Human Carboxypeptidase B2/CPB2 Antibody

CPB2 (Carboxypeptidase B2; also CPU and TAFI) is a secreted, 50-60 kDa glycoprotein member of the peptidase M14 family of enzymes.  It is expressed by hepatocytes (60 kDa) and platelets (50 kDa), with MW differences attributable to glycosylation.  CPB2 is cleaved by thrombin and plasmin, generating a 36 kDa, relatively insoluble nonglycosylated enzymatically active fragment (TAFIa).  Active CPB2 removes C-terminal Lys residues from fibrin, thereby interrupting plasmin generation and promoting fibrin polymerization.  Human CPB2 (proprecursor/zymogen) is 401 amino acids (aa) in length.  It contains a prosequence (aa 23-114) and an active fragment (aa 115-423) that acts on C-terminal Lys or Arg residues.  There is one potential isoform variant that shows a deletion of aa 198-234 accompanied by a 16 aa substitution for aa 382-423.  Over aa 23-423, human CPB2 shares 85% aa identity with mouse CPB2.