biology Review Ornithine Aminotransferase, an Important Glutamate-Metabolizing Enzyme at the Crossroads of Multiple Metabolic Pathways Antonin Ginguay 1,2, Luc Cynober 1,2,*, Emmanuel Curis 3,4,5,6 and Ioannis Nicolis 3,7 1 Clinical Chemistry, Cochin Hospital, GH HUPC, AP-HP, 75014 Paris, France;
[email protected] 2 Laboratory of Biological Nutrition, EA 4466 PRETRAM, Faculté de Pharmacie, Université Paris Descartes, 75006 Paris, France 3 Laboratoire de biomathématiques, plateau iB2, Faculté de Pharmacie, Université Paris Descartes, 75006 Paris, France;
[email protected] (E.C.);
[email protected] (I.N.) 4 UMR 1144, INSERM, Université Paris Descartes, 75006 Paris, France 5 UMR 1144, Université Paris Descartes, 75006 Paris, France 6 Service de biostatistiques et d’informatique médicales, hôpital Saint-Louis, Assistance publique-hôpitaux de Paris, 75010 Paris, France 7 EA 4064 “Épidémiologie environnementale: Impact sanitaire des pollutions”, Faculté de Pharmacie, Université Paris Descartes, 75006 Paris, France * Correspondence:
[email protected]; Tel.: +33-158-411-599 Academic Editors: Arthur J.L. Cooper and Thomas M. Jeitner Received: 26 October 2016; Accepted: 24 February 2017; Published: 6 March 2017 Abstract: Ornithine δ-aminotransferase (OAT, E.C. 2.6.1.13) catalyzes the transfer of the δ-amino group from ornithine (Orn) to α-ketoglutarate (aKG), yielding glutamate-5-semialdehyde and glutamate (Glu), and vice versa. In mammals, OAT is a mitochondrial enzyme, mainly located in the liver, intestine, brain, and kidney. In general, OAT serves to form glutamate from ornithine, with the notable exception of the intestine, where citrulline (Cit) or arginine (Arg) are end products.