Crotoxin, the neurotoxin of South American rattlesnake venom, is a presynaptic toxin acting like...
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Toxiron, 1978, Vol . !6, pp. 203-206. Peraarnon Preas . Printed in Great Britain i~L~V i r .W S CHluxc Ctu nc, C. and Doxc LEE, J . (Pharmacological Institute, College of Medicine, National Taiwan University, Taipei, Taiwan) . Crotoxin, the neurotoxin of South American rattlesnake venom, is a presynaptic toxin acting like ß-bungarotoxin . Naursyn-Schmiedebergs Arch . Pharmacol. 296, 159 (1977) . CxotoxtN was the first "newotoxin'", which was isolated in 1938 by Slotta and Fraenkl Conrat from the venom of the solenoglyphas, Crotalus durissus terrificus . Its chemical and biochemical properties are mark- edly different from the short and long "ncurotoxins" of proteroglyphae venoms . Crotoxin resembles the phospholipase A active "neurotoxins" of Australian elapids and ß-bungarotoxin . These toxins act on the presynaptic site, inhibiting the release of neurotransmitter . For further investigations the authors isolated crotoxin not by the original method but by chromato- graphic procedures . They studied its neuromuscular blocking actions on isolated preparations, its direct effect on muscles, its effects on the response to exogenous acetylcholine, the effects on the frequency and amplitude of miniature endplate potentials, its toxicity and cause of death . The results of these experiments are very similar to those of ß-bungarotoxin . The authors suggest, therefore, a presynaptic interference of crotoxin with the release of acetylcholine from the motor nerve terminals perhaps via the phospholipase A activity . H .M . JOUHERT, F. J . (National Chemical Research Laboratory, Pretoria 0001, South Africa). Snake venom toxins . The amino acid sequence of three toxins (CM-2e, CM~a and CM-71 from Naja hale anrsulifera (Egyptian cobra venom) . Hoppe-Seylers Z . Physiol . Chem . 357, 1735-1750 (1976) . THE vEKOM of the Egyptian cobra was fractionated by a combination of gel filtration on Sephadex G SU and ion exchange chromatography on CM-cellulose . Three toxins were obtained and called CM-2e, CM-4a, and CM-7. Their molecular weights were calculated from gel filtration as 8600, 8700 and 8000 and from amino acid composition as 6642, 6655 and 6786 . The differences are thought to be due to association equilibria between monomers and dieters in gel filtration. The t.n, e (i .v ., mouse) was relatively high : 490 ~ 0"26, 414 ~ 028 and 2" 60 f 0" 14 mg/kg mouse ; therefore the toxins may belong to the "cytotoxin" group. This is also evident from their immunochemical cross-reactivity . After reduction and S-carboxymethylation, the peptides were digested with trypsin and chymotrypsin, and also subjected to direct automated sequencing . The peptides were separated by chromatography on DEAE cellulose and purified either by paper chromato- graphy with butanol-pyridine-acetic acid-water, or by paper electrophoresis at pH 4" 5. The peptides were sequenced either manually or by the automated Edman procedure . The toxins are highly homologous among themselves and with the previously sequenced toxins Vttl, CM-8 and CM-8A . Considering the sequence of all six toxins, there are only 13 variant amino acids from a total of 60 . The N-terminus is always Leu-, the C-terminus Cys-Asn OH . The eight half-cystines are always in the disulfide form . E.H . Ci-IANDRASEKHARAREDDY, D. and PADMANABHA N.unu, B. (SRI Venkateswara University, Department of Zoology, Tirupati 517502, Andhra Pradesh, India) . Diurnal rhythmic activity of alkaline phosphatase in scorpion Heterometrus fulvipes . C. Koch . Curr. Sci . 46, 147-148 (1977) . THE DNRNAL Chânges in alkaline phosphatase content of the hepatopanereas, heart and pedipalpal muscle of the scorpion, Heterometrus julvipes, were investigated . A diurnal rhythm (maximum at 20 hr, minimum at 08 hr), similar to the daily changes in dehydrogenases and esterases content was observed " A.v .H . 203
Transcript of Crotoxin, the neurotoxin of South American rattlesnake venom, is a presynaptic toxin acting like...
