KEGG   ENZYME: 3.4.21.43Help
Entry
EC 3.4.21.43                Enzyme                                 

Name
classical-complement-pathway C3/C5 convertase;
C3 convertase;
C_overbar_42_;
C4b,2a;
C5 convertase;
C_overbar_423_;
C4b,2a,3b;
C42;
C5 convertase;
C423;
C4b,2a,3b;
complement C.hivin.4.hivin2;
complement C3 convertase
Class
Hydrolases;
Acting on peptide bonds (peptidases);
Serine endopeptidases
BRITE hierarchy
Reaction(IUBMB)
Selective cleavage of Arg!Ser bond in complement component C3 alpha-chain to form C3a and C3b, and Arg! bond in complement component C5 alpha-chain to form C5a and C5b
Comment
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 C_overbar_1s_. 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)
History
EC 3.4.21.43 created 1981 (EC 3.4.21.44 created 1981, incorporated 1984)
Orthology
K01332  
complement component 2
Genes
HSA: 
717(C2)
PTR: 
GGO: 
PON: 
NLE: 
MCF: 
CJC: 
MMU: 
12263(C2)
RNO: 
24231(C2)
CGE: 
HGL: 
TUP: 
CFA: 
474853(C2)
AML: 
UMR: 
FCA: 
PTG: 
BTA: 
515440(C2)
BOM: 
PHD: 
CHX: 
OAS: 
SSC: 
448981(C2)
CFR: 
BACU: 
LVE: 
ECB: 
MYB: 
MYD: 
PALE: 
MDO: 
OAA: 
GGA: 
419574(C2)
AMJ: 
PSS: 
CMY: 
ACS: 
PBI: 
XLA: 
734198(c2)
XTR: 
DRE: 
TRU: 
MZE: 
OLA: 
XMA: 
BFO: 
NVE: 
 » show all
Taxonomy
Reference
1  [PMID:7043188]
  Authors
Kerr MA.
  Title
Human factor B.
  Journal
Methods. Enzymol. 80 Pt C (1981) 102-12.
Reference
2  [PMID:3052276]
  Authors
Muller-Eberhard HJ.
  Title
Molecular organization and function of the complement system.
  Journal
Annu. Rev. Biochem. 57 (1988) 321-47.
Other DBs
ExplorEnz - The Enzyme Database: 
IUBMB Enzyme Nomenclature: 
ExPASy - ENZYME nomenclature database: 
BRENDA, the Enzyme Database: 
CAS: 
56626-15-4

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