EC 3.4.21.43 - Classical-complement-pathway C3/C5 convertase

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IntEnz Enzyme Nomenclature
EC 3.4.21.43

Names

Accepted name:
classical-complement-pathway C3/C5 convertase
Other names:
C3 convertase
C42
C423
C4b,2a
C4b,2a,3b
C5 convertase
C4̅2̅3̅
C4̅2̅
complement C3 convertase
complement C42
Systematic name:

Reaction

Comments:

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 3.4.21.44. Complement component C2a is in peptidase family S1 (trypsin family).

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , MEROPS , UniPathway
Protein domains and families: PROSITE:PDOC00124
Structural data: CSA , EC2PDB
Gene Ontology: GO:0003813
CAS Registry Number: 56626-15-4
UniProtKB/Swiss-Prot:

References

  1. Kerr, M.A.
    The second component of human complement.
    Methods Enzymol. 80C: 54-64 (1980). [PMID: 7043188]
  2. Müller-Eberhard, H.J.
    Molecular organization and function of the complement system.
    Annu. Rev. Biochem. 57: 321-347 (1988). [PMID: 3052276]

[EC 3.4.21.43 created 1981 (EC 3.4.21.44 created 1981, incorporated 1984)]