Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
|---|
| proteolytic-independent cobra neurotoxin inhibiting activity of curcuma sp. (zingiberaceae). | the 1: 1 (w/v) aqueous extract of curcuma sp. (zingiberaceae) was shown to antagonize the toxic action of naja naja siamensis neurotoxin possibly via direct inactivation of the toxin. the plant extract possessed proteolytic activity which could be separated from the neurotoxin inhibiting activity. the mechanism of antagonism between the plant extract and the neurotoxin was shown not to be involved with the existence of proteolytic activity in the plant extract. | 1983 | 6356379 |
| hypotensive actions of snake parathyroid glands. | parathyroid gland extracts from four different snake species, ptyas korros, ptyas mucosa, elaphe radiata, and naja naja, were prepared and their hypotensive actions were assayed in anesthetized p. korros. all extracts were hypotensive and the responses, except that of n. naja, were dose related. their potencies were, however, different in different species. these data suggest that the hypotensive property of the parathyroid hormone is probably widely distributed in submammalian vertebrates. | 1983 | 6667839 |
| phospholipid asymmetry in the membranes of intact human erythrocytes and in spectrin-free microvesicles derived from them. | phospholipase a2 from bee venom and naja naja has been used to study the orientation of phospholipids present in the membrane of intact human erythrocytes and in spectrin-free microvesicles derived from the cells by treatment with ca2+ and a23187. little difference between the cells and microvesicles was observed in the apparent accessibility of phospholipids to the enzyme, suggesting that the original lipid asymmetry was maintained in the absence of spectrin. however, incubation of the microves ... | 1984 | 6722143 |
| [a case of bite by naja naja naja in india. problems posed by the treatment of snake bites]. | the author reports a case of poisonous snake bite by naja naja naja, in india. the patient recovered rapidly after treatment by antivenom serum. he emphasizes the importance of prompt intravenous injection of serum. serum is less active for viper bites, and should be injected even more rapidly. however, in france, some authors prefer heparin for treating french viper bites. further studies are needed to clarify this therapeutic problem. | 1984 | 6722971 |
| effects of chicken and mammalian gonadotropin-releasing hormones (gnrh) on in vivo pituitary gonadotropin release in amphibians and reptiles. | the ability of mammalian and chicken gonadotropin-releasing hormones (gnrh) and their agonistic analogs to stimulate in vivo gonadotropin release were tested in a frog (rana catesbeiana), snake (naja naja), and turtle (sternotherus odoratus). in the frog, chicken and mammalian gnrh were equipotent in stimulating the release of fsh and lh. attendant increases in plasma androgen and the occurrence of spermiation confirmed the release of biologically active gonadotropin. neither of the gnrh prepara ... | 1984 | 6427062 |
| effect of the purified phospholipases a2 from snake and bee venoms on rabbit platelet function. | effects of seven purified phospholipases a2 from the venoms of snakes (naja naja atra, trimeresurus mucrosquamatus and t. gramineus) and honey bee (apis mellifera) on rabbit washed platelet suspension in the absence of bovine serum albumin have been studied. only phospholipases a2 from n. n. atra, t. mucrosquamatus and a. mellifera venoms induced platelet aggregation with small amounts of 14c-serotonin release. they showed tachyphylaxis and also cross-tachyphylaxis in inducing platelet aggregati ... | 1984 | 6441310 |
| cardiotoxin from naja naja atra snake venom: a potentiator of platelet aggregation. | cardiotoxin, isolated from naja naja atra snake venom, potentiates platelet aggregation induced by adp, thrombin, collagen and venom phospholipase a2. the malondialdehyde formation caused by adp, thrombin and venom phospholipase a2 were also increased in the presence of cardiotoxin. both potentiation of aggregation and increase in malondialdehyde were blocked by indomethacin or ca2+ (5 mm or 0.05 mm). cardiotoxin did not potentiate thrombin-induced aggregation of p-bromophenacyl bromide-modified ... | 1984 | 6474495 |
| catabolism of phospholipids by chicken seminal components after storage. | the possibility of an activation of chicken spermatozoal phospholipase a2 during in vitro storage of undiluted semen was investigated. after storage for periods up to 24 hr at 5 c, the ability of semen to catabolize added phosphatidylcholine labeled on the 2nd carbon of glycerol with 14c oleic acid was assessed. neither spermatozoa nor plasma from undiluted chicken semen was found to be capable of catabolizing added 14c labeled phosphatidylcholine, regardless of the storage period. no enzyme act ... | 1984 | 6483728 |
| joint action of membrane-active components from central asian cobra (naja naja oxiana eichwald) venom on rat liver mitochondrial functions. | 1984 | 6490077 | |
| clinical features of neurotoxic snake bite and response to antivenom in 47 children. | among 47 children admitted to the chulalongkorn medical school hospital for neurotoxic snake bite, the attackers were identified in 15; the cobra (naja naja) was the snake involved in all cases. clinical manifestations in all 47 children appeared to follow a similar pattern. drowsiness heralded the systemic effects in most of the patients. the characteristic systemic signs were those resulting from the neuromuscular effects of the venom and included ptosis, frothy saliva, slurred speech, respira ... | 1984 | 6507733 |
| evidence for a highly asymmetric arrangement of ether- and diacyl-phospholipid subclasses in the plasma membrane of krebs ii ascites cells. | (1) krebs ii ascites cells were taken as a model of the neoplastic cells to investigate the transverse distribution of phospholipids in the plasma membrane. the experimental procedure was based on non-lytic degradation of phospholipids in the intact cell by naja naja phospholipase a2 and staphylococcus aureus sphingomyelinase c and on phospholipid analysis of purified plasma membranes. it was shown that the three major phospholipids, i.e., phosphatidylcholine, phosphatidylethanolamine and sphing ... | 1984 | 6509047 |
| effect of carboxylate group modification on enzymatic and cardiotoxic properties of snake venom phospholipases a2. | by treating naja nigricollis and naja naja atra phospholipase a2 with carbodiimide and semicarbazide, we obtained derivatives having varied numbers of modified carboxylate groups. when tested on artificial and natural substrates, derivatives of both enzymes with a modified carboxylate group at the active site (asp-49) retained little enzymatic activity (1/41 to 10%). however, the derivatives of n. nigricollis also lost most of their lethal potency (5% of native), while those of n. n. atra retain ... | 1984 | 6523504 |
| effect of ca2+ on the action of cobra (naja naja oxiana eichwald) venom components on mitochondrial enzyme systems. | 1984 | 6526419 | |
