Purification and characterization of a non-hemorrhagic metalloprotease from Agkistrodon halys brevicaudus venom

A non-hemorrhagic metalloprotease (protease L4) was purified from the venom of Chinese Mamushi ( Agkistrodon halys brevicaudus ) by gel filtration and anion-exchange chromatography. Protease L4 has the molecular weight of 22 000 and its optimum pH was 8.5. The protein was stable in the pH range of 5–9 and below 40°C. The proteolytic activity was inhibited by metal-chelating agents and some metal ions. Calcium ion activated the activity dose-dependently, but had only a minor effect on the thermal and pH stability. L4 showed fibrinogenase activity, hydrolyzing only the A a chain of fibrinogen. The protease cleaved preferentially at the N-terminal of Leu and His residues of some peptides.