Ribosomal Protein S6 Modification Like Protein B (RIMKLB)

Synthesize N-acetylaspartylglutamate (NAAG), the most abundant dipeptide present in vertebrate central nervous system (CNS), and beta-citrylglutamate, a structural analogue of NAAG present in testis and immature brain.

RIMKLA, is almost exclusively expressed in the CNS, whereas RIMKLB, which shares 65% sequence identity with RIMKLA, is expressed in CNS and testis. RIMKLA catalyzed the ATP-dependent synthesis of N-acetylaspartylglutamate from N-acetylaspartate and l-glutamate. RIMKLB catalyzed this reaction as well as the synthesis of beta-citrylglutamate. The nature of the reaction products was confirmed by mass spectrometry and NMR. RIMKLA was shown to produce stoichiometric amounts of NAAG and ADP, in agreement with its belonging to the ATP-grasp family of ligases.