aminopeptidase activity

Definition

Target type: molecularfunction

Catalysis of the hydrolysis of a single N-terminal amino acid residue from a polypeptide chain. [https://www.ebi.ac.uk/merops/about/glossary.shtml#AMINOPEPTIDASE, PMID:24157837]

Aminopeptidase activity refers to the enzymatic hydrolysis of peptide bonds at the N-terminus of a polypeptide chain. This type of activity is catalyzed by aminopeptidases, which are a diverse group of enzymes found in all living organisms. They play crucial roles in various cellular processes, including protein turnover, peptide hormone processing, and the regulation of immune responses.

The catalytic mechanism of aminopeptidases involves the formation of a covalent intermediate between the enzyme and the substrate. The active site of the enzyme typically contains a nucleophile, such as a hydroxyl or sulfhydryl group, which attacks the carbonyl carbon of the peptide bond. This results in the cleavage of the peptide bond and the release of the N-terminal amino acid.

The specificity of aminopeptidases varies widely, with some enzymes exhibiting broad specificity towards different amino acid residues at the N-terminus, while others are highly specific for particular residues. The substrate specificity is determined by the shape and chemical properties of the active site.

Aminopeptidases are important for maintaining protein homeostasis by removing N-terminal amino acids from newly synthesized or damaged proteins. This process is essential for proper protein folding and stability. Additionally, aminopeptidases play a role in the processing of peptide hormones, such as insulin and glucagon, which are essential for regulating metabolism.

Furthermore, aminopeptidases are involved in immune responses by degrading antigens, which are foreign molecules that trigger immune reactions. The breakdown of antigens by aminopeptidases reduces their immunogenicity and helps to resolve inflammation.

In conclusion, aminopeptidase activity is a fundamental enzymatic process that is essential for numerous cellular functions. The diverse group of aminopeptidases exhibits a wide range of substrate specificity and plays important roles in protein turnover, hormone processing, and immune responses.'
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Proteins (25)

Compounds (171)