The primary structure of crotalase,a thrombin-like venom enzyme,exhibits closer homology to kallikrein than to other serine proteases

Amino acid sequences of crotalase, totaling 98 residues or about 37% of the molecule, were determined by Edman degradation and were compared with the published sequences of nine serine proteases. Homologous alignment could be found for all crotalase sequences except one decapeptide. Comparison between crotalase and porcine pancreatic kallikrein showed the largest number of identical amino acids (36%). This finding has led to experiments which demonstrate that crotalase has specific enzymatic properties resembling kallikrein.