Purification and characterization of brevinase, a heterogeneous two-chain fibrinolytic enzyme from the venom of Korean snake, Agkistrodon blomhoffii brevicaudus.

A fibrinolytic enzyme, designated as brevinase, was purified from the venom of Korean snake, Agkistrodon blomhoffii brevicaudus. Brevinase cleaved both the Aalpha- and Bbeta-chains of fibrinogen but did not affect the gamma-chain. It showed beta-fibrinogenase activity devoid of fibrinogen clotting and caseinolytic activity. The fibrinolytic activity was completely inhibited by PMSF, DFP, Pefabloc, and DTT, indicating brevinase is a serine protease requiring disulfide bridge(s) for its activity. It kept 80% of the initial activity after heating at 100 degrees C for 3 min, showed an equal maximum activity in the pH range from 5.5 to 8.5, and was inactivated by Zn(2+). Brevinase consists of two polypeptide chains of 16.5 and 17 kDa linked by disulfide bridge(s). The N-terminal amino acid sequences of 16.5 and 17 kDa chains showed homology to the N-terminal and the internal (central region) amino acid sequences of single-chain fibrinolytic enzymes in snake venom, respectively.