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Complement C1r MeSH Descriptor Data 2025


MeSH Heading
Complement C1r
Tree Number(s)
D08.811.277.300.280
D12.776.124.486.274.045.280
D12.776.124.486.274.050.280
Unique ID
D015923
RDF Unique Identifier
http://id.nlm.nih.gov/mesh/D015923
Scope Note
A 80-kDa subcomponent of complement C1, existing as a SERINE PROTEASE proenzyme in the intact complement C1 complex. When COMPLEMENT C1Q is bound to antibodies, the changed tertiary structure causes autolytic activation of complement C1r which is cleaved into two chains, A (heavy) and B (light, the serine protease), connected by disulfide bonds. The activated C1r serine protease, in turn, activates COMPLEMENT C1S proenzyme by cleaving the Arg426-Ile427 bond. No fragment is released when either C1r or C1s is cleaved.
Entry Term(s)
C1r Complement
Complement 1r
Complement Component 1r
Pharm Action
Immunologic Factors
Registry Numbers
EC 3.4.21.41
Previous Indexing
Complement 1 (1979-1989)
Complement Activating Enzymes (1979-1989)
Enzyme Precursors (1979-1982)
Public MeSH Note
2006; see COMPLEMENT 1R 1990-2005
History Note
2006 (1990)
Date Established
1990/01/01
Date of Entry
1989/05/25
Revision Date
2006/07/05
Complement C1r Preferred
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