Inactivation of human plasma α1‐proteinase inhibitor by human PMN leucocyte collagenase

Abstract

Highly purified human polymorphonuelear leucocyte collagenase cleaved human α-1-proteinase inhibitor (α₁-PI) at the carboxyl site of Phe³⁵² (P₇). The inhibitor was thereby rapidly inactivated and generated a primary degradation product as shown by reverse-phase HPLC and N-terminal sequencing. Prolonged incubation of the modified inhibitor with polymorphonuclear leucocyte collagenase led to the generation of a secondary degradation product with additional cleavage at the carboxyl site of Pro³⁵⁷ (P₂).