EC 220.127.116.11 - Complement factor I
IntEnz Enzyme Nomenclature
complement C3b inactivator
complement C3b/C4b inactivator
complement C4b inactivator
complement component C3b inactivator
conglutinogen-activating factor C
- Inactivates complement subcomponents C3b, iC3b and C4b by proteolytic cleavage.
Cleavage of complement subcomponent C3b requires its binding to cofactor factor H or complement receptor CR1; cleavage of iC3b requires complement receptor CR1; cleavage of C4b requires C4b-binding protein. In peptidase family S1 (trypsin family).
Links to other databases
Cleavage of C4b by C3b inactivator: production of a nicked form from C4b, C4b', as an intermediate cleavage product of C4b by C3b inactivator.J. Immunol. 125 : 578-582 (1980). [PMID: 7391570]
C3b inactivator and β1H.Methods Enzymol. 80C : 112-124 (1981). [PMID: 6210825]
Molecular organization and function of the complement system.Annu. Rev. Biochem. 57 : 321-347 (1988). [PMID: 3052276]
[EC 18.104.22.168 created 1981]