Reversible neuromuscular blocking action of carbohymethylated α-bungarotoxin

Carbanidomethylation of the reduced Cys 29-Cys 33 bridge of α-bungarotoxin ( Bungarus multicinctus postsynaptic neurotoxin) did not alter the LD 50 or irreversibility of the toxin, while carboxymethylated α-bungarotoxin was less potent and its neuromuscular blocking action in mouse diaphragm was rev...

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Bibliographic Details
Published inBiochimica et biophysica acta. General subjects Vol. 755; no. 2; pp. 210 - 216
Main Authors Chewn-Lang Ho, Shih-Hsiung Wu, Charng-Jui Chen
Format Journal Article
LanguageEnglish
Published Elsevier B.V 25.01.1983
Subjects
Acetylcholine receptor
Bungarotoxin
Carboxymethylation
Circular dichroism
Neurotoxin
Carboxymethylation
Bungarotoxin
Acetylcholine receptor
Neurotoxin
Circular dichroism
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Summary:Carbanidomethylation of the reduced Cys 29-Cys 33 bridge of α-bungarotoxin ( Bungarus multicinctus postsynaptic neurotoxin) did not alter the LD 50 or irreversibility of the toxin, while carboxymethylated α-bungarotoxin was less potent and its neuromuscular blocking action in mouse diaphragm was reversible. The circular dichroic spectra of both modified toxins were similar but slightly different from that of native toxin. Neuromuscular transmission in the chick biventer cervicis nerve-muscle preparation could be blocked by the carboxymethylated toxin, and reactivated by washing, whereas the response of the muscle to extrinsic acetylcholine could also be blocked but was hardly restored by washing. These results suggest that carboxymethylated toxin can differentiate between junctional and extrajunctional acetylcholine receptors in chick skeletal muscle.
ISSN:0304-4165
1872-8006
DOI:10.1016/0304-4165(83)90205-2