Alanine aminopeptidase

Alanine aminopeptidase (AAP), also known as Aminopeptidase N (APN) or CD13, is an enzyme that is encoded by the ANPEP gene in humans. This enzyme is a member of the M1 family of metallopeptidases and is involved in the cleavage of N-terminal amino acids from peptides and proteins.

Function

Alanine aminopeptidase plays a crucial role in the metabolism of proteins by removing N-terminal amino acids from peptides. It is widely distributed in various tissues, including the kidney, intestine, and liver. In the kidney, it is involved in the reabsorption of peptides and amino acids. In the intestine, it aids in the digestion of dietary proteins.

Structure

The enzyme is a type II transmembrane protein with a single transmembrane domain. The active site of alanine aminopeptidase contains a zinc ion, which is essential for its catalytic activity. The enzyme is glycosylated and exists as a homodimer on the cell surface.

Clinical Significance

Alanine aminopeptidase is used as a biomarker for various diseases. Elevated levels of this enzyme in the blood can indicate renal disease, liver disease, or intestinal disorders. It is also implicated in the process of angiogenesis and is a target for cancer therapy due to its role in tumor growth and metastasis.

Related Enzymes

Alanine aminopeptidase is part of a larger family of aminopeptidases, which includes leucine aminopeptidase, methionine aminopeptidase, and prolyl aminopeptidase. These enzymes share similar functions but differ in their substrate specificities and tissue distributions.

See Also

• Aminopeptidase
• Metallopeptidase
• Protein metabolism
• Enzyme
• Biomarker