Use of Bacterial γ-Glutamyltranspeptidase for Enzymatic Synthesis of γ- d -Glutamyl Compounds

An enzymatic method for synthesizing various gamma-D-glutamyl compounds efficiently and stereospecifically involving bacterial gamma-glutamyltranspeptidase (EC 2.3.2.2) with D-glutamine as a gamma-glutamyl donor was developed. With D-glutamine as a gamma-glutamyl donor instead of L-glutamine in gamma-glutamyltaurine synthesis, by-products such as gamma-glutamylglutamine and gamma-glutamyl-gamma-glutamyltaurine were not synthesized and the yield of gamma-glutamyltaurine dramatically increased from 25 to 71%. It was also shown that the purification could be simplified without these gamma-glutamyl by-products. The possibility of synthesizing various gamma-D-glutamyl compounds was also shown.