Characterization of kallikrein-like enzyme from Crotalus ruber ruber (red rattlesnake) venom.

1. A kallikrein-like enzyme from the venom of Crotalus ruber ruber (red rattlesnake) had been isolated and characterized by Mori and Sugihara. The enzyme was active upon the kallikrein substrates, Pro-Phe-Arg-MCA and z-Phe-Arg-MCA, and slightly hydrolyzed Boc-Val-Leu-Lys-MCA, and Boc-Phe-Ser-Arg-MCA. 2. Unlike thrombin, the newly isolated kallikrein-like enzyme did not cause formation of a fibrin clot when fibrinogen was mixed with the enzyme. 3. The B beta chain of fibrinogen was first split and A alpha chain was cleaved later. Pancreatic kallikrein hydrolyzed only the A alpha chain without affecting the B beta chain. 4. The kallikrein-like enzyme produced kallidin (Lys-bradykinin) by splitting the Met-Lys bond instead of producing bradykinin. 5. The kallikrein analog JSI-450 (Ac-Phe-Ser-Pro-Phe-Arg-Ser-Val-Gln-Val-Ser-NH2) was also cleaved at the site of the Arg-Ser bond. 6. Its NH2-terminal amino acid sequence (Val-Ile-Gly-Gly-Asp-Glu-Cys-Asn-Ile-Asn-Glu-Arg-Pro-Phe-Leu-Val-Ala-Leu-Tyr- Asp-Ser-) is homologous to the rat pancreatic kallikrein and other snake venom proteases.