Plays a role in the regulation of ureagenesis by producing the essential cofactor N-acetylglutamate (NAG), thus modulating carbamoylphosphate synthase I (CPS1) activity. {ECO:0000269|PubMed:12459178, ECO:0000269|PubMed:23894642, ECO:0000269|PubMed:7126172}. This is the function of Ensembl gene identifier ENSG00000161653 (NAGS, N-acetylglutamate synthase).