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.
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]
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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): 1695–1701. PMID7902291.
Núñez L, Amigo L, Rigotti A, Puglielli L, Mingrone G, Greco AV, et al. (August 1993). "Cholesterol crystallization-promoting activity of aminopeptidase-N isolated from the vesicular carrier of biliary lipids". FEBS Letters. 329 (1–2): 84–88. doi:10.1016/0014-5793(93)80199-5. PMID8102610. S2CID23782523.
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): 112–118. doi:10.1006/excr.1996.3455. PMID9056417.
