– N-Acetyl-L-glutamic acid (Ac-L-Glu-OH) (NAcGlu) is an acetylated amino acid. NAcGlu is biosynthesized from glutamic acid and acetyl-CoA by the enzyme N-acetyl glutamate synthase (NAGS). NAcGlu activates carbamoyl phosphate synthetase in the urea cycle. A deficiency in N-acetyl glutamate synthase or a genetic mutation in the gene coding for the enzyme will lead to urea cycle failure in which ammonia is not converted to urea, but rather accumulated in the blood leading to the condition called Type I hyperammonemia.