A new muscle damaging toxin, myotoxin II, from the venom of the snake Bothrops asper (terciopelo)

Abstract

A new muscle damaging toxin, myotoxin II, was purified from the venom of Bothrops asper by ion-exchange chromatography on CMSephadex C-25. The toxin is a dimeric, basic protein with a monomer mol.wt of 13,341, according to the amino acid composition, and 16,000 on the basis of SDS-polyacrylamide gel electrophoretic mobility . It has a high number of aspartate and lysine residues, as well as of hydrophobic amino acids. Upon i.m. injection into mice, the toxin induces myonecrosis and increase in serum creatine kinase levels . In addition, myotoxin II induces edema in the mouse foot pad. Immunochemical tests, mol.wt, and amino acid composition indicate a high degree ofhomology between myotoxin II and a previously characterized myotoxin from this venom, myotoxin I. However, in contrast to myotoxin I, myotoxin II lacks phospholipase A2 and anticoagulant activities in vitro.