| [a new low molecular-weight protein effector of human complement from the venom of the central asian cobra naja naja oxiana]. | six protein effectors of human complement were isolated from the whole venom of the central asian cobra naja naja oxiana. three of them have acidic properties and molecular weights of 61 000, 5000 and 3000, and the rest are basic proteins with molecular weights of 54 000, 9000 and 7000. two low molecular weight basic proteins cfb-ii and cfb-iii are isolated in as high amounts as 115 and 85 mg per g of dry venom. all the effectors inhibit the classical pathway of complement activation and, with t ... | 1984 | 6567467 |
| stimulation of prostaglandin e2 synthesis by exogenous phospholipase a2 and c in rabbit kidney medulla slices. | we have investigated the effects of phospholipase a2 and c on the synthesis of prostaglandin e2 in rabbit kidney medulla and the release of fatty acids from the medulla slices. exogenous phospholipase a2 [from naja naja (indian cobra) venom] and phospholipase c (from clostridium welchii) stimulated prostaglandin e2 production in a dose-dependent manner. at the maximal effective concentrations (0.5 unit of phospholipase a2/ml, 2 units of phospholipase c/ml), phospholipase c increased prostaglandi ... | 1984 | 6585201 |
| complement in the serum and venom of brazilian snakes (crotalidae). | proteins antigenically related to cof, the anticomplementary protein of the venom of the indian hooded cobra (naja naja), were found in a variety of elapid and viper venoms but not in the venom of brazilian crotalids . in keeping with this finding was the weak ability of brazilian snake venom to convert c3 in human serum. all snake serums tested, including brazilian crotalids , contained a beta-globulin antigenically related to cof. this serum protein in brazilian snake serum had a number of cha ... | 1984 | 6587747 |
| proteolytic activities of cobra venoms based on inactivation of alpha 2-macroglobulin. | the venoms of various cobra species showed a wide range of abilities to cleave hide powder azure, with naja naja kaouthia and ophiophagus hannah venoms showing the lowest activities and naja nivea venom showing the greatest activity on this dye-linked substrate. the activities of the venoms on hide powder did not completely correlate with their ability to inactivate the alpha 2-macroglobulin of human serum. incubation of 4-5 micrograms of naja nigricollis venom per microliter of serum for 30 min ... | 1984 | 6197999 |
| higher-order structure in the 3'-terminal domain vi of the 23 s ribosomal rnas from escherichia coli and bacillus stearothermophilus. | an experimental approach was used to determine, and compare, the higher-order structure within domain vi of the 23 s ribosomal rnas from escherichia coli and bacillus stearothermophilus. this domain, which encompasses approximately 300 nucleotides at the 3' end of the rnas, consists of two large subdomains. the 5' subdomain has been conserved during evolution and appears to be functionally important for the binding of the ef-1 x gtp x aminoacyl-trna complex in eukaryotes. the 3' subdomain has di ... | 1984 | 6209406 |
| anaerobic metabolism of carbon tetrachloride and formation of catabolically resistant phospholipids. | anaerobic incubation of microsomes with 14c-carbon tetrachloride leads to trichloromethyl radicals which, apart from other detrimental reactions, bind covalently to phospholipids. these labelled lipids are extracted, phosphatidylcholine is isolated and incubated with phospholipase a2 from naja naja snake venom and from porcine pancreas. half of the covalently modified phosphatidylcholine is resistant toward phospholipase a2. distribution of such catabolically resistant phospholipids from the end ... | 1984 | 6231931 |
| properties of curaremimetic neurotoxin binding sites in the rat central nervous system. | properties of mammalian central nervous system binding sites for curaremimetic neurotoxins are investigated with the simonsen-albino rat and 125i-labeled alpha-bungarotoxin or the principal neurotoxin from naja naja siamensis. evidence is presented that high-affinity toxin binding sites are distributed as expected for a synaptic neurotransmitter receptor, display distinct nicotinic cholinergic pharmacology, and are sensitive to preincubation with nicotinic agonists. affinity of toxin sites for a ... | 1984 | 6231955 |
| variation in yield and lethality of venoms from iranian snakes. | the dangerous venomous terrestrial snakes of iran belong to three groups: the elapidae (cobras); the viperinae (true vipers); the crotalinae (pit vipers). geographical distribution of each species was determined. studies on the venoms extracted from the following iranian snakes, oxus cobra, naja naja oxiana, levantine viper (afyi), vipera lebetina, carpet viper, echis carinatus, persian horned viper, pseudocerastes persicus, latifii viper, vipera latifii, mountain viper, vipera xanthina and cauc ... | 1984 | 6474490 |
| on the interaction of cobra venom protein cardiotoxins with erythrocytes. | the principally active hemolytic toxin (cardiotoxin) previously purified from the venom of the thailand cobra, naja naja siamensis, was shown to produce spontaneous twitching, contractures and membrane depolarization in sartorius muscles from the frog, rana pipiens. spontaneous twitching, observed at concentrations greater than 0.1 um was completely abolished by addition of tetrodotoxin and not affected by d-tubocurarine. dose and time dependent membrane depolarization of muscle fibers was obser ... | 1984 | 6333874 |
| [complement and noncomplement hemolysis of blood cells in patients with various blood diseases after the administration of the crude toxins of agkistrodon piscivorus, naja naja, naja oxiana]. | 1984 | 6515308 | |
| bindings of ca2+ and substrate analogs to a cobra venom phospholipase a2 in which the alpha-amino group is modified to an alpha-keto group. | the ph dependence of the chemical reaction rate of p-bromophenacyl bromide (bpb) with his 48 of cobra (naja naja atra) venom phospholipase a2, in which the alpha-nh2 group had been selectively modified to an alpha-keto group, was studied at 25 degrees c and ionic strength 0.1 in the absence of ca2+. the ph-dependence curve was monophasic with a midpoint at ph 7.9, which corresponds to the pk value of his 48 of the alpha-nh2-modified enzyme, whereas the curve for the intact enzyme was biphasic, i ... | 1984 | 6530402 |
| [fluorescence characteristics of lysine and arginine residues in venom of naja naja atra]. | 1984 | 6239506 | |
| inactivation of toxin b from the indian cobra by cleavage of a specific bond during limited hydrolysis with trypsin. | two neurotoxins, "toxin b", a long neurotoxin from naja naja, and "cobrotoxin", a short neurotoxin from naja naja atra, were compared with respect to their limited hydrolysis by trypsin and chymotrypsin and its effect on their neurotoxicity. limited hydrolysis of toxin b with trypsin cleaves peptide bonds at arg68-lys69 and arg33-gly34 in the toxin molecule and causes complete loss of the neurotoxicity yielding des-carboxyl terminal toxin b(1-68) nicked at arg33-gly34 in the molecule. on the oth ... | 1984 | 6487344 |
| photochemically induced nuclear polarization study of exposed tyrosines, tryptophans, and histidines in postsynaptic neurotoxins and in membranotoxins of elapid and hydrophid snake venoms. | the accessibility of surface tyrosines, histidines, and tryptophans in snake venom neurotoxins (short and long) and in membranotoxins to excited triplet 10-(carboxyethyl)-flavin was studied by photochemically induced dynamic nuclear polarization at 270 mhz. trp-29 is accessible in the short neurotoxins--erabutoxins a, b, and c and cobrotoxin--and also in the long neurotoxins--alpha-cobratoxin and alpha-bungarotoxin. tyr-25 is practically inaccessible in all neurotoxins. tyr-39 in cobrotoxin and ... | 1984 | 6498168 |
