Inhibition of the proteolytic activity of hemorrhagin-e from Crotalus atrox venom by antihemorrhagins from homologous serum

Antihemorrhagic proteins from Crotalus atrox serum were tested for their ability to inhibit the proteolytic activity of the hemorrhagic toxin-e from Crotalus atrox venom and of several other proteolytic enzymes: trypsin, collagenase and thermolysin. The antihemorrhagic proteins inhibited the proteolytic activity of hemorrhagin-e when tested on gelatin type I and collagen type IV, the proteolytic activity of trypsin on photofilm gelatin and the proteolytic activity of whole venom when tested on azocollagen and photofilm gelatin. The antihemorrhagins failed to inhibit the proteolytic activity of trypsin when tested on the specific synthetic substrate N-acetyl-dl-phenylalanine-β-naphthyl ester (APNE), the activity of microbial collagenase on N-(3-[2-furyl]acryloyl)-Leu-Gly-Pro-Ala (FALGPA) or on azocollagen and the activity of thermolysin on N-(3-[2-furyl] acryloyl)-Gly-Leu amide (FAGLA). It is tentatively suggested that the antihemorrhagins from snake blood serum are proteinase inhibitors that under-went specialization towards the neutralization of the proteolytic activity of hemorrhagic toxins.