Membrane alanyl aminopeptidase (EC3.4.11.2) also known as alanyl aminopeptidase (AAP) or aminopeptidase N (AP-N) is an enzyme that in humans is encoded by the ANPEP gene.
Function
Aminopeptidase N is located in the small-intestinal and renal microvillar membrane, and also in other plasma membranes. In the small intestine aminopeptidase N plays a role in the final digestion of peptides generated from hydrolysis of proteins by gastric and pancreatic proteases. Its function in proximal tubular epithelial cells and other cell types is less clear. The large extracellular carboxyterminal domain contains a pentapeptide consensus sequence characteristic of members of the zinc-binding metalloproteinase superfamily. Sequence comparisons with known enzymes of this class showed that CD13 and aminopeptidase N are identical. The latter enzyme was thought to be involved in the metabolism of regulatory peptides by diverse cell types, including small intestinal and renal tubular epithelial cells, macrophages, granulocytes, and synaptic membranes from the CNS. Defects in this gene appear to be a cause of various types of leukemia or lymphoma.[5]
Shapiro LH, Ashmun RA, Roberts WM, Look AT (June 1991). "Separate promoters control transcription of the human aminopeptidase N gene in myeloid and intestinal epithelial cells". The Journal of Biological Chemistry. 266 (18): 11999–2007. PMID1675638.
O'Connell PJ, Gerkis V, d'Apice AJ (March 1991). "Variable O-glycosylation of CD13 (aminopeptidase N)". The Journal of Biological Chemistry. 266 (7): 4593–7. PMID1705556.
Watt VM, Willard HF (October 1990). "The human aminopeptidase N gene: isolation, chromosome localization, and DNA polymorphism analysis". Human Genetics. 85 (6): 651–4. doi:10.1007/BF00193592. PMID1977688.
Tokioka-Terao M, Hiwada K, Kokubu T (1985). "Purification and characterization of aminopeptidase N from human plasma". Enzyme. 32 (2): 65–75. PMID6149934.
Watanabe Y, Iwaki-Egawa S, Mizukoshi H, Fujimoto Y (July 1995). "Identification of an alanine aminopeptidase in human maternal serum as a membrane-bound aminopeptidase N". Biological Chemistry Hoppe-Seyler. 376 (7): 397–400. doi:10.1515/bchm3.1995.376.7.397. PMID7576235.
Favaloro EJ, Browning T, Facey D (December 1993). "CD13 (GP150; aminopeptidase-N): predominant functional activity in blood is localized to plasma and is not cell-surface associated". Experimental Hematology. 21 (13): 1695–701. PMID7902291.
Norén K, Hansen GH, Clausen H, Norén O, Sjöström H, Vogel LK (February 1997). "Defectively N-glycosylated and non-O-glycosylated aminopeptidase N (CD13) is normally expressed at the cell surface and has full enzymatic activity". Experimental Cell Research. 231 (1): 112–8. doi:10.1006/excr.1996.3455. PMID9056417.