INVITRO EFFECTS OF DIVALENT METAL-IONS AND METABOLIC MODULATORS ON PURIFIED GLUTAMINE-SYNTHETASE FROM BRAIN OF TELEOSTEAN FISH

The purified brain glutamine synthetase of a teleostean fish, Clarias batrachus has been examined under the influence of divalent metal ions activation and in vitro studies using different amino acids and metabolic modulators. All observations of the enzyme activity are based on transferase reaction at optimum temperature and pH. The enzyme exhibits an absolute requirement for Mn2+ (most potent) Mg2+ and Co2+. The activity is markedly inhibited by leucine, asparagine, isoleucine, carbamyl phosphate, uridine monophosphate and glutamate and activated by alpha-ketoglutarate. The significance of these results has been discussed in brief with emphasis on its involvement in teleostean physiology and metabolism.