ANTIPLASMIN CLEAVING ENZYME

摘要

Human alpha₂-antiplasmin (alpha₂AP) is the major inhibitor of the proteolytic enzyme plasmin that digests fibrin. Two forms of alpha₂AP circulate in human plasma: a 464-residue protein, which we have termed "pro"-form, or alpha₂AP_pro, and an N-terminally-shortened 452-residue "activated"-form, or alpha₂AP_act. The latter becomes crosslinked to fibrin by activated factor XIII about 5-fold more rapidly than alpha₂AP_pro and makes fibrin resistant to digestion by plasmin. A new human plasma proteinase has been identified herein that cleaves the Pro12-Asn13 bond of alpha₂AP_pro to yield alpha₂AP_act. This enzyme is identified herein as Antiplasmin Cleaving Enzyme (APCE).