Cyanophycin synthase (L-arginine-adding)

Cyanophycin synthase (L-arginine-adding) (EC 6.3.2.30, CphA, CphA1, CphA2, cyanophycin synthetase, multi-L-arginyl-poly-L-aspartate synthase) is an enzyme with systematic name cyanophycin:L-arginine ligase (ADP-forming). This enzyme catalyses the following chemical reaction:

ATP + [L-Asp(4-L-Arg)]_n-L-Asp + L-Arg ${\displaystyle \rightleftharpoons }$ ADP + phosphate + [L-Asp(4-L-Arg)]_{n + 1}

This enzyme requires Mg²⁺ for activity. This enzyme requires Mg²⁺ for activity. All enzymes known to have this activity also catalyze the addition of aspartate, i.e. cyanophycin synthase (L-aspartate-adding) activity. It is structurally similar to Muramyl ligases.