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

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