Patent ID: 8236533

Claim:
A process for preparing a γ-glutamyl cysteine derivative comprising an α,γ-amide linkage between a cysteine moiety and a glutamic acid moiety, comprising reacting a cysteine derivative comprising a cysteine moiety, a γ-glutamyl donor comprising a γ-glutamyl moiety and an enzyme capable of transferring the γ-glutamyl moiety of the γ-glutamyl donor to the cysteine moiety of the cysteine derivative in a reaction environment that promotes transfer of the γ-glutamyl moiety to the cysteine derivative, wherein the cysteine derivative is selected from the group consisting of: a mixed disulphide of cysteine and a low molecular weight water-soluble thiol; S-acetylcysteine; an S-acetamidoalkyl derivative of cysteine; an S-alkoxycarbonylsulphenyl derivative of cysteine; S-sulphocysteine; S-ethylaminocarbonylcysteiene; and an alkyl ester of cystine, wherein the γ-glutamyl cysteine derivative is obtained.