorus venom is homologous to the basic asp-49 pla2 from the same venom as well as other snake venom pla2 enzymes. it differs, however, in several respects, most important being replacement of the previously invariant asp-49 at the calcium binding site by lys, resulting in a reversed order of addition of calcium and phospholipid, phospholipid binding first. although the preferences for phospholipid substrates of the two enz ... | 1987 | 3109429 |
| the chemical basis for interfacial activation of monomeric phospholipases a2. autocatalytic derivatization of the enzyme by acyl transfer from substrate. | a basic monomeric phospholipase a2 from the venom of the american water moccasin, agkistrodon piscivorus piscivorus, undergoes ca2+-dependent, autocatalytic acylation during the course of hydrolysis of both model and natural phospholipid substrates. acylation occurs at 2 lysine residues, lys-7 and lys-10, in the nh2-terminal alpha-helical segment of the enzyme, and when both positions are fully derivatized, the stable bisacylphospholipase a2 becomes a dimer in solution. the acylated enzyme is fu ... | 1988 | 3403524 |
| subnuclear organization of the ophidian trigeminal motor nucleus. ii. ultrastructural measurements on motoneurons innervating antagonistic muscles. | horseradish peroxidase (hrp), injected intramuscularly, specifically labeled motoneurons innervating antagonistic jaw muscles in the cottonmouth mocassin, agkistrodon piscivorus piscivorus. adductor mandibulae profundus, part 3a, motoneurons were localized in the lateral regions of the ventral and intermediate subnuclei of the trigeminal (v) motor nucleus. these were large cells containing fine, granular reaction product characteristic of alpha-motoneurons. small cells, which contained large coa ... | 1980 | 7391269 |
| 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 |
| structure and effects of a kinin potentiating fraction f (appf) isolated from agkistrodon piscivorus piscivorus venom. | the contractile action of bradykinin on isolated smooth muscles is known to be potentiated by special peptides isolated from snake venoms and other animal sources. a fraction f (appf) has been derived from agkistrodon piscivorus piscivorus venom. this fraction does not increase the depressor effect of bradykinin n blood pressure, potentiates the action of bradykinin on isolated guinea-pig ileum and prolongs the duration of relaxation in isolated rat duodenum. this fraction was able to inhibit th ... | 1995 | 8599182 |
| 1h, 15n and 13c resonance assignments and secondary structure of group ii phospholipase a2 from agkistrodon piscivorus piscivorus: presence of an amino-terminal helix in solution. | 1h, 15n and 13c resonance assignments are presented for the group ii phospholipase a2 (pla2) from agkistrodon piscivorus piscivorus. the secondary structure of the enzyme has been inferred from an analysis of coupling constants, interproton distances, chemical shifts, and kinetics of amide exchange. overall, the secondary structure of this pla2 is similar to the crystal structure of the homologous group ii human nonpancreatic secretory phospholipase [scott, d.l., white, s.p., browning, j.l., ros ... | 1996 | 8616268 |
| structural aspects of interfacial adsorption. a crystallographic and site-directed mutagenesis study of the phospholipase a2 from the venom of agkistrodon piscivorus piscivorus. | recent genetic and structural studies have shed considerable light on the mechanism by which secretory phospholipases a2 interact with substrate aggregates. electrostatic forces play an essential role in optimizing interfacial catalysis. efficient and productive adsorption of the class i bovine pancreatic phospholipase a2 to anionic interfaces is dependent upon the presence of two nonconserved lysine residues at sequence positions 56 and 116, implying that critical components of the adsorption s ... | 1997 | 9013608 |
| primary structure and biological activity of snake venom lectin (apl) from agkistrodon p. piscivorus (eastern cottonmouth). | a lectin (apl) was purified from the venom of agkistrodon piscivorus piscivorus (eastern cottonmouth moccasin). apl is a disulfide-linked, homodimeric protein consisting of identical monomers of molecular weight 16,200. native rabbit and human erythrocytes were agglutinated by apl and the activity was found to be calcium-dependent. galactose, lactose, rhamnose and egta strongly inhibited the hemagglutination activity of apl. the complete amino acid sequence determined by edman sequencing of the ... | 1999 | 10484740 |
| differential roles of ionic, aliphatic, and aromatic residues in membrane-protein interactions: a surface plasmon resonance study on phospholipases a2. | the roles of cationic, aliphatic, and aromatic residues in the membrane association and dissociation of five phospholipases a(2) (pla(2)), including asp-49 pla(2) from the venom of agkistrodon piscivorus piscivorus, acidic pla(2) from the venom of naja naja atra, human group iia and v pla(2)s, and the c2 domain of cytosolic pla(2), were determined by surface plasmon resonance analysis. cationic interfacial binding residues of a. p. piscivorus pla(2) (lys-10) and human group iia pla(2) (arg-7, ly ... | 2001 | 11294634 |
