EC - Complement subcomponent C1̅s̅

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IntEnz Enzyme Nomenclature


Accepted name:
complement subcomponent C1̅s̅
Other names:
C1 esterase
activated complement C1s
complement C1̅s̅
Systematic name:



Activated from proenzyme C1̅s̅ in plasma by complement subcomponent C1̅r̅. 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:0003816
CAS Registry Number: 80295-70-1


  1. Sim, R.B.
    The human complement system serine proteases C1̅r̅ and C1̅s̅ and their proenzymes.
    Methods Enzymol. 80C: 26-42 (1981). [PMID: 6281620]
  2. MacKinnon, C.M., Carter, P.E., Smyth, S.J., Dunbar, B. and Fothergill, J.E.
    Molecular cloning of cDNA for human complement component C1s. The complete amino acid sequence.
    Eur. J. Biochem. 169: 547-553 (1987). [PMID: 3500856]
  3. Müller-Eberhard, H.J.
    Molecular organization and function of the complement system.
    Annu. Rev. Biochem. 57: 321-347 (1988). [PMID: 3052276]
  4. Skoog, M.T., Mehdi, S., Wiseman, J.S. and Bey, P.
    The specificity of two proteinases that cleave adjacent to arginine, C1 esterase and acrosin, for peptide p-nitroanilide substrates.
    Biochim. Biophys. Acta 996: 89-94 (1989). [PMID: 2500154]

[EC created 1981]