Introductions of Carboxypeptidases
Carboxypeptidases (CPs) are a class of peptide chain exonucleases that specifically degrade and release free amino acids from the C-terminus of peptide chains one by one. In animal and plant tissues and organs, carboxypeptidases play an important physiological function. For example, pancreatic carboxypeptidases A and B are used to digest food, carboxypeptidase M (CPM) is selectively involved in the processing of peptide hormones, carboxypeptidase D (CPD) and carboxypeptidase N (CPN) are involved in peptide and protein processing, etc.
Figure 1. Structure of carboxypeptidases.
Classifications
Carboxypeptidases are classified into serine carboxypeptidases according to their active centers containing serine residues, metal ions and cysteine residues, metallo-carboxypeptidases and cysteine carboxypeptidases.
Serine carboxypeptidases (SCP), also known as acidic carboxypeptidases, are a class of eukaryotic protein hydrolases with subunit relative molecular masses of 40,000-75,000 and are widely found in fungi, higher plants and animal tissues.
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Metallo-carboxypeptidases
Metallo-carboxypeptidases are a class of carboxypeptidases which exist outside the cell and help protein digestion, and have great activity under neutral or weak alkaline conditions, including carboxypeptidase A, B, lysine carboxypeptidase. Glycine carboxypeptidase and glutamate carboxypeptidase etc.
Cysteine carboxypeptidases, also known as histone X (cathepsinX), histone Z (cathepsinZ) and acidic carboxypeptidases, are a class of enzymes consisting of Cys84, His233 and Asn254 as the active centers. Carboxypeptidases containing cysteine (Cys) in the catalytic functional domain.
Source and Distribution
According to the source classification, can be divided into animal carboxypeptidases, plant carboxypeptidases and microbial carboxypeptidases. A series of metallo-carboxypeptidases are contained in different blockages of mammals to perform the corresponding physiological functions. For example, pancreatic carboxypeptidases A and B mainly help to digest food, carboxypeptidase E selectively processes. Bioactive peptides, carboxypeptidase M is selectively involved in the processing of peptide hormones, carboxypeptidase D (in Golgi) and carboxypeptidase N (in plasma) are involved in the processing of peptides and proteins.
CPA1
Carboxypeptidase A1 is an enzyme that in humans is encoded by the CPA1 gene. Three different forms of human tryptogenic carboxypeptidase A have been isolated A1 and A2 forms are monomeric proteins with different biochemical properties. Carboxypeptidase A1 is a monomeric pancreatic exopeptidase. It is involved in zymogen inhibition.
Figure 2. Structure of carboxypeptidases A.
Functions
Carboxypeptidase A can hydrolyze C-terminal aromatic or neutral aliphatic amino acid residues of proteins and peptide substrates, releasing all C-terminal amino acids except proline, hydroxyproline, arginine and lysine, and more easily hydrolyze carboxy-terminal amino acids with aromatic side chains and large aliphatic side chains. For example, tyrosine, phenylalanine, alanine, etc. Carboxypeptidase A, CPA, is named after the first letter "A" of its substrate.
Applications
Carboxypeptidase is widely used in pharmaceuticals, food and other industrial fields. In the field of medicine. Since carboxypeptidase is widely involved in the biochemical reactions of the body, it can be used to diagnose and treat diseases through the detection of carboxypeptidase in the body, and in addition, it can be used in medicine for the degradation of undesirable substances (toxins, etc.) in the body. Carboxypeptidase is widely used in the following fields:
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Thrombin-activated CPB has a broad anti-inflammatory profile
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Potentially important drug targets
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Food industry
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Hydrolysis of ochratoxin A in food or feed products
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Biotechnology
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Model enzymes designed for use as specific inhibitors of zinc proteases
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Insulin production
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Peptide synthesis