There are a number of different types of zinc-dependent carboxypeptidases (EC
3.4.17.-) [1,2]. All these enzymes seem to be structurally and functionally
related. The enzymes that belong to this family are listed below.
Carboxypeptidase A1 (EC 220.127.116.11), a pancreatic digestive enzyme that can
removes all C-terminal amino acids with the exception of Arg, Lys and Pro.
Carboxypeptidase A2 (EC 18.104.22.168), a pancreatic digestive enzyme with a
specificity similar to that of carboxypeptidase A1, but with a preference
for bulkier C-terminal residues.
Carboxypeptidase B (EC 22.214.171.124), also a pancreatic digestive enzyme, but
that preferentially removes C-terminal Arg and Lys.
Carboxypeptidase N (EC 126.96.36.199) (also known as arginine carboxypeptidase),
a plasma enzyme which protects the body from potent vasoactive and
inflammatory peptides containing C-terminal Arg or Lys (such as kinins or
anaphylatoxins) which are released into the circulation.
Carboxypeptidase H (EC 188.8.131.52) (also known as enkephalin convertase or
carboxypeptidase E), an enzyme located in secretory granules of pancreatic
islets, adrenal gland, pituitary and brain. This enzyme removes residual C-
terminal Arg or Lys remaining after initial endoprotease cleavage during
Carboxypeptidase M (EC 184.108.40.206), a membrane bound Arg and Lys specific
It is ideally situated to act on peptide hormones at local tissue sites
where it could control their activity before or after interaction with
specific plasma membrane receptors.
Mast cell carboxypeptidase (EC 220.127.116.11), an enzyme with a specificity
to carboxypeptidase A, but found in the secretory granules of mast cells.
Streptomyces griseus carboxypeptidase (Cpase SG) (EC 3.4.17.-) , which
combines the specificities of mammalian carboxypeptidases A and B.
Thermoactinomyces vulgaris carboxypeptidase T (EC 18.104.22.168) (CPT) ,
which also combines the specificities of carboxypeptidases A and B.
AEBP1 , a transcriptional repressor active in preadipocytes. AEBP1 seems
to regulate transcription by cleavage of other transcriptional proteins.
Yeast hypothetical protein YHR132c.
All of these enzymes bind an atom of zinc. Three conserved residues are
implicated in the binding of the zinc atom: two histidines and a glutamic acid
We have derived two signature patterns which contain these three zinc-ligands.
If a protein includes both signatures, the probability of it being a
eukaryotic zinc carboxypeptidase is 100%
These proteins belong to families M14A/M14B in the classification of
April 2006 / Pattern revised.
PROSITE methods (with tools and information) covered by this documentation:
Tan F. Chan S.J. Steiner D.F. Schilling J.W. Skidgel R.A.
Molecular cloning and sequencing of the cDNA for human membrane-bound carboxypeptidase M. Comparison with carboxypeptidases A, B, H, and N.
Hourdou M.-L. Guinand M. Vacheron M.J. Michel G. Denoroy L. Duez C.M. Englebert S. Joris B. Weber G. Ghuysen J.-M.
Characterization of the sporulation-related gamma-D-glutamyl-(L)meso-diaminopimelic-acid-hydrolysing peptidase I of Bacillus sphaericus NCTC 9602 as a member of the metallo(zinc) carboxypeptidase A family. Modular design of the protein.
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