The active components of crotoxin

Horst, J.; Hendon, R.A.; Fraenkel‐Conrat, H.

doi:10.1016/s0006-291x(72)80077-9

Cited by 59 publications

(14 citation statements)

References 7 publications

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“…Horst et al [38] reported a pZ of 3.7 and found some microheterogeneities which we could not detect in our material. The crotalus phospholipase A was highly basic in focusing experiments.…”

Section: Discussioncontrasting

confidence: 83%

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Biochemistry and Pharmacology of the Crotoxin Complex

Breithaupt

Rübsamen

Habermann

1974

European Journal of Biochemistry

102

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Crotapotin and the basic crotalus phospholipase A, which are the main components of the crotoxin complex, have been purified to homogeneity with respect to their behaviour on polyacrylamide gel electrophoresis, cellogel electrophoresis, immunoelectrophoresis, isoelectric focusing, and sedimentation equilibrium analysis.The isoelectric points were found to be 3.4 for crotapotin and 9.7 for the crotalus phospholipase A. The molecular weight of phospholipase A has been determined by gel filtration in 6 M guanidine . HCl (14 500), by ultracentrifugation (15 SOO), and by dodecylsulfate-gel electrophoresis (15 800). Phospholipase A consists of a single peptide chain intramolecularly crosslinked by eight disulfide bridges.The molecular weight of crotapotin was 8900 as shown by gel filtration in 6 M guanidine . HCl. Sedimentation equilibrium studies in 4 M guanidine . HCl gave a value of 6700. In solutions of lower ionic strength, the MI was 12 500, indicating that crotapotin can exist as a dimer. In contrast the M , of reduced and carboxamidomethylated crotapotin was much lower (4000 -4500), in gel filtration experiments.Crotapotin consists of three peptide chains, held together by disulfide bridges. Chain A contains 40 amino acid residues (MI 4274), chain B 34 residues (MI 3658) and chain C 14 residues (MI 1558). A free NH,-terminal residue (serine) could be detected only for chain A.The main toxic compound of the Crotalus terrificus venom, crotoxin, can be separated by chromatography on cilrboxymethyl cellulose into two basic phospholipases A with low toxicity, and the acidic crotapotin as reported by Habermann and Riibsamen [l], Breithaupt et al. [2] and Rubsamen et al. [3]. confirmed our results concerning the fractionation and recombination of the crotoxin complex. The acidic protein, which we have called crotapotin, lacks the toxicity and the enzymatic activity of crotoxin, but potentiates the toxicity and inhibits the enzymatic activities of the crotalus phospholipase A. The potentiating of the toxicity of phospholipase A was thought to be due to alteredThe previous two, papers in this series have appeared elsewhere [3,5]. A short outline of this paper was presented

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“…Horst et al [38] reported a pZ of 3.7 and found some microheterogeneities which we could not detect in our material. The crotalus phospholipase A was highly basic in focusing experiments.…”

Section: Discussioncontrasting

confidence: 83%

“…We measured a p I of 9.7, using a shallow pH gradient. The lower p l of 8.6 found by Horst et al [38] may be due to adsorption in the polyacrylamide gel.…”

Section: Discussionmentioning

confidence: 70%

Biochemistry and Pharmacology of the Crotoxin Complex

Breithaupt

Rübsamen

Habermann

1974

European Journal of Biochemistry

102

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“…It is a complex of two distinct protein subunits [2,3] : a strongly basic component (component B, M , 12000) which carries the phospholipase activity and an acidic protein (component A, M , 10000) which has no enzymatic activity and is not toxic by itself. Whereas the isolated subunits are either not or only a little toxic, they recombine into a complex which exhibits the same toxicity as the original material [4,5].The lethal effect of crotoxin has generally been attributed to a presynaptic blockage of the neuromuscular transmission [6]. At this level, it causes a reduction of acetylcholine release by the nerve terminals similar to that observed with /l-bungarotoxin [7], notexin [8,9] and taipoxin [lo].…”

