N-acetylglutamate synthase involved in arginine biosynthesis. acetyl-CoA + L-glutamate = CoA + H(+) + N-acetyl-L-glutamate Inhibited by arginine. Optimum pH is 8.8-9. Amino-acid biosynthesis; L-arginine biosynthesis; N(2)-acetyl-L-ornithine from L-glutamate: step 1/4. By histidine or arginine limitation. Belongs to the acetyltransferase family.