| cobra venom factor: improved method for purification and biochemical characterization. | a method to purify cobra venom factor (cvf) from cobra venom by sequential column chromatography is described which yields a product virtually free of phospholipase a2, a common contaminant of cvf preparations. the separation of phospholipase a2 from cvf was achieved by chromatography on cibacron blue-agarose, a resin that tightly binds cobra venom phospholipase a2. a rapid and simple hemolytic assay for the qualitative and quantitative determination of cvf based on its ability to induce bystand ... | 1984 | 6491300 |
| reoxidation and renaturation studies on the main toxin of naja naja samarensis. | the main toxin of naja naja samarensis is a very small and rigid protein (mr 6850, 8 cysteines). when fully reduced, it regains its native conformation by a mechanism involving a rapid cysteine oxidation and a slower, less temperature-dependent disulfide exchange. in a native-like form of the protein we observed a population whose cysteines were incompletely reoxidized. when intermediates with blocked cysteines were incubated with oxidized and reduced glutathione, the percentage of native-like m ... | 1984 | 6500055 |
| [2-d-nmr study of the conformation characteristics of toxin 3 from naja naja siamensis venom]. | the spatial structure of "long" toxin 3 naja naja siamensis in solution has been studied by methods of two-dimensional (2d) 1h nmr spectroscopy. the individual signal assignments for 67 out of 71 residues and analysis of nuclear overhauser effects between distinct protons of the molecule allowed the comparison of the toxin 3 conformations at different ph values and temperatures. it was shown that the deprotonated imidazole ring of his22 residue (at ph greater than or equal to 7,5) is surrounded ... | 1984 | 6529443 |
| amino acid sequence of cytotoxin iia isolated from the venom of the indian cobra (naja naja). | a cytotoxic basic polypeptide, designated as cytotoxin iia, was purified to homogeneous state from the venom of the indian cobra (naja naja) by a combination of gel filtration on sephadex g-50, cm-cellulose chromatography, and fast protein liquid chromatography. cytotoxin iia is a single polypeptide consisting of 60 amino acid residues with four intramolecular disulfide linkages. the toxin showed high cytotoxicity toward yoshida sarcoma and ascites hepatoma cells as did cytotoxins i and ii isola ... | 1984 | 6525197 |
| [nmr study of the spatial structure of the naja naja siamensis toxin 3]. | the 300 and 500 mhz 1h nmr spectra of a long-chain neurotoxin, toxin 3 naja naja siamensis (s-t3), its derivatives and close homolog, toxin 3 naja naja naja (n-t3), have been analyzed. a combination of double resonance, difference spectroscopy and usage of a series of toxin s-t3 derivatives acetylated or trifluoroacetylated at lysine residues allowed to assign the signals from all aromatic protons and a number of signals in the aliphatic region, and to elucidate the microenvironment of certain f ... | 1984 | 6437411 |
| fluorescence energy transfer between cobra alpha-toxin molecules bound to the acetylcholine receptor. | an approach was developed with steady state fluorescence energy transfer measurements to examine the spatial relationship between the two alpha-toxins bound to the acetylcholine receptor. by taking advantage of the slow dissociation rates of alpha-toxins (naja naja siamensis 3) from the receptor and of the equal probability with which alpha-toxins bind to the two alpha-toxin-binding sites, we derived an equation which allows prediction of a "true" efficiency of transfer based on the relationship ... | 1984 | 6715368 |
| effect of central asian cobra (naja naja oxiana eichwald) venom cytotoxin on enzymatic hydrolysis of phospholipids. | 1984 | 6490078 | |
| [relative localization of the bound acetylcholine receptor subunits and neurotoxin]. | a series of neurotoxin ii (naja naja oxiana) derivatives, each containing one p-azido-[14c]benzoyl group, have been prepared. those labeled at leu1, lys15, lys25, lys26, or lys46 associate specifically with the acetylcholine receptor from the torpedo marmorata electric organs and form the crosslinks with it as a result of irradiation. electrophoresis in polyacrylamide gel and gel chromatography revealed the contacts between the neurotoxins and alpha, beta, gamma and delta subunits of the recepto ... | 1984 | 6487390 |
| a comparison of eel electroplax and snake venom acetylcholinesterase. | the effects of some cholinergic ligands, harmala alkaloids and local anesthetics on the activity of eel electroplax and naja naja siamensis venom acetylcholinesterase have been studied. in most cases, eel electroplax was found to be more susceptible towards inhibition than the venom acetylcholinesterase. no major difference was observed with respect to the type of inhibition in both enzymes. the activation of the two enzyme preparations by inorganic cations (ca2+, mg2+ and na+) showed a similar ... | 1984 | 6146473 |
| effect of alkylation of tryptophan residues on the enzymatic and pharmacological properties of snake venom phospholipase a2. | snake venom phospholipases a2 show a remarkable degree of amino acid sequence homology yet differ markedly in enzymatic and pharmacological activities. the basic phospholipase a2 from naja nigricollis venom has much greater lethal potency, cardiotoxicity, hemolytic and anticoagulant activity than the acidic or neutral enzymes from naja naja atra or hemachatus haemachatus venoms, respectively, even though it has lower enzymatic activity than the latter two enzymes. previous studies in which we se ... | 1985 | 3924381 |
| [the detoxification of naja naja atra venom and preparation of potent antivenin]. | the 99.2% toxicity of naja naja atra venom can be detoxified by treatment with 0.25% ga (glutaraldehyde) solution at ph 6.8 and still remains its antigenicity. using the ga treated venom incorporated with freund's complete adjuvant as immunogen, the titer of immune horse sera can be enhanced rapidly. the modified immunization method not only shortened the period of immunization (from 180 to 60 days), but also increased the potency of immune sera (from 75 to 170 units). the method also diminished ... | 1985 | 3933920 |
| aggregation studies on fluorescein-coupled cobra venom phospholipase a2. | phospholipase a2 from naja naja naja venom (indian cobra) undergoes a concentration-dependent aggregation, and at an assay concentration of 1 microgram ml-1, it exists as a monomer. however, there is some evidence that the enzyme is actually active as a dimer or higher order aggregate. previous attempts to determine the aggregation state of the enzyme under actual assay conditions were thwarted by experimental difficulties due in part to the low enzyme concentrations required. this aggregation h ... | 1985 | 3936540 |
