Description

Other Name: Complement C1s subcomponent (EC 3.4.21.42;C1 esterase;Complement component 1 subcomponent s) [Cleaved into: Complement C1s subcomponent heavy chain; Complement C1s subcomponent light chain]

Background: catalytic activity:Cleavage of Arg-|-Ala bond in complement component C4 to form C4a and C4b, and Lys(or Arg)-|-Lys bond in complement component C2 to form C2a and C2b: the ‘classical’ pathway C3 convertase.,disease:Defects in C1S are the cause of selective C1s deficiency [MIM:120580]; that is associated with early onset multiple autoimmune diseases.,enzyme regulation:Inhibited by SERPING1.,function:C1s B chain is a serine protease that combines with C1q and C1s to form C1, the first component of the classical pathway of the complement system. C1r activates C1s so that it can, in turn, activate C2 and C4.,online information:C1S mutation db,PTM:The iron and 2-oxoglutarate dependent 3-hydroxylation of aspartate and asparagine is (R) stereospecific within EGF domains.,similarity:Belongs to the peptidase S1 family.,similarity:Contains 1 EGF-like domain.,similarity:Contains 1 peptidase S1 domain.,similarity:Contains 2 CUB domains.,similarity:Contains 2 Sushi (CCP/SCR) domains.,subunit:C1 is a calcium-dependent trimolecular complex of C1q, C1r and C1s in the molar ration of 1:2:2. Activated C1s is an disulfide-linked heterodimer of a heavy chain and a light chain.,