GAMMA-GLUTAMYL TRANSFER-REACTIONS BY GLUTAMINASE FROM PSEUDOMONAS-NITROREDUCENS IFO12694 AND THEIR APPLICATION FOR THE SYNTHESES OF THEANINE AND GAMMA-GLUTAMYLMETHYLAMIDE

In a mixture containing gamma-glutamyl donor (donor) and gamma-glutamy l acceptor (acceptor), the glutaminase of Pseudomonas nitroreducens IF O 12694 simultaneously catalyzed a gamma-glutamyl transfer reaction an d hydrolysis of the donor. The variation of the activities responding to the concentration of glutathione and glycylglycine indicated that t he enzyme might be classified in a group of glutaminases that shows hy drolysis prior to transfer reaction. On the other hand, the results wi th glutamine and ethylamine or methylamine indicated that the enzyme w as active in the transfer reaction with suppressed hydrolysis of gluta mine, and suggested the possibility of using the reaction for producin g gamma-glutamylethylamide (theanine) or gamma-glutamylmethylamide (ga mma-GMA). In fact, in a mixture containing high concentrations of subs trates (0.7 M glutamine, 1.5 M ethylamine or methylamine) and 0.5 unit /ml glutaminase (borate buffer pH 11), 270 mM (47 g/L) theanine or 250 mM (38 g/L) gamma-GMA was formed in 7 h of incubation at 30 degrees C .