mentioning

confidence: 99%

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confidence: 99%

Postsynaptic Effects of Crotoxin and of Its Isolated Subunits

Bon

Changeux

Jeng

et al. 1979

European Journal of Biochemistry

209

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Crotoxin is a potent neurotoxin from the venom of Crotalus durissus terrificus. It is composed of two subunits: a basic phospholipase A2 with low toxicity (component B) and an acidic protein seemingly devoid of intrinsic biological activity (component A). Crotoxin and its isolated phospholipase subunit block the depolarisation caused by cholinergic agonists on the isolated electroplaque from Electrophorus electricus. The other component, which is inactive when applied alone, enhances the pharmacological activity of the phospholipase when the two components are used together. Crotoxin also blocks the increase of z2Na+ efflux caused by carbamylcholine from excitable microsacs prepared from Torpedo marmorata electric organ. Crotoxin therefore acts postsynaptically, but does not interfere with the binding of a-toxin from Nu@ nigricollis to the nicotinic cholinergic receptor site. Instead, like local anesthetics, it stabilizes a desensitized form of the acetylcholine receptor characterized by its high affinity for agonists. The phospholipase component B binds in a nonsaturable manner to receptor-rich membranes. In contrast, component A does not bind to acetylcholine receptor-rich membranes, but completely prevents the non-saturable binding of component B. When the two components are applied together, a saturable binding of the latter is observed with the acetylcholine receptor-rich membranes.Crotoxin, the major component of the brazilian rattle-snake (Crotalus durissus terrificus) venom is a very potent neurotoxin which possesses a phospholipase activity [l]. It is a complex of two distinct protein subunits [2,3] : a strongly basic component (component B, M , 12000) which carries the phospholipase activity and an acidic protein (component A, M , 10000) which has no enzymatic activity and is not toxic by itself. Whereas the isolated subunits are either not or only a little toxic, they recombine into a complex which exhibits the same toxicity as the original material [4,5].The lethal effect of crotoxin has generally been attributed to a presynaptic blockage of the neuromuscular transmission [6]. At this level, it causes a reduction of acetylcholine release by the nerve terminals similar to that observed with /l-bungarotoxin [7], notexin [8,9] and taipoxin [lo]. However, having observed a depression of the response to acetylcholine of the isolated denervated rat diaphragm, VitalBrazil [ l l ] concluded that crotoxin also acts at the postsynaptic level in the mammals. In order to examine a possible postsynaptic action of crotoxin without interference with its presynaptic action, we studied the effect of crotoxin on two postsynapticEnzyme. Phospholipase A2 (EC 3.1.1.4) preparations : the isolated electroplaque from Electrophorus electricus and the acetylcholine receptor-rich membranes from Torpedo marmorata. Crotoxin affects the response of both preparations to cholinergic agonists, and our observations suggest how interactions between the two subunits increase the pharmacological effect of the phospholipase component...

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“…This toxin is a noncovalent oligomer, formed by two subunits: one acid and the other basic. The latter has phospholipase A2 activity and is neurotoxic, while the acid subunit is enzymatically and pharmacologically inactive, but it highly increases the toxicity of the basic subunit (2,3) . The acid subunit acts as a helper to the basic subunit, giving it specificity and increasing its stability.…”

Section: Introductionmentioning

confidence: 99%

Study of crotoxin on the induction of paralysis in extraocular muscle in animal model

Ribeiro

Almeida

Velarde

et al. 2012

Arq. Bras. Oftalmol.

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Purpose: Crotoxin is the major toxin of the venom of the South American rattlesnake Crotalus durissus terrificus, capable of causing a blockade of the neurotransmitters at the neuromuscular junction. The objective of this study was to appraise the action and effectiveness of the crotoxin induced paralysis of the extraocular muscle and to compare its effects with the botulinum toxin type A (BT-A). Methods: The crotoxin, with LD50 of 1.5 μg, was injected into the superior rectus muscle in ten New Zealand rabbits. The concentration variance was 0.015 up to 150 μg. Two rabbits received 2 units of botulinum toxin type A for comparative analysis. The evaluation of the paralysis was performed using serial electromyography. After the functional recovery of the muscles, which occurred after two months, six rabbits were sacrificed for anatomopathology study. Results:The animals did not show any evidence of systemic toxicity. Transitory ptosis was observed in almost every animal and remained up to fourteen days. These toxins caused immediate blockade of the electrical potentials. The recovery was gradual in the average of one month with regeneration signs evident on the electromyography. The paralysis effect of the crotoxin on the muscle was proportional to its concentration. The changes with 1.5 μg crotoxin were similar to those produced by the botulinum toxin type A. The histopathology findings were localized to the site of the injection. No signs of muscle fiber's necrosis were seen in any sample. The alterations induced by crotoxin were also proportional to the concentration and similar to botulinum toxin type A in concentration of 1.5 μg. Conclusion: Crotoxin was able to induce transitory paralysis of the superior rectus muscle. This effect was characterized by reduction of action potentials and non-specific signs of fibrillation. Crotoxin, in concentration of 1.5 μg was able to induce similar effects as botulinum toxin type A. Keywords

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The active components of crotoxin

Cited by 59 publications

References 7 publications

Biochemistry and Pharmacology of the Crotoxin Complex

Biochemistry and Pharmacology of the Crotoxin Complex

Postsynaptic Effects of Crotoxin and of Its Isolated Subunits

Study of crotoxin on the induction of paralysis in extraocular muscle in animal model

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