| identification of the myotoxic site of the lys49 phospholipase a(2) from agkistrodon piscivorus piscivorus snake venom: synthetic c-terminal peptides from lys49, but not from asp49 myotoxins, exert membrane-damaging activities. | group ii phospholipase a(2) (pla(2)) myotoxins found in the venoms of crotalidae snakes can be divided into 'asp49' and 'lys49' isoforms, the latter being considered catalytically-inactive variants. previous studies on one lys49 isoform, myotoxin ii from bothrops asper, indicated that its myotoxic activity is due to the presence of a short cationic/hydrophobic sequence (115-129) near its c-terminus, which displays membrane-damaging properties. since the c-terminal region of different group ii pl ... | 2001 | 11478967 |
| the crystal structure of a lysine 49 phospholipase a2 from the venom of the cottonmouth snake at 2.0-a resolution. | the crystal structure of a lysine 49 variant phospholipase a2 (k49 pla2) has been determined at 2.0-a resolution. this particular phospholipase a2, purified from the venom of the eastern cottonmouth (agkistrodon piscivorus piscivorus), a north american pit viper, differs significantly from others studied crystallographically because of replacement of the aspartate residue at position 49, whose side chain is important in calcium binding, by lysine. the crystallographic analysis of k49 pla2 was un ... | 1994 | 2120215 |
| purification and characterization of a new rgd/kgd-containing dimeric disintegrin, piscivostatin, from the venom of agkistrodon piscivorus piscivorus: the unique effect of piscivostatin on platelet aggregation. | piscivostatin, a novel dimeric disintegrin containing arg-gly-asp (rgd) and lys-gly-asp (kgd) sequences, was isolated from the venom of agkistrodon piscivorus piscivorus. the molecule consisted of two chains designated as the alpha and beta chains, comprising 65 and 68 amino acid residues, respectively. piscivostatin had two binding motifs recognized by platelet glycoprotein iib/iiia (gpiib/iiia), and the biological activity of dimeric disintegrin piscivostatin toward platelet aggregation differ ... | 2001 | 11530017 |
| changes in ca2+ affinity upon activation of agkistrodon piscivorus piscivorus phospholipase a2. | changes in the affinity of calcium for phospholipase a2 from agkistrodon piscivorus piscivorus during activation of the enzyme on the surface of phosphatidylcholine vesicles have been investigated by site-directed mutagenesis and fluorescence spectroscopy. changes in fluorescence that occur during lipid binding and subsequent activation have been ascribed to each of the three individual trp residues in the protein. this was accomplished by generating a panel of mutant proteins, each of which lac ... | 2001 | 11258945 |
| crystallization and preliminary diffraction data of a platelet-aggregation inhibitor from the venom of agkistrodon piscivorus piscivorus (north american water moccasin). | applaggin (agkistrodon piscivorus piscivorus platelet-aggregation inhibitor) is a potent inhibitor of blood platelet aggregation derived from the venom of the north american water moccasin. the protein consists of 71 amino acids, is rich in cysteines, contains the sequence-recognition site of adhesion proteins at positions 50-52 (arg-gly-asp) and shares high sequence homology with other snake-venom disintegrins such as echistatin, kistrin and trigramin. single crystals of applaggin have been gro ... | 1999 | 10417418 |
| crystal structure of piratoxin-i: a calcium-independent, myotoxic phospholipase a2-homologue from bothrops pirajai venom. | the crystal structure of piratoxin-i (prtx-i) a lys49 homologue isolated from the venom of bothrops pirajai has been determined and refined at 2.8 a to a crystallographic residual of 19.7% (rfree = 29.7%). amino-acid sequence differences between catalytically active phospholipases and prtx-i in the putative ca2+-binding loop, specifically the substitutions tyr28 --> asn, gly32 --> leu and asp49 --> lys, result in an altered conformation of this loop. the analysis of the position of the epsilon-a ... | 1998 | 9723838 |
| lys-49-phospholipases a2 as active enzyme for beta-arachidonoyl phospholipid bilayer membranes. | phospholipases a2 containing lys-49 have been reported to be extremely weak or inactive as enzyme. we have recently shown that basic proteins i and ii (bp-i and bp-ii), lys-49-pla2s isolated from the venom of trimeresurus flavoviridis (habu snake), are potent to hydrolyze the arachidonate of 2-arachidonoyl-1-stearoyl-l-3-phosphatidylcholine (aspc) in bilayer vesicles. in order to ensure such enzymatic activity of lys-49-pla2s, two other lys-49-pla2s from different snake venoms, myotoxin ii (from ... | 1997 | 9315278 |
