Complement Component 1 Esterase Inhibitor (C1-INH)

C1-esterase inhibitor (C1-INH) is a serine protease inhibitor (serpin) that regulates the complement and contact system pathways. It inhibits activated C1r and C1s (classical pathway), MASP2 (lectin pathway), plasma kallikrein, factor XIIa (FXIIa), factor XIa (FXIa), plasmin, and tissue plasminogen activator. Deficiency or dysfunction leads to hereditary angioedema (HAE), characterized by uncontrolled bradykinin production and severe swelling. Purified human or recombinant C1-INH is used to treat/prevent HAE attacks. Polyanions such as glycosaminoglycans may act as cofactors during complex formation.

Other names

C1-r esteraseSERPING1

Irreversible inhibition of target serine proteases (C1r, C1s, MASP2, plasma kallikrein, FXIIa, FXIa, plasmin, tissue plasminogen activator) by binding to their active sites via the reactive center loop (RCL).