Its target is unknown, but this toxin may modulate voltage-activated calcium channels (Cav) or calcium-dependent potassium channels (KCa). Expressed by the venom duct. The cysteine framework is C-C. D-chirality of Trp-58 ('Trp-3' in the mature Contryphan-Vc2 peptide) seems to be only protective against proteolytic degradation, since [L-Trp3]-contryphan-Vc2 is degraded by trypsin within 4 hours, while [D-Trp3]-contryphan-Vc2 is not affected and the toxicity of both [D-Trp3]- and [L-Trp3]-contryphan-Vc2 is similar when intractranially injected into mice (PubMed:28216409). It is also noteworthy that neither [D-Trp3]- nor [L-Trp3]-contryphan-Vc2 is susceptible to cleavage by pepsin or alpha-chymotrypsin over the 4 hours duration of the assay (PubMed:28216409). Exists in two forms, due to cis-trans isomerization at 59-Thr-Pro-60. The trans conformation is the major form, with a cis:trans ratio of 1:5. Belongs to the O2 superfamily. Contryphan family.