EC 184.108.40.206 - Classical-complement-pathway C3/C5 convertase
IntEnz Enzyme Nomenclature
complement C3 convertase
- Selective cleavage of Arg┼Ser bond in complement component C3 α-chain to form C3a and C3b, and Arg┼ bond in complement component C5 α-chain to form C5a and C5b.
A complex of complement fragments C4b, C2a and C2b. C2a contains the active site, C2b the site for C4b binding. C2a and C2b are formed by cleavage of proenzyme C2 by complement subcomponent C1̅s̅. Cleavage of C5 requires complement fragment C3b which binds C5 and renders it susceptible to cleavage by the C4b,2a complex. Includes former EC 220.127.116.11. Complement component C2a is in peptidase family S1 (trypsin family).
Links to other databases
The second component of human complement.Methods Enzymol. 80C: 54-64 (1980). [PMID: 7043188]
Molecular organization and function of the complement system.Annu. Rev. Biochem. 57: 321-347 (1988). [PMID: 3052276]
[EC 18.104.22.168 created 1981 (EC 22.214.171.124 created 1981, incorporated 1984)]