| methyl branching in short-chain lecithins: are both chains important for effective phospholipase a2 activity? | several seven-carbon fatty acyl lecithins with varied acyl chain branching have been synthesized and characterized as potential phospholipase a2 substrates. micellar bis(4,4-dimethylpentanoyl) phosphatidylcholine, bis(5-methylhexanoyl)phosphatidylcholine, bis(3-methylhexanoyl)phosphatidylcholine, and bis(2-methylhexanoyl)phosphatidylcholine are poor substrates for phospholipase a2 (naja naja naja). these branched lecithins also inhibit the hydrolysis of diheptanoylphosphatidylcholine by the enzy ... | 1985 | 3986178 |
| [biospecific adsorption chromatography of phospholipase a2 from different sources]. | methods of biospecific adsorption chromatography of phospholipase a2 obtained from porcine pancreas and naja naja oxiana, vipera ursini renardi, vespa orientalis venoms were developed. granulated polyamide with covalently linked phosphatidylethanolamine were used as an affinity adsorbent. chemical inertness of linked phosphatidylethanolamine to the hydrolytic action of phospholipase a2 and its high affinity for biospecific complexes are shown. forms of phospholipase a2 different in their affinit ... | 1985 | 3991479 |
| cytolytic activity of cytotoxin isolated from indian cobra venom against experimental tumor cells. | cytolytic activity of cytotoxin isolated from the venom of the indian cobra (naja naja) on experimental tumor cells was far stronger than that on normal cells such as peritoneal exudate cells, spleen cells, and erythrocytes of the rat. the effect on yoshida sarcoma cells was temperature-dependent, being stronger at 37 degrees c than at 0 degrees c. intramolecular disulfide linkages and free amino groups in the cytotoxin molecule were shown to be essential for the lytic action on the cell membran ... | 1985 | 4015662 |
| activation, aggregation, and product inhibition of cobra venom phospholipase a2 and comparison with other phospholipases. | the kinetics of phospholipid hydrolysis by cobra venom phospholipase a2 were examined and compared to those of phospholipase a2 from porcine pancreas, crotalus adamanteus (rattlesnake) venom, and bee venom. only the enzyme from naja naja naja (cobra) venom was found to be activated significantly by phosphorylcholine-containing compounds when hydrolyzing phosphatidylethanolamine. the cobra venom enzyme was also the only one in which these activators induced protein aggregation. the parallel speci ... | 1985 | 4030786 |
| biochemical characterization of two nicotinic receptors from the optic lobe of the chick. | we have studied putative nicotinic acetylcholine receptors in the optic lobe of the newborn chick, using 125i-labeled alpha-bungarotoxin, a specific blocker of acetylcholine receptors in the neuromuscular junction, and [3h]acetylcholine, a ligand which in the presence of atropine selectively labels binding sites of nicotinic character in rat brain cortex (schwartz et al., 1982). [3h]acetylcholine binds reversibly to a single class of high affinity binding sites (kd = 2.2 x 10(-8) m) which occur ... | 1985 | 4055785 |
| contractile response of the isolated dorsal aorta of the snake to angiotensin ii and norepinephrine. | vasopressor action is a phylogenetically old function of angiotensin (ang) ii. the action can be ascribed to both direct activation of vascular ang ii receptors and through catecholamine release. in the rat snake, ptyas korros, the possible presence of common adrenergic-ang receptors and their involvement in this action have been proposed. in order to elucidate the vasopressor mechanism of ang ii in the snake, and to test the presence of common adrenergic-ang receptors, the contractile response ... | 1985 | 4065534 |
| effect of pure venom phospholipase a2 from the central asian cobra (naja naja oxiana eichwald) on oxidative functions of rat liver mitochondria. | 1985 | 4077115 | |
| [central action of snake venoms on body temperature in rats]. | experiments on rats were made to study the effect on the body temperature of the rat of intracerebroventricular injection of venoms of indian cobra, north american rattle snake, and central asian shchitomordnik. it was established that the rise of rectal temperature by 1.5-2.0 degrees c after 90 min was evoked by cobra venom alone. that increase in the body temperature was not prevented by pretreatment with the protein synthesis inhibitors anisomycin or cycloheximide, but was completely abolishe ... | 1985 | 4085638 |
| positional distribution of fatty acids in cardiolipin of mitochondria from 21-day-old rats. | pure cardiolipins (1,3-diphosphatidylglycerol) were prepared from mitochondria of heart, liver and kidney from 21-day-old male wistar rats and submitted to naja naja venom phospholipase a2 (ec 3.1.1.4) action. incubation conditions were controlled carefully, and a complete hydrolysis of cardiolipin to lysocardiolipin (di [1 (1'') acyl sn-glycero-3-phosphoryl] 1',3'-sn-glycerol) and fatty acids from positions 2(2'') was obtained in less than two hr practically without side reactions. cardiolipins ... | 1985 | 4094521 |
| [synthesis of tritium-labeled n,n-dimethyl-2-phenylaziridinium and its reaction with acetylcholinesterase]. | the synthesis of tritium-labeled n,n-demethyl-2-phenylaziridinium has been described. the specific radioactivity of the product obtained was 1,06 tbq/mmole. kinetics of incorporation of this radioactive label into acetylcholinesterase of cobra venom (naja naja oxiana) has been studied at 1,05 mm ligand concentration (25 degrees c, ph 7,50. 0,15 m phosphate buffer). under these conditions two molecules of the radioactive label have been found to react with the enzyme. one molecule incorporates fa ... | 1985 | 4074397 |
| binding of a curarimimetic toxin from cobra venom to the nicotinic acetylcholine receptor. interactions of six biotinyltoxin derivatives with receptor and avidin. | we have reacted n-hydroxysuccinimidyl biotin with the principal curarimimetic toxin in naja naja siamensis venom, biotinylating each of the five lysine residues and the n-terminal isoleucine. the six monobiotinyl-toxins were isolated by ion-exchange chromatography, and the residue modified in each was identified by peptide mapping and amino acid analysis. we evaluated the role of each lysine in the binding of toxin to the acetylcholine receptor by measuring the affinity of each biotinyltoxin for ... | 1985 | 3161881 |
| action of cobra venom phospholipase a2 on large unilamellar vesicles: comparison with small unilamellar vesicles and multibilayers. | phospholipase a2 (naja naja naja) catalyzes the hydrolysis of dipalmitoyl phosphatidylcholine in small unilamellar vesicles (suvs) with a faster initial rate than in large unilamellar vesicles (luvs) and multilamellar vesicles (mlvs). for the suvs, the hydrolysis was initially faster for gel phase than liquid crystalline phase phospholipid. for both luvs and mlvs, hydrolysis was low except in a small temperature range around the thermotropic phase transition of the phospholipid. in this temperat ... | 1985 | 3838567 |
| affinity chromatography of phospholipase a2 from naja naja naja (indian cobra) venom. | a rapid and improved purification procedure is described for phospholipase a2 from the indian cobra, naja naja naja. the procedure is based on affinity chromatography of the venom through affi-gel blue to obtain a 9-fold purification in one step. however, as there are multiple forms of the enzyme in the venom and other proteins do bind to affi-gel blue, further purification is achieved by de-11 cellulose. finally, a minor contaminant is removed by sulfopropyl sephadex c-25 chromatography. the re ... | 1985 | 3927524 |
