Complement C1s

Synonyms

C 1 Esterase

C1 Esterase

C1s Complement

C1s, Complement

Complement 1 Esterase

Complement 1s

Complement Component 1s

Complement, C1s

Component 1s, Complement

Esterase, C 1

Esterase, C1

Esterase, Complement 1

A 77-kDa subcomponent of complement C1, encoded by gene C1S, is a SERINE PROTEASE existing as a proenzyme (homodimer) in the intact complement C1 complex. Upon the binding of COMPLEMENT C1Q to antibodies, the activated COMPLEMENT C1R cleaves C1s into two chains, A (heavy) and B (light, the serine protease), linked by disulfide bonds yielding the active C1s. The activated C1s, in turn, cleaves COMPLEMENT C2 and COMPLEMENT C4 to form C4b2a (CLASSICAL C3 CONVERTASE).