Determination of γ-glutamyl transpeptidase activity in human serum and urine

Abstract A simple and improved method for the synthesis of γ- l -glutamyl-α- and β-naphthylamide is described. A procedure for the determination of γ-glutamyl transpeptidase activity based on the colorimetric determination of α-naphthylamine liberated from its γ-glutamyl derivative is given.