Acetylornithine transaminase

In enzymology, an acetylornithine transaminase (EC 2.6.1.11) is an enzyme that catalyzes the chemical reaction

N₂-acetyl-L-ornithine + 2-oxoglutarate <math>\rightleftharpoons</math> N-acetyl-L-glutamate 5-semialdehyde + L-glutamate

Thus, the two substrates of this enzyme are N2-acetyl-L-ornithine and 2-oxoglutarate, whereas its two products are N-acetyl-L-glutamate 5-semialdehyde and L-glutamate.

This enzyme belongs to the family of transferases, specifically the transaminases, 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. This enzyme participates in urea cycle and metabolism of amino groups. It employs one cofactor, pyridoxal phosphate.

Structural studies

As of late 2007, 6 structures have been solved for this class of enzymes, with PDB accession codes 1VEF, 1WKG, 1WKH, 2E54, 2EH6, and 2ORD.

References

IUBMB entry for 2.6.1.11
BRENDA references for 2.6.1.11 (Recommended.)
PubMed references for 2.6.1.11
PubMed Central references for 2.6.1.11
Google Scholar references for 2.6.1.11
ALBRECHT AM, VOGEL HJ (1964). "ACETYLORNITHINE DELTA-TRANSAMINASE. PARTIAL PURIFICATION AND REPRESSION BEHAVIOR". J. Biol. Chem. 239: 1872–6. PMID 14213368.
Vogel HJ (1953). "Path of Ornithine Synthesis in Escherichia Coli". Proc. Natl. Acad. Sci. U. S. A. 39: 578–83. PMID 16589307.
Voellmy R, Leisinger T (1975). "Dual role for N-2-acetylornithine 5-aminotransferase from Pseudomonas aeruginosa in arginine biosynthesis and arginine catabolism". J. Bacteriol. 122: 799–809. PMID 238949.