Xylarinase: a novel clot busting enzyme from an endophytic fungus Xylaria curta.

Xylarinase is a bi-functional fibrinolytic metalloprotease isolated from the culture filtrate of endophytic fungus Xylaria curta which is monomeric with a molecular mass of similar to 33.76 kDa. The enzyme displayed both plasmin and tissue plasminogen activator like activity under in vitro conditions. It hydrolyses A alpha and B beta chains of the fibrinogen. Optimal fibrinolytic activity of xylarinase is observed at 35 degrees C, pH 8. Ca2+ stimulated the fibrinolytic activity of xylarinase while Fe2+ and Zn2+ inhibited suggesting it to be a metalloprotease. The K-m and V-max values of xylarinase were 240.9 mu M and 1.10 U/ml for fibrinogen and 246 mu M and 1.22 U/ml for fibrin, respectively. Xylarinase was found to prolong the activated partial thromboplastin time and prothrombin time. The N-terminal sequence of xylarinase (SNGPLPGGVVWAG) did not show any homology with previously known fibrinolytic enzymes. Thus xylarinase is a novel fibrinolytic metalloprotease which could be possibly used as a new clot busting enzyme.