Hydrolytic specificity of three basic proteinases isolated from the venom of Bothrops moojeni for the B-chain of oxidized insulin.

The hydrolytic activity of three basic proteinases isolated from Bothrops moojeni venom was determined on the B-chain of oxidized insulin. The serine proteinases MSP1 and MSP2 cleave the insulin B-chain at identical positions and in the same order of bond cleavage. Cleavage occurs first at the Arg-Gly(22-23) position, followed by hydrolysis of the Lys-Ala(29-30) peptide bond. The metalloproteinase MPB differs from the serine proteinases in cleaving the insulin B-chain very rapidly at four positions: Ser-His(9-10), Ala-Leu(14-15), Tyr-Leu(16-17) and Phe-Phe(24-25).