Purification and characterization of a novel fibrinolytic enzyme from fruiting bodies of Korean Cordyceps militaris.

A fibrinolytic enzyme has been purified from the fruiting bodies of Korean Cordyceps militaris. The molecular mass of the enzyme was estimated to be 34 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), fibrin-zymography, and gel filtration chromatography. The 15 amino acid residues of the N-terminal sequence of the enzyme were APVEQCDAPVGLARL, which is dissimilar to those of fibrinolytic enzymes from other mushrooms. Optimal pH and temperature values of the enzyme were 7.0 and 40°C, respectively. The enzyme activity was completely inhibited by phenylmethylsulfonyl fluoride (PMSF), TPCK, 1,10-phenanthroline, Cu(2+), and Ba(2+). It was also significantly inhibited by aprotinin, EDTA, and EGTA. The enzyme showed a higher specificity for a synthetic substrate, N-succinyl-Ala-Ala-Pro-Phe-p-nitroanilide, exhibiting that it is a chymotrypsin-like serine metalloprotease. The enzyme preferentially hydrolyzed the fibrinogen Aα-, followed by the Bβ-chains and the γ-chain. The α, β, and γ-γ chains of fibrin were also degraded by the enzyme.