| effects of temperature and glycerides on the enhancement of agkistrodon piscivorus piscivorus phospholipase a2 activity by lysolecithin and palmitic acid. | the effect of temperature and various glycerides to modulate the ability of lysolecithin and fatty acid to promote high phospholipase a2 activity was studied using dipalmitoylphosphatidylcholine large unilamellar vesicles as substrate. the length of the lag phase prior to the accumulation of sufficient hydrolysis products (lysolecithin and fatty acid) to support high phospholipase activity was shortest at temperatures near the thermotropic phase transition of the phospholipid substrate. a reduct ... | 1995 | 7547886 |
| purification and characterization of piscivorase i and ii, the fibrinolytic enzymes from eastern cottonmouth moccasin venom (agkistrodon piscivorus piscivorus). | fibrinolytic enzymes, piscivorase i and ii, were isolated from agkistrodon piscivorus piscivorus (eastern cottonmouth moccasin) venom using gel filtration on bio-gel p-100 and ion-exchange chromatography on cm-sepharose cl-6b. the mol. wts of these proteases, piscivorase i and ii, are 23,400 and 29,000 and isoelectric points are 6.6 and 8.5, respectively. these fibrinolytic enzymes were homogeneous by sds-polyacrylamide gel electrophoresis. piscivorase i readily cleaved the a alpha- and b beta-c ... | 1995 | 8588217 |
| enhancement of agkistrodon piscivorus piscivorus venom phospholipase a2 activity toward phosphatidylcholine vesicles by lysolecithin and palmitic acid: studies with fluorescent probes of membrane structure. | the activity of phospholipase a2 from snake venom to hydrolyze bilayers of phosphatidylcholines is greatly enhanced by the presence of the hydrolysis products, lysolecithin and fatty acid, in the bilayer. the fluorescence of several probes of membrane structure was used to monitor changes in bilayer physical properties during vesicle hydrolysis. these changes were compared to emission spectra and fluorescence polarization results occurring upon direct addition of lysolecithin and/or fatty acid t ... | 1995 | 7794890 |
| autocatalytic acylation of phospholipase-like myotoxins. | several snake venoms contain a phospholipase a2 in which position 49 in the active site is occupied by a lysine or a serine instead of the aspartate residue normally found. although these proteins do not bind ca2+ and are devoid of catalytic activity, they are still highly specific myotoxins and have recently been shown to induce membrane leakage by a new type of cytolytic mechanism. three of these toxins, myotoxin ii from bothrops asper, ammodytin l from vipera ammodytes, and the k49 protein fr ... | 1995 | 7718570 |
| effects of specific fatty acid acylation of phospholipase a2 on its interfacial binding and catalysis. | monomeric phospholipase a2 (pla2) from the venom of agkistrodon piscivorus piscivorus (app-d49) was treated with 3-acyloxy-4-nitrobenzoic acids to acylate the epsilon-amino groups of two lysines (lys-7 and lys-10) in the amino terminal region. resulting 7,10-diacylated-app-d49s, with acyl groups ranging from lauroyl to palmitoyl, spontaneously aggregated in solution. by contrast, 7,10-dioctanoyl-app-d49 existed as a monomer under the same condition. kinetic and interfacial binding properties of ... | 1994 | 7918373 |
| presence of heat-stable hemorrhagic toxins in snake venoms. | twenty-eight snake venoms (seven agkistrodon venoms, six bothrops venoms, 13 crotalus venoms, one sistrurus venom, and one bitis venom) were examined for the presence of heat-stable (100 degrees c, 5 min) hemorrhagic toxins. both heated and unheated venoms were analyzed for their protein composition by sds-page, and tested for their hemorrhagic activity in vivo in mice and for their proteolytic activity on two different substrates. heating all venoms led to the denaturation and loss of some prot ... | 1994 | 7985199 |
| quantification of the interaction between lysolecithin and phospholipase a2. | the rate of hydrolysis of phosphatidylcholine bilayers by phospholipase a2 may be either enhanced or inhibited by the presence of lysolecithin depending on the experimental conditions examined. to further understand the relationship of lysolecithin to phospholipase a2 activity, the binding of lysolecithin to phospholipase a2 from the venom of agkistrodon piscivorus piscivorus was examined by fluorescence spectroscopy. the tryptophan emission intensity of the enzyme was enhanced by 70% upon addit ... | 1994 | 8130262 |
| 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 |
| the lysine-49 phospholipase a2 from the venom of agkistrodon piscivorus piscivorus. relation of structure and function to other phospholipases a2. | | 1993 | 8449964 |