| adrenergic receptors of isolated snake atria. | cardiac adrenergic receptors in snakes were examined using an isolated atria preparation of naja naja and ptyas korros. treatments included an examination of the atrial responses to selective alpha- and beta-adrenergic agonists and antagonists. in both species, both phenylephrine and isoproterenol produced dose-dependent increases in the atrial beating rate and tension. phenylephrine-induced increases were characterized with a high affinity and low affinity components. these positive chronotropi ... | 1985 | 2861969 |
| amino acid sequence of a cardiotoxin-like basic polypeptide (clbp) with low cytotoxic activity isolated from the venom of the formosan cobra (naja naja atra). | a cardiotoxin-like basic polypeptide, designated as clbp, was isolated from the venom of naja naja atra by gel filtration on sephadex g-50 followed by cm-cellulose chromatography. the cytotoxicity toward yoshida sarcoma cells and lethal toxicity toward mice of clbp were both one-order lower than those of cardiotoxins and cobrotoxin, respectively. clbp is a single polypeptide consisting of 61 amino acid residues with four intramolecular disulfide linkages. the amino acid sequence of clbp shows a ... | 1985 | 4091854 |
| use of some snake venoms in the diagnostics of paroxysmal nocturnal hemoglobinuria (pnh). | the crude toxin of agkistrodon piscivorus was found to produce hemolysis of pnh erythrocytes by way of complement activation, however the degree of pnh blood cell lysis was lower than in other techniques used. the crude toxins of naja naja and naja oxiana cause much higher hemolysis though lower hemolysis takes place in normal blood cells. in some normal persons and different blood diseases it is responsible for high hemolysis even when the complement is absent. from naja naja toxin a fraction c ... | 1985 | 2410338 |
| two new inhibitors of phospholipase a2 produced by penicillium chermesinum. taxonomy, fermentation, isolation, structure determination and biological properties. | plastatin and the known fungal metabolite, luteosporin, have been isolated from fermentations of penicillium chermesinum as inhibitors of porcine pancreatic phospholipase a2 (pla2). structure 1 for plastatin was deduced from its spectroscopic properties. plastatin and luteosporin inhibited pancreatic pla2 competitively with ki values of 0.89 microm and 12.8 microm, respectively. pla2 preparations from naja naja and crotalus adamanteus were not significantly inhibited by plastatin and luteosporin ... | 1985 | 3839502 |
| comparative study on the cardiac actions of bovine parathyroid hormone (1-34). | the cardiac stimulatory effects of bovine parathyroid hormone (1-34) [bpth-(1-34)] were studied on isolated atria and ventricular strips from cobra snakes (naja naja), ducklings (anas platyrhynchos), pigeons (columba livia), japanese quails (coturnix coturnix japonica), laboratory rats (rattus norvegicus), and dogs (canis familiaris). in all atrial preparations, bpth-(1-34) caused positive chronotropism. this suggests that the chronotropic effect of pth is ubiquitous among the terrestrial verteb ... | 1986 | 3940926 |
| effects of beta-bungarotoxin and naja naja atra snake venom phospholipase a2 on acetylcholine release and choline uptake in synaptosomes. | beta-bungarotoxin is a potent presynaptically acting snake venom toxin that exhibits phospholipase a2 activity. we compared the effects of beta-bungarotoxin and a less toxic snake venom phospholipase a2 on synaptosomal 3h-acetylcholine release and 3h-choline uptake. the purpose of these experiments was to study the mode by which beta-bungarotoxin inhibits 3h-acetylcholine release in this preparation. under non-depolarizing conditions, both beta-bungarotoxin and naja naja atra phospholipase a2 st ... | 1986 | 3952766 |
| the relationship between high-affinity noncatalytic binding of snake venom phospholipases a2 to brain synaptic plasma membranes and their central lethal potencies. | the basic phospholipase a2 from naja nigricollis (african spitting cobra) snake venom is enzymatically less active but more toxic than the acidic phospholipase a2 from naja naja atra (taiwan cobra) snake venom, following injection into the right lateral ventricle of the brain of rats. when radiolabeled with 125i, these phospholipases a2 retained enzymatic activities and lethal potencies. both enzymes bound with high affinity and specificity to brain synaptic plasma membrane preparations in vitro ... | 1986 | 3964691 |
| actions of cardiotoxins from the southern chinese cobra (naja naja atra) on rat cardiac tissue. | the cardiotoxic actions of southern chinese cobra (naja naja atra) venom have been investigated. cardiotoxicity accounted for lethality of crude venom in anaesthetized rats and cardiotoxic polypeptides constituted the bulk of the venom when it was fractionated by cm-sephadex chromatography. the cardiotoxic actions of these polypeptides were investigated in isolated cardiac tissue. actions of cardiotoxins on rate, force and intracellular potentials occurred more readily in ventricular tissue and ... | 1986 | 3715895 |
| [reversible inhibition of acetylcholinesterases of different origins by quaternary phosphonium compounds]. | studies have been made on the reversible inhibition of acetylcholinesterase activity from the erythrocytes of man, horse and camel, the electric organ of the skate torpedo marmorata and eel electrophorus electricus, the venom of the snakes naja naja and vipera lebetina, the brain of the pigeon columba livia by tetraphenyl-, triphenylalkyl- and tributyrylalkyl-phosphonium salts. the investigated phosphonium inhibitors exhibit an evident specificity in their action: they were more effective in inh ... | 1986 | 3716682 |
| hypotensive compounds isolated from the dried body of naja naja kaouthia lesson. i. isolation of inosine as a hypotensive principle and structure-activity study of related compounds. | 1986 | 3719873 | |
| effects of modification of tyrosines 3 and 62 (63) on enzymatic and toxicological properties of phospholipases a2 from naja nigricollis and naja naja atra snake venoms. | previously we selectively modified his (48), arg, lys, asp, glu and trp residues in the basic phospholipase a2 from naja nigricollis and the acidic phospholipase a2 from n. n. atra snake venoms. evidence was obtained for the existence of separate but perhaps overlapping sites responsible, respectively, for their enzymatic and pharmacological properties. we have now modified one or two (tyr 3, tyr 62 [63], tyr 3 + 62 [63]) out of the nine tyrosine residues in these enzymes using p-nitrobenzenesul ... | 1986 | 3775785 |
| uncoupling of cholinergic synaptic vesicles by the presynaptic toxin beta-bungarotoxin. | the effect of the presynaptic neurotoxin beta-bungarotoxin (beta-butx) on the acetylcholine (ach) storage system of synaptic vesicles isolated from the electric organ of torpedo californica was studied. the toxin can totally inhibit active transport of [3h]ach by the vesicles in a ca2+-, time-, and concentration-dependent manner. correlated with these effects is a 50-60% stimulation of the vesicle proton-pumping atpase activity. the beta-butx-mediated transport inhibition and atpase stimulation ... | 1986 | 2943872 |
