Enzymatic synthesis of γ-glutamylglutamine, a stable glutamine analogue, by γ-glutamyltranspeptidase from Escherichia coli K-12

The optimal reaction conditions for the synthesis of gamma-glutamylglutamine using gamma-glutamyltranspeptidase from Escherichia coli were determined. The maximum yield of gamma-glutamylglutamine ( 110 mM) was obtained using 250 mM L-glutamine and 1.1 U gamma-glutamyltranspeptidase/ml at pH 10.5 and at 37 degrees C for 7 h; the conversion of glutamine to gamma-glutamylglutamine was 88%.