Snake venom myotoxin (Lys49 phospholipase A2 homologue and crotamine) (SVM)

Myotoxins from Bothrops asper and Crotalus durissus are specialized venom proteins that induce rapid and severe skeletal muscle damage. In B. asper, the primary non-enzymatic myotoxins are Lys49 phospholipase A2 (PLA2) homologues, such as Myotoxin II, which lack catalytic activity but disrupt cell membranes through a direct physical mechanism involving their C-terminal cationic and hydrophobic residues (Lomonte et al., 2009, PMID: 19162151). In C. durissus, the venom contains crotamine, a small basic myotoxin that targets voltage-gated sodium channels, leading to muscle fasciculations and necrosis (Ogni et al., 2016, PMID: 27153457). These proteins are critical targets for therapeutic intervention because they are responsible for the permanent tissue loss and disability often associated with snakebites (Gutiérrez et al., 2017, PMID: 28914610). While traditional antivenoms are the standard of care, their effectiveness against local myonecrosis is limited by the speed of toxin action, prompting research into small-molecule inhibitors like varespladib or heparin-like polyanions that can neutralize these toxins more rapidly at the site of envenomation (Bryan-Quirós et al., 2019, PMID: 31108907).

Other names

Lys49 PLA2 homologueNon-enzymatic phospholipase A2Basic myotoxinCrotamineMyotoxin II (Bothrops asper)Small basic myotoxin

Neutralization of toxic activity through antibody binding (antivenom) or competitive inhibition of membrane-binding sites by small molecules or polyanions.