| pancreatic phospholipase a2: isolation of the human gene and cdnas from porcine pancreas and human lung. | oligonucleotide probes synthesized using the published protein sequence for porcine pancreatic phospholipase a2 (pla2; puijk et al., 1977), were used to screen a cdna library made from porcine pancreas. one resulting clone which encoded the entire porcine pla2 enzyme was then used to screen various human cdna and gene libraries. a 562-bp cdna clone from human lung and two overlapping genomic clones encoding the identical transcript were obtained. these clones encoded a 126-residue peptide corres ... | 1986 | 3028739 |
| analysis of ligand binding to the synthetic dodecapeptide 185-196 of the acetylcholine receptor alpha subunit. | a synthetic dodecapeptide corresponding to residues 185-196 of the torpedo acetylcholine receptor alpha subunit, which contains the adjacent cysteine residues at positions 192 and 193, was recently shown by us to contain the essential elements for alpha-bungarotoxin binding. in the present study, we have used sepharose-linked peptides for quantitative analysis of the cholinergic binding properties of this and other synthetic peptides. sepharose-linked peptides corresponding to residues 1-20, 126 ... | 1986 | 3466185 |
| the action of various venoms on escherichia coli. | the antibacterial activity of honeybee venom (apis mellifera), three snake venoms (naja naja sputatrix, vipera russellii and crotalus adamanteus) and the polypeptide melittin was investigated against escherichia coli. minimum inhibitory concentration values, cell lysis and alterations in cell permeability were determined and action against e. coli was in the order: a. mellifera venom greater than melittin greater than n. naja sputatrix venom much greater than v. russellii venom greater than c. a ... | 1986 | 3542922 |
| effects of naja haje (egyptian cobra), naja naja (hooded cobra), naja nigricollis (spitting cobra) and naja mossambica mossambica (mozambique spitting cobra) venoms on the isolated guinea-pig tracheal muscle. | venoms from n. haje, n. naja, n. nigricollis and n. mossambica were tested on the isolated guinea-pig trachea. the four venoms (1-30 micrograms/ml) contracted the tracheal smooth muscle after a delay of 40-60 sec. a second challenge with the venoms caused either no or a much reduced contraction or a relaxant effect. the contraction could be prevented by pretreatment with antihistaminics, but not by atropine, methysergide or indomethacin, indicating that it is due to histamine release by the veno ... | 1986 | 3564065 |
| nicotinic acetylcholine receptor contains multiple binding sites: evidence from binding of alpha-dendrotoxin. | we have studied the stoichiometry of the binding of the long alpha-neurotoxins from the venom of dendroaspis viridis (alpha-dendrotoxin) and naja naja siamensis (alpha-cobratoxin) to the membrane-bound acetylcholine receptor (acchor) from torpedo californica electric organ. the number of toxin molecules bound to one acchor molecule was determined by simultaneous-quantitative gas-phase microsequencing of all the amino acid sequences present in acchor-alpha-neurotoxin complexes. this method permit ... | 1986 | 3462717 |
| self-association and active enzyme forms of naja naja naja and crotalus atrox phospholipase a2 studied by analytical ultracentrifugation. | the dimerization of phospholipase a2 (plpa2) from naja naja naja (pakistani cobra) and crotalus atrox (western diamondback rattlesnake) has been studied from ph 2.5 to 11 at 20 degrees c in 1 mm cacl2, 0.21 m ionic strength. for the c. atrox enzyme, it was found necessary to use a combination of sedimentation equilibrium and fluorescence yield data to analyze the association. sedimentation equilibrium in the analytical ultracentrifuge sufficed for the study of the n. naja plpa2. in the region of ... | 1986 | 3801457 |
| positive response to edrophonium in patients with neurotoxic envenoming by cobras (naja naja philippinensis). a placebo-controlled study. | to study the ability of anticholinesterase drugs to reverse the potentially fatal paralytic effects of cobra venom, we conducted a placebo-controlled, double-blind crossover trial of intravenous edrophonium (tensilon) in 10 adults with neurotoxic envenoming caused by bites of the philippine cobra (naja naja philippinensis). there was significantly more improvement in ptosis and endurance of upward gaze after edrophonium than after placebo. five minutes after injection, the mean difference (+/- s ... | 1986 | 3537783 |
| selectivity and regulation in the phospholipase a2-mediated attack on cholinergic synaptic vesicles by beta-bungarotoxin. | the total fatty acid composition of purified torpedo californica electric organ synaptic vesicles was determined by glc analysis of methyl esters. limit amounts of fatty acids released by high concentrations of either beta-bungarotoxin (beta-butx) or naja naja venom phospholipase a2 (pla2) acting in deoxycholate are reported. the time and enzyme concentration dependence for beta-butx- and pla2-induced release of fatty acids from intact synaptic vesicles indicate that pla2 is 100- to 1,000-fold m ... | 1986 | 3746303 |
| rate-determining step in phospholipase a2 mechanism. 18o isotope exchange determined by 13c nmr. | h2(18)o isotope exchange into specifically 13c-labeled substrate was used to obtain information on the rate-limiting step in the action of the phospholipase a2 from the venom of the indian cobra (naja naja naja). incorporation of 18o was detected by the effect of 18o on 13c chemical shifts in 13c nmr. the enzymatic hydrolysis of a micellar phosphatidylcholine analogue of platelet-activating factor 1-alkyl-2-[1-13c]lauroyl-sn-glycero-3-phosphorylcholine proceeds by an o-acyl cleavage of the sn-2 ... | 1986 | 3745162 |
| 1-stearyl,2-stearoylaminodeoxy phosphatidylcholine, a potent reversible inhibitor of phospholipase a2. | 1-stearyl, 2-stearoylaminodeoxy phosphatidylcholine, a structurally modified phospholipid substrate analog exhibits potent and reversible inhibition of phospholipase a2 from cobra venom (n. naja naja). the apparent ki values determined in two different assay systems employing phosphatidylcholine-surfactant mixed micelles are in reasonable agreement (40 microm and 16 microm) and indicate that the inhibitor binds to the enzyme as much as two orders of magnitude more tightly than does dipalmitoyl p ... | 1986 | 3755338 |
| analysis of folding intermediates from the main toxin of naja naja samarensis containing two blocked cysteines. | the formation of folding intermediates blocked by iodoacetate from the main toxin of naja naja samarensis was monitored by fplc and the populations were identified by amino acid analyses. we have determined conditions allowing for the highest yield in the populations with two blocked cysteines. the free cysteines remaining under these conditions were labeled with iodo[14c]acetate and localized by peptide mapping in one of the products isolated by ion-exchange chromatography (nt3iii). we have als ... | 1986 | 3699158 |
| [effect of modification of naja naja oxiana neurotoxin ii on the stoichiometry of its complexes with acetylcholine receptor]. | it was discovered that illumination of the complex formed by the solubilized acetylcholine receptor from torpedo marmorata and lys25-p-azidobenzoyl derivative of neurotoxin ii results in the appearance on the receptor of up to 4 additional binding sites. acetylcholine and neurotoxin ii, but not the long-chain neurotoxins bind specifically to these sites. the additional binding sites could be also detected after illuminating the receptor complex with other photoactivable derivatives, provided the ... | 1986 | 3718547 |
