Carboxypeptidases (CPs) are a type of exopeptidase that specifically degrade and release free amino acids from the C-terminus of the peptide chain one by one. In the tissues and organs of animals and plants, carboxypeptidase plays an important physiological function. For example, pancreatic carboxypeptidase A and B can be used to digest food, carboxypeptidase M (CPM) is selectively involved in the processing of peptide hormones, and carboxypeptidase D (CPD) and carboxypeptidase N (CPN) are involved in peptide and protein processing. Wait. Carboxypeptidase is widely used in medicine, food and other industrial fields. In the field of medicine, since carboxypeptidase is widely involved in the body's biochemical reactions, the detection of carboxypeptidase in the body can achieve the purpose of diagnosis and treatment of diseases. In addition, it can also be used in medicine to degrade harmful substances in the body.
Figure 1. Protein structure of Carboxypeptidases.
Classifications
- Serine carboxypeptidase
- Metallocarboxypeptidase
- Cystine carboxypeptidase
Serine carboxypeptidases (SCP), also known as acid carboxypeptidases, is a type of eukaryotic proteolytic enzymes with a relative molecular weight of 40,000-75,000 subunits, which are widely found in fungi, higher plants and animal tissues.
Metallic carboxypeptidase is a type of carboxypeptidase that exists outside the cell and helps protein digestion. It has organic activity under neutral or weak alkaline conditions. Among them, carboxypeptidase A can release C-terminal amino acids, it has strong hydrolysis ability for carboxy-terminal amino acids with aromatic side chains and large fatty side chains.
Cysteine carboxypeptidase is also known as cathepsin X (cathepsinX). It has broad-spectrum activity on C-terminal amino acids, but has no activity on C-terminal Pro, and the endonuclease activity is very weak.
Functions
Carboxypeptidase can hydrolyze the C-terminal aromatic or neutral aliphatic amino acid residues of protein and polypeptide substrates, releasing all C-terminal amino acids except proline, hydroxyproline, arginine and lysine. Easy to hydrolyze carboxy-terminal amino acids with aromatic side chains and large fatty side chains. Such as tyrosine, phenylalanine, alanine and so on.
Applications
Carboxypeptidase is widely used in medicine, food and other industrial fields. In the field of medicine. Since carboxypeptidase is widely involved in the body's biochemical reactions, the purpose of diagnosis and treatment of diseases can be achieved through the detection of carboxypeptidase in the body. In addition, it can also be used in medicine to degrade harmful substances (toxins, etc.) in the body. In the food industry, it can be used to prepare high F-value oligopeptides, to remove ochratoxin in food and feed, and as a debittering agent. In the field of biotechnology, carboxypeptidase can be used for peptide synthesis and peptide amino acid sequence determination. It can also be used as a model enzyme to help the research of other enzymes. Animal-derived carboxypeptidases are mainly found in the pancreas of pigs and cattle, such as carboxypeptidase A/B (cadxypeptidaseA/B), which are very limited in quantity and expensive, which limits their application; microbial-derived carboxypeptides enzymes exist in vacuoles of fungi such as yeast and Aspergillus, and have broad application prospects. Therefore, using genetic engineering strategies to use microorganisms as the host to mass-produce recombinant carboxypeptidase is expected to overcome the limitations of animal and plant raw material sources encountered in the production process of carboxypeptidase.
