ACV synthetase (ACVS, L-δ-(α-aminoadipoyl)-L-cysteinyl-D-valine synthetase, N-(5-amino-5-carboxypentanoyl)-L-cysteinyl-D-valine synthase, EC 6.3.2.26) is an enzyme that catalyzes the chemical reaction ACV synthetase (ACVS, L-δ-(α-aminoadipoyl)-L-cysteinyl-D-valine synthetase, N-(5-amino-5-carboxypentanoyl)-L-cysteinyl-D-valine synthase, EC 6.3.2.26) is an enzyme that catalyzes the chemical reaction The five substrates of this enzyme are ATP, L-2-aminohexanedioate, L-cysteine, L-valine, and H2O, whereas its three products are AMP, diphosphate, and N--L-cysteinyl-D-valine. ACVS is an example of a nonribosomal peptide synthetase (NRPS). It participates in penicillin and cephalosporin biosyntheses.