| characterization of the anticoagulants from taiwan cobra (naja naja atra) snake venom. | taiwan cobra (naja naja atra) snake venom was separated into 19 fractions by means of cm-sephadex c-50 column chromatography. anticoagulant fractions v-vii were refractionated by gel filtration on sephadex g-50 and the purified component possessed phospholipase a2 activity and an inhibitory effect on collagen-induced platelet aggregation. the anticoagulant action could be antagonized by phospholipid or platelet factor 3. anticoagulant fraction xvii was also further refractionated by gel filtrati ... | 1987 | 3576637 |
| different susceptibilities of platelet phospholipids to various phospholipases and modifications induced by thrombin. possible evidence of rearrangement of lipid domains. | on the membrane surface of the human platelet, phosphatidylcholine (pc) and phosphatidylethanolamine (pe) were hydrolyzed to different extents by the snake venom phospholipases a2 of varying pi values. the susceptibility of platelet phospholipids to basic phospholipase a2 of naja nigricollis (pi 10.6) has been reported (wang et al. (1986) biochim. biophys. acta 856, 244-258). the susceptibilities of platelet phospholipids to acidic phospholipase a2 of naja naja atra (pi 5.2) and to neutral phosp ... | 1987 | 3580366 |
| synthesis of prodan-phosphatidylcholine, a new fluorescent probe, and its interactions with pancreatic and snake venom phospholipases a2. | a new fluorescent probe, prodan-pc, was synthesized by incubating thio-pc, a thiol ester analogue of phosphatidylcholine [1,2-bis(decanoylthio)-1,2-dideoxy-sn-glycero-3-phosphocholine], with acrylodan, a fluorescent thiol-reactive reagent [6-acryloyl-2-(dimethylamino)naphthalene], in the presence of phospholipase a2, which served to generate lysothio-pc in situ. prodan-pc (ppc) showed maximum absorption in ethanol at 370 nm. the fluorescence emission spectrum showed maximum emission at 530 nm in ... | 1987 | 3651404 |
| multiple effects of alpha-toxins on the nicotinic acetylcholine receptor. | very low concentrations (5 nm) of alpha-toxin from the venom of naja naja atra produced a characteristic fade in muscle compound action potential and tetanus induced by repetitive nerve stimulation which was identical to the effects of curare. high concentrations of alpha-toxin and all concentrations of alpha-bungarotoxin reduced the response but produced very little fade in comparison to curare. these results suggest that alpha-toxins have more than one effect at the neuromuscular junction. | 1987 | 3691793 |
| 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 |
| enzymatic hydrolysis of short-chain lecithin/long-chain phospholipid unilamellar vesicles: sensitivity of phospholipases to matrix phase state. | short-chain lecithin/long-chain phospholipid unilamellar vesicles (sluvs), unlike pure long-chain lecithin vesicles, are excellent substrates for water-soluble phospholipases. hemolysis assays show that greater than 99.5% of the short-chain lecithin is partitioned in the bilayer. in these binary component vesicles, the short-chain species is the preferred substrate, while the long-chain phospholipid can be treated as an inhibitor (phospholipase c) or poor substrate (phospholipase a2). for phosph ... | 1987 | 3122829 |
| antigenic relatedness between phospholipases a2 from naja naja venom and from mammalian cells. | polyclonal antiserum was prepared against phospholipase a2 from naja naja and used to prepare a purified antibody. it cross-reacted with the antigen, and with intracellular mammalian pla2. this antibody was immunoreactive and inhibited the pla2 activity of naja naja and of guinea pig alveolar macrophages or rat lymphocytes. by immunoblotting, this antiserum revealed one band of pla2 from naja naja (14 kda) and 3 bands for guinea pig alveolar macrophages and rat lymphocytes (30, 45 kda and a mino ... | 1987 | 2443388 |
| monoclonal antibodies against vipera lebetina venom nerve growth factor cross-react with other snake venom nerve growth factors. | nerve growth factor (ngf) was isolated from the venom of vipera lebetina and was purified to homogeneity as judged by sds gel electrophoresis. the biologically active ngf was used to immunize balb/c mouse, and the spleen cells from immunized mouse were fused with mouse pai myeloma cells. forty-seven hybrid cell lines, secreting monoclonal antibodies to v. lebetina ngf, were isolated and nine of them purified from ascitic fluids. the isolated antibodies define two partially overlapping epitopes o ... | 1987 | 2448608 |
| contracture induction by snake venom cardiotoxin in skeletal muscle from humans and rats. | contracture responses to cardiotoxin (ctx) from naja naja kaouthia venom were investigated in rat and human skeletal muscle of similar fiber type distribution to determine species differences in mechanism of action. rat diaphragm strips and human vastus lateralis preparations were directly stimulated in a tissue bath. the calcium dependence of toxin action, synergism between ctx and phospholipase a2 (pla2) activity and roles of na+ + k+-atpase activity and the sarcoplasmic reticulum ca2+ stores ... | 1987 | 3433297 |
| the complete amino acid sequence of a cardiotoxin from the venom of naja naja (cambodian cobra). | the complete amino acid sequence of a small, basic protein with cardiotoxic activity is described. this toxin, designated naja naja f8, was isolated from the venom of naja naja, of cambodian origin, by gel filtration on sephadex g-75 followed by gradient ion exchange chromatography on bio-rex 70. the cardiotoxin f8, molecular weight 6727 from amino acid composition, consists of 60 amino acids in a single peptide chain cross-linked by four disulfide bridges and is devoid of histidine, tryptophan, ... | 1987 | 1148180 |
| the binding site for alpha-bungarotoxin resides in the sequence 188-201 of the alpha-subunit of acetylcholine receptor: structure, conformation and binding characteristics of peptide [lys] 188-201. | in order to study where the binding site of cholinergic agents is in the sequence of the alpha-subunit of nicotinic acetylcholine receptor (achr), we have synthetized 3 peptides with an amino acid sequence corresponding to the following sequences of the alpha-subunit of torpedo californica achr: 125-143, 158-167, [lys] 188-201. for binding studies the peptides were immobilized on sepharose 4b. only the peptide [lys] 188-201 binds 125i-alpha-bungarotoxin (alpha-bgtx) with kd of 1.03 microm. the b ... | 1987 | 3696481 |
| bites by the philippine cobra (naja naja philippinensis): an important cause of death among rice farmers. | we investigated mortality from cobra (naja naja philippinensis) bite among filipino rice farmers. village records in one area were examined and we conducted a careful survey in this and two additional areas among inhabitants at varying risk for snakebite. the death rate from cobra bite was estimated to be as high as 107.1 deaths per 100,000 population per year at one site. most victims were young (median age 17) and 98% were males. only 8% of the victims studied reached a hospital. the confirmed ... | 1987 | 3688317 |
