Recombinant Production of Arginyl Dipeptides by l-Amino Acid Ligase RizA Coupled with ATP Regeneration

Arginyl dipeptides like Arg-Ser, Arg-Ala, and Arg-Gly are salt-taste enhancers can potentially be used to reduce the salt content of food. The l-amino acid ligase RizA from B. subtilis selectively synthesizes arginyl dipeptides. However, industrial application is prevented by high cost cofactor adenosine triphosphate (ATP). Thus, a coupled reaction system was created consisting acetate kinase (AckA) E. coli providing ATP regeneration acetyl phosphate. Both enzymes were recombinantly produced in purified affinity chromatography. Biocatalytic reactions varied analyzed RP-HPLC with fluorescence detection. Under optimal conditions up 5.9 g/L Arg-Ser corresponding an efficiency 23 g per gram ATP. Using similar alanine or glycine as second amino acid, 2.6 Arg-Ala 2.4 Arg Gly produced. RizA/AckA substantial amounts while minimizing usage expensive