Toxiron, 1978, Vol. !6, pp. 203-206. Peraarnon Preas . Printed in Great Britain
i~L~Vi r .WS
CHluxc Ctu nc, C. and Doxc LEE, J. (Pharmacological Institute, College of Medicine,National Taiwan University, Taipei, Taiwan). Crotoxin, the neurotoxin of South Americanrattlesnake venom, is a presynaptic toxin acting like ß-bungarotoxin . Naursyn-Schmiedebergs
Arch . Pharmacol. 296, 159 (1977) .
CxotoxtN was the first "newotoxin'", which was isolated in 1938 by Slotta and Fraenkl Conrat from thevenom of the solenoglyphas, Crotalus durissus terrificus . Its chemical and biochemical properties are mark-edly different from the short and long "ncurotoxins" of proteroglyphae venoms . Crotoxin resembles thephospholipase A active "neurotoxins" of Australian elapids and ß-bungarotoxin . These toxins act on thepresynaptic site, inhibiting the release of neurotransmitter .
For further investigations the authors isolated crotoxin not by the original method but by chromato-graphic procedures . They studied its neuromuscular blocking actions on isolated preparations, its directeffect on muscles, its effects on the response to exogenous acetylcholine, the effects on the frequency andamplitude of miniature endplate potentials, its toxicity and cause of death.
The results of these experiments are very similar to those of ß-bungarotoxin . The authors suggest,therefore, a presynaptic interference of crotoxin with the release of acetylcholine from the motor nerveterminals perhaps via the phospholipase A activity .
H.M .
JOUHERT, F. J. (National Chemical Research Laboratory, Pretoria 0001, South Africa). Snakevenom toxins . The amino acid sequence of three toxins (CM-2e, CM~a and CM-71 fromNaja hale anrsulifera (Egyptian cobra venom) . Hoppe-Seylers Z. Physiol . Chem . 357, 1735-1750
(1976) .
THE vEKOM of the Egyptian cobra was fractionated by a combination of gel filtration on Sephadex G SUand ion exchange chromatography on CM-cellulose . Three toxins were obtained and called CM-2e, CM-4a,and CM-7. Their molecular weights were calculated from gel filtration as 8600, 8700 and 8000 and fromamino acid composition as 6642, 6655 and 6786 .The differences are thought to be due to association equilibriabetween monomers and dieters in gel filtration. The t.n,e (i .v ., mouse) was relatively high : 490 ~ 0"26,414 ~ 028and 2 "60 f 0"14 mg/kg mouse ; therefore the toxins may belong to the "cytotoxin" group. Thisis also evident from their immunochemical cross-reactivity . After reduction and S-carboxymethylation, thepeptides were digested with trypsin and chymotrypsin, and also subjected to direct automated sequencing .The peptides were separated by chromatography on DEAE cellulose and purified either by paper chromato-graphy with butanol-pyridine-acetic acid-water, or by paper electrophoresis at pH 4"5. The peptides weresequenced either manually or by the automated Edman procedure . The toxins are highly homologousamong themselves and with the previously sequenced toxins Vttl, CM-8 and CM-8A. Considering thesequence of all six toxins, there are only 13 variant amino acids from a total of 60 . The N-terminus isalways Leu-, the C-terminus Cys-Asn OH. The eight half-cystines are always in the disulfide form .
E.H .
Ci-IANDRASEKHARAREDDY, D. and PADMANABHA N.unu, B. (SRI Venkateswara University,Department of Zoology, Tirupati 517502, Andhra Pradesh, India) . Diurnal rhythmic activityof alkaline phosphatase in scorpion Heterometrus fulvipes . C. Koch . Curr. Sci. 46, 147-148
(1977) .
THE DNRNAL Chânges in alkaline phosphatase content of the hepatopanereas, heart and pedipalpal muscleof the scorpion, Heterometrus julvipes, were investigated . A diurnal rhythm (maximum at 20 hr, minimumat 08 hr), similar to the daily changes in dehydrogenases and esterases content was observed "
A.v.H .
203
