Acetylornithine transaminase () is an enzyme first characterised from Escherichia coli that catalyzes a reversible chemical reaction that is part of the biosynthesis of ornithine and arginine:
The two substrates of this enzyme in the forward direction shown are N(2)-acetyl-L-ornithine and α-ketoglutaric acid. Its products are N-acetyl-5-oxo-L-norvaline and L-glutamic acid. The enzyme has also been found in the genus Pseudomonas.
This enzyme is a transferase, specifically a transaminase, which transfer nitrogenous groups. The systematic name of this enzyme class is N2-acetyl-L-ornithine:2-oxoglutarate 5-aminotransferase. Other names in common use include acetylornithine delta-transaminase, ACOAT, acetylornithine 5-aminotransferase, acetylornithine aminotransferase, N-acetylornithine aminotransferase, N-acetylornithine-delta-transaminase, N2-acetylornithine 5-transaminase, N2-acetyl-L-ornithine:2-oxoglutarate aminotransferase, succinylornithine aminotransferase, and 2-N-acetyl-L-ornithine:2-oxoglutarate 5-aminotransferase. It uses pyridoxal phosphate as a cofactor.
Structural studies As of late 2007, 6 structures have been solved for this class of enzymes, with PDB accession codes , , , , , and .
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