EC - Complement subcomponent C1̅r̅

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IntEnz Enzyme Nomenclature


Accepted name:
complement subcomponent C1̅r̅
Other names:
C1̅r̅ esterase
activated complement C1r
Systematic name:



Activated from proenzyme C1̅r̅ in plasma during activation of the complement system by the "classical" route. 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:0003815
CAS Registry Number: 80295-69-8


  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. Leytus, S.P., Kurachi, K., Sakariassen, K.S. and Davie, E.W.
    Nucleotide sequence of the cDNA coding for human complement C1r.
    Biochemistry 25: 4855-4863 (1986). [PMID: 3021205]
  3. Müller-Eberhard, H.J.
    Molecular organization and function of the complement system.
    Annu. Rev. Biochem. 57: 321-347 (1988). [PMID: 3052276]

[EC created 1981]