Purification and characterization of alpha-mucrofibrase, a novel serine protease with alpha-fibrinogenase activity from the venom of Chinese Habu (Trimeresurus mucrosquamatus).

A novel fibrinogenolytic protease, named alpha-mucrofibrase, was purified from the venom of Chinese Habu (Trimeresurus mucrosquamatus) by DEAE-Sephadex A-50 ion-exchange chromatography and Sephadex G-100 (super fine) gel filtration alpha-Mucrofibrase is a single-chain polypeptide of approximately 29 kDa. It is stable even at 95 degrees C, and the most susceptible hydrolysis substrate is S-2302. It cleaved primarily the Aalpha chain of fibrinogen followed by the Bbeta chain, while the gamma chain was partially affected. N-terminal sequence of this fibrinogenolytic enzyme has great homology with those of other snake venom serine proteases. The esterase activity of alpha-mucrofibrase is inhibited by phenylmethylsulfonyl fluoride (PMSF) but not by metal chelator (EDTA), suggesting this fibrinogenase belongs to the venom serine protease family.