Carboxypeptidase D can refer to one of several enzymes. A family of serine carboxypeptidases (i.e. enzymes that use an active site serine residue) includes (, ''cereal serine carboxypeptidase II'', ''Saccharomyces cerevisiae KEX1 gene product'', ''carboxypeptidase Kex1'', ''gene KEX1 serine carboxypeptidase'', ''KEX1 carboxypeptidase'', ''KEX1 proteinase'', ''KEX1DELTAp'', ''CPDW-II'', ''serine carboxypeptidase'', ''Phaseolus proteinase'') is an

enzyme An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different mol ...

. This enzyme has an optimal pH of 4.5-6.0, is inhibited by

diisopropyl fluorophosphate Diisopropyl fluorophosphate (DFP) or Isoflurophate is an oily, colorless liquid with the chemical formula C6H14FO3P. It is used in medicine and as an organophosphorus insecticide. It is stable, but undergoes hydrolysis when subjected to moisture ...

, and catalyses the following

chemical reaction A chemical reaction is a process that leads to the chemistry, chemical transformation of one set of chemical substances to another. When chemical reactions occur, the atoms are rearranged and the reaction is accompanied by an Gibbs free energy, ...

: Preferential release of a

C-terminal The C-terminus (also known as the carboxyl-terminus, carboxy-terminus, C-terminal tail, carboxy tail, C-terminal end, or COOH-terminus) is the end of an amino acid chain (protein or polypeptide), terminated by a free carboxyl group (-COOH). When t ...

arginine Arginine is the amino acid with the formula (H2N)(HN)CN(H)(CH2)3CH(NH2)CO2H. The molecule features a guanidinium, guanidino group appended to a standard amino acid framework. At physiological pH, the carboxylic acid is deprotonated (−CO2−) a ...

lysine Lysine (symbol Lys or K) is an α-amino acid that is a precursor to many proteins. Lysine contains an α-amino group (which is in the protonated form when the lysine is dissolved in water at physiological pH), an α-carboxylic acid group ( ...

residue A completely distinct enzyme has also been named carboxypeptidase D (EC number 3.4.17.22). This second enzyme is a metallocarboxypeptidase (i.e. uses a zinc ion in the active site instead of a serine residue) and is broadly expressed in mammalian tissues. Like the serine carboxypeptidase, the metallocarboxypeptidase D also removes

residues from peptides, with an optimal pH range of 5 to 7. Metallocarboxypeptidase D is located in the trans Golgi network where it contributes to the biosynthesis of neuropeptides and peptide hormones (such as insulin) along with carboxypeptidase E. In addition to this role, metallocarboxypeptidase D contributes to the processing of proteins, following the action of furin (an endoprotease located in the trans Golgi network). The duck ortholog of metallocarboxypeptidase D was named gp180 and is a receptor for the uptake of duck hepatitis B virus. In fruit fly (Drosophila melanogaster), carboxypeptidase D is known as the silver mutation, with defects causing altered wing shape. Metallocarboxypeptidase D is generally a membrane-bound protein, although in some organisms a soluble form is generated by either differential RNA splicing or by proteolytic activity. In the scientific literature, most of the published articles using the name "Carboxypeptidase D" in the title refer to metallocarboxypeptidase D and not the serine carboxypeptidase.

References

External links

* {{Portal bar, Biology, border=no EC 3.4.16