CPB2 - Carboxypeptidase B2 - human protein (Function)
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CPB2 »  Carboxypeptidase B2   [ EC ]
Protein also known as:  Thrombin-activable fibrinolysis inhibitor (TAFI).
Gene name:  CPB2
Family name: Peptidase M14
Entry whose protein(s) existence is based on evidence at protein level
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Cleaves C-terminal arginine or lysine residues from biologically active peptides such as kinins or anaphylatoxins in the circulation thereby regulating their activities. Down-regulates fibrinolysis by removing C-terminal lysine residues from fibrin that has already been partially degraded by plasmin.  
  • CuratedUniProtKB
GO molecular function 
Metallocarboxypeptidase activitydefinition[GO:0004181] silver  
  • IEAInterPro 2 GO
Zinc ion bindingdefinition[GO:0008270] silver  
  • IEAInterPro 2 GO
GO biological process 
Blood coagulationdefinition[GO:0007596]  
  • IEAUniProtKB KW
Cellular response to glucose stimulusdefinition[GO:0071333] silver  
  • IEAOrtholog Compara
Fibrinolysisdefinition[GO:0042730] silver  
  • IEAOrtholog Compara
Liver regenerationdefinition[GO:0097421] silver  
  • IEAOrtholog Compara
Negative regulation of fibrinolysisdefinition[GO:0051918] silver  
  • IEAOrtholog Compara
Negative regulation of hepatocyte proliferationdefinition[GO:2000346] silver  
  • IEAOrtholog Compara
Negative regulation of plasminogen activationdefinition[GO:0010757] silver  
  • IEAOrtholog Compara
Positive regulation of extracellular matrix constituent secretiondefinition[GO:0003331] silver  
  • IEAOrtholog Compara
Proteolysisdefinition[GO:0006508] silver  
  • IEAOrtholog Compara
Response to drugdefinition[GO:0042493] silver  
  • IEAOrtholog Compara
Response to heatdefinition[GO:0009408] silver  
  • IEAOrtholog Compara
Enzymatic activity 
This protein acts as an enzyme. It is known to catalyze the following reaction
EC Release of C-terminal Arg and Lys from a polypeptide.  
  • CuratedUniProtKB
It requires the following cofactor
Binds 1 zinc ion per subunit.  
  • CuratedUniProtKB
It is regulated in the following manner
TAFI/CPB2 is unique among carboxypeptidases in that it spontaneously inactivates with a short half-life, a property that is crucial for its role in controlling blood clot lysis. The zymogen is stabilized by interactions with the activation peptide. Release of the activation peptide increases a dynamic flap mobility and in time this leads to conformational changes that disrupt the catalytic site and expose a cryptic thrombin-cleavage site present at Arg-324.  
  • CuratedUniProtKB
More information is available from:
According to KEGG, this protein belongs to the following pathways:
Complement and coagulation cascades  hsa04610+1361  
Pancreatic secretion  hsa04972+1361  
Protein digestion and absorption  hsa04974+1361  
According to Reactome, this protein belongs to the following pathway:
Metabolism of Angiotensinogen to Angiotensins  REACT_147707  


Biological process 
Blood coagulation  definition   [KW-0094]
Fibrinolysis  definition   [KW-0280]
Hemostasis  definition   [KW-0356]
Molecular function 
Carboxypeptidase  definition   [KW-0121]
Hydrolase  definition   [KW-0378]
Metalloprotease  definition   [KW-0482]
Protease  definition   [KW-0645]
Technical term 
Reference proteome  definition   [KW-1185]

Further external links

GeneWiki: Carboxypeptidase_B2
GenomeRNAi: 1361