| molecular details of the activation of soluble phospholipase a2 on lipid bilayers. comparison of computer simulations with experimental results. | the initial rate of hydrolysis of large unilamellar vesicles of dipalmitoylphosphatidylcholine by phospholipase a2 from the venom of agkistrodon piscivorus piscivorus is small and elevates gradually until it suddenly increases by a factor of 10 to 1000 depending on the experimental conditions. this abrupt onset of high enzyme activity appears to be correlated to a specific mole fraction of reaction product at which point a cooperative compositional phase transition in the bilayer occurs. five mo ... | 1992 | 1597446 |
| 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 |
| 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 |
| agkistrodon piscivorus piscivorus platelet aggregation inhibitor: a potent inhibitor of platelet activation. | applaggin (agkistrodon piscivorus piscivorus platelet aggregation inhibitor) is a potent inhibitor of platelet activation. the protein is isolated from the venom of the north american water moccasin snake in three steps, including gel filtration, cation exchange, and reverse-phase hplc procedures. the purified protein migrates as a 17,700-da polypeptide by sds/page under nonreducing conditions and as a 9800-da peptide in the presence of thiol. the behavior of applaggin on sds/page would indicate ... | 1989 | 2510158 |
| the temporal sequence of events in the activation of phospholipase a2 by lipid vesicles. studies with the monomeric enzyme from agkistrodon piscivorus piscivorus. | the substrate dependence of the time courses of hydrolysis of both small and large unilamellar vesicles of dipalmitoylphosphatidylcholine (dppc) by agkistrodon piscivorus piscivorus monomeric phospholipase a2 is consistent with an activation process involving enzyme aggregation on the vesicle surface. the time course of hydrolysis of large unilamellar vesicles is particularly complex; a slow initial rate of hydrolysis is followed by an extremely abrupt increase in enzyme activity. the length of ... | 1989 | 2745435 |
| thermodynamic and kinetic studies of the interaction of vesicular dipalmitoylphosphatidylcholine with agkistrodon piscivorus piscivorus phospholipase a2. | the tryptophan fluorescence emission intensity at 340 nm of monomeric phospholipase a2 from agkistrodon piscivorus piscivorus increased about 70% upon addition of dipalmitoylphosphatidylcholine small unilamellar vesicles (dppc suv) at 25 degrees c. the emission spectrum was also blue-shifted 6-8 nm, suggesting that the environment of 1 or more tryptophan residues had become less polar. this effect of suv on the phospholipase a2 fluorescence was independent of ca2+ at 25 degrees c, and the appare ... | 1989 | 2909516 |
| comparison of enzymatic and pharmacological activities of lysine-49 and aspartate-49 phospholipases a2 from agkistrodon piscivorus piscivorus snake venom. a reconsideration. | | 1989 | 2506677 |
| crystallization and preliminary diffraction studies of the lys-49 phospholipase a2 from agkistrodon piscivorus piscivorus. | previous chemical and structural studies have proposed a major role for asp-49 in the calcium-mediated activation of phospholipases a2. recently, a new class of phospholipases a2 has been characterized with a lysine in the place of aspartate at position 49 (maraganore, j. m., merutka, g., cho, w., welches, w., kézdy, f. j., and heinrikson, r. l. (1984) j. biol. chem. 259, 13839-13843; maraganore, j. m., and heinrikson, r. l. (1986) j. biol. chem. 261, 4797-4804). although both the lys-49 and asp ... | 1986 | 3091601 |
| fine structure and organization of the infrared receptor relay, the lateral descending nucleus of the trigeminal nerve in pit vipers. | the morphology of the nucleus of the lateral descending tract of v has been studied in species of two genera of pit vipers, cottonmouth moccasin (agkistrodon piscivorus piscivorus), and rattlesnake (crotalus ruber and crotalus horridus horridus). the nucleus is the site of termination of primary afferent neurons forming the infrared receptors in the facial pits. it is located on the external surface of the common descending tract of v and contains somata that range in size from 7 to 22 micromete ... | 1981 | 7204672 |
| polysaccharide content of the poison apparatus of the cottonmouth moccasin agkistrodon piscivorus piscivorus. | | 1967 | 4229870 |
| thrombin-like and fibrinolytic enzymes in the venoms from the gaboon viper (bitis gabonica), eastern cottonmouth moccasin (agkistrodon p. piscivorus) and southern copperhead (agkistrodon c. contortrix) snakes. | crude venom from b. gabonica contained weak fibrinogen clotting activity but no visible fibrinolytic activity, whereas venoms from a. p. piscivorus and a. c. contortrix exhibited fibrinolytic activity (by fibrin plate assay) but no thrombin-like activity. these snake venoms were fractionated on sephadex g-100 with the following results. thrombin-like activity in b. gabonica venom was eluted in a single protein peak with a molecular weight of 40,000. agkistrodon p. piscivorus venom contained a si ... | 1982 | 7043785 |
| fractionation and partial characterization of toxic components of agkistrodon p. piscivorus (eastern cottonmouth moccasin) venom. | | 1981 | 7336449 |