ISOLATION AND PROPERTIES OF SERINE PROTEINASE PC OF KAMCHATKA CRAB PARALITHODES CAMTSCHATICA - A PROTEOLYTIC-ENZYME OF BROAD-SPECIFICITY

Homogenous serine proteinase PC was isolated with 68% yield from the h epatopancreas of the Kamchatka crab Paralithodes camtschatica by affin ity chromatography on arginine-agarose and PTG-Sepharose and ion-excha nge chromatography on Mono Q. The proteinase is completely inhibited b y diisopropyl fluorophosphate-a specific inhibitor of serine proteinas es. Its molecular mass is 29 kD, and its pi is 3.0. The proteinase cle aves Glp-Phe-Ala-pNA optimally at pH 7.5 and 47-55 degrees C (K-m 0.83 mM, k(cat) = 67 sec(-1)). The enzyme is stable at pH 4-9. Proteinase PC has broad substrate specificity, cleaving in peptides and proteins the peptide bonds formed by the carboxyl group of hydrophobic amino ac ids, arginine, and lysine. It hydrolyzes fibrin and collagen. Its N-te rminal sequence IVGGQEATP reveals 90% of coincidence with those of col lagenolytic proteinases from other crab species.