| partial sequence of hemoglobin from cobra (naja naja naja). | hemoglobin from the cobra snake, naja naja naja, was isolated and its chains separated on a cm-cellulose column. the separation profile revealed an alpha and two beta chains having the molar proportions of [alpha]2[beta 1]1[beta 2]1. the n-terminal amino acid sequence of the intact chains and of the cnbr peptides were carried out. the beta 2 chain was found to be heterogeneous comprising a minor component amounting to 11%. this later showed changes at two positions 9 and 14 in the first 30 resid ... | 1987 | 3447643 |
| amino acid sequence of a cytotoxin-like basic protein with low cytotoxic activity from the venom of the thailand cobra naja naja siamensis. | a cytotoxin-like basic protein (clbp) was isolated from the venom of the thailand cobra (naja naja siamensis). the cytotoxicity of clbp toward fl cells was one order of magnitude lower than those of cytotoxins. the amino acid sequence was determined by a combination of conventional methods. the total number of amino acid residues was 62, giving a molecular mass of 6977 da. the sequence at residues 25-30 in the clbp molecule was found to be significantly different from those of cytotoxins. this r ... | 1987 | 3595859 |
| a new ribonuclease from cobra venom (naja naja) showing specificity towards cytidylic acid. | a ribonuclease was isolated and purified to homogeneity from cobra venom. the enzyme was found to be homogeneous on sds and non-sds polyacrylamide gel electrophoreses, and high performance liquid chromatography. the purified enzyme hydrolysed poly(rc), but not poly(ra), poly(ru), poly(rg), poly(ri), or poly(ri).poly(rc). the presence of magnesium was found to be an essential requirement for the nucleolytic activity of this enzyme. | 1987 | 3593367 |
| a one-step isolation procedure for phospholipase a2-free cobra venom factor by fast protein liquid chromatography. | a very rapid and efficient procedure for isolation of cobra venom factor (cof) from naja naja venom is presented. the method is based on mono q anion exchange chromatography on a system for fast protein liquid chromatography (fplc). cof was eluted by a buffer of ph 7.4 at 280 mm salt. a purification of 33.7 x was reached with a yield of at least 27%. contamination with phospholipase was under the detection limit of a sensitive radiometric assay (less than 25 ppm), while the starting material con ... | 1987 | 3819435 |
| effects of cardiotoxin d from naja naja siamensis snake venom upon murine splenic lymphocytes. | cardiotoxin d from naja naja siamensis is cytotoxic to t-lymphocytes above 150 femtomoles/10(6) cells. equivalent lysis of macrophages or b-lymphocytes requires at least 1000 times more toxin. reduction and carboxamidomethylation of cardiotoxin d does not effect t cell lysis. at higher toxin concentrations, 50% t-cell lysis occurs within 10 min. splenocytes cultured with mitogens are up to five times more susceptible to toxin than unstimulated cells. cardiotoxin d may directly disrupt the plasma ... | 1987 | 3433298 |
| enzymatic activities of malayan cobra (naja naja sputatrix) venoms. | the enzymatic activities of four samples of malayan cobra venom were investigated. there was significant variation in the contents of l-amino acid oxidase, alkaline phosphomonoesterase, acetylcholinesterase, phospholipase a, 5'-nucleotidase and hyaluronidase. the phosphodiesterase content was, however, constant. storage of the lyophilized venom powder at 25 degrees c for 1 month did not affect the enzymatic activities. the venom enzymatic activities were generally also stable at 4 degrees c in 0 ... | 1987 | 3433296 |
| depolarization of skeletal muscle cells in culture by a cardiotoxin-like basic polypeptide from the venom of the taiwan cobra (naja naja atra). | a cardiotoxin-like basic polypeptide from the venom of naja naja atra is homologous to cardiotoxins from the same venom, but much less toxic. to determine if it acts like the cardiotoxins its depolarizing ability was measured. it was about 10 times less potent than the cardiotoxins. five amino acids are conserved in the sequences studied, on the exposed second and third loops of the toxin backbone. they may be part of the toxins' interactive site. | 1987 | 3629619 |
| amino acid sequence of a less-cytotoxic basic polypeptide (lcbp) isolated from the venom of the indian cobra (naja naja). | a less-cytotoxic polypeptide, designated as lcbp, was isolated from the venom of naja naja by gel filtration on sephadex g-50 followed by cm-cellulose chromatography. the cytotoxicity toward yoshida sarcoma cells and lethal toxicity toward mice of lcbp were both one order of magnitude lower than that of cytotoxins and that of toxin a, respectively. lcbp is a single polypeptide consisting of 61 amino acid residues with four intramolecular disulfide linkages, and the amino acid sequence is the sam ... | 1987 | 3566773 |
| purification and characterization of an endogenous protein modulator of radioligand binding to "peripheral-type" benzodiazepine receptors and dihydropyridine ca2+-channel antagonist binding sites. | acidified extracts of rat antral stomach chromatographed on octadecylsilane cartridges contained material that inhibited the binding of [3h]ro 5-4864 (4'-chlorodiazepam) and [3h]nitrenidipine to "peripheral-type" benzodiazepine receptors and dihydropyridine ca2+-channel antagonist binding sites respectively. this material reduced the apparent affinities of both radioligands without significantly affecting the maximum number of binding sites. in contrast, the binding of [3h]diazepam, [3h]ro 15-17 ... | 1988 | 2829915 |
| regulation of gamma-aminobutyric acid/barbiturate receptor-gated chloride ion flux in brain vesicles by phospholipase a2: possible role of oxygen radicals. | preincubation of brain membranes with phospholipase a2 (pla2) has been shown previously to affect the binding characteristics of various recognition sites associated with the gamma-aminobutyric acid (gaba) receptor complex. in the present study, we have investigated the effects of pla2 (from naja naja siamensis venom) on the functional activity of the gaba receptor/chloride ion channel. pla2 (0.001-0.02 u/mg protein) preincubation decreased pentobarbital-induced 36cl- efflux and muscimol-induced ... | 1988 | 2447244 |
| site-specific epsilon-nh2 monoacylation of pancreatic phospholipase a2. 2. transformation of soluble phospholipase a2 into a highly penetrating "membrane-bound" form. | long-chain lecithins present in bilayer structures like vesicles or membranes are only very poor substrates for pancreatic phospholipases a2. this is probably due to the fact that pancreatic phospholipases a2 cannot penetrate into the densely packed bilayer structures. to improve the weak penetrating properties of pancreatic phospholipases a2, we prepared and characterized a number of pancreatic phospholipase a2 mutants that have various long acyl chains linked covalently to lys116 in porcine an ... | 1988 | 3130102 |
| [modulation of the m-cholinergic reaction by the venom of the central asian cobra (naja naja oxiana)]. | the effect of the central asian cobra's (naja naja oxiana) poison upon cholinergic response of isolated small intestine was studied in the wistar rats. the effect involved a significant activation by 30-70 per cent of m-cholinergic response in the type of "noncompetitive" interaction. the modulating effect of the poison is supposed to occur due to changes in cytoplasmatic membrane. | 1988 | 3181518 |