Principles of the Reaction

The Synermed® γ-GT procedure utilizes a modification of the method developed by Szasz wherein γ-GT catalyzes the transfer of the g-glutamyl group from the substrate g-glutamyl-3-carboxy-4-nitroanilide to glycylglycine yielding 5-amino-2-nitrobenzoate which absorbs at 405-410 nm.

                                                                                           γ-GT
γ-glutamyl-3-carboxy-4- nitroanilide + glycylglycine -> g-glutamyl-glycylglycine + 5-amino-2-nitrobenzoate

The change in absorbance at 405-410 nm due to the formation of the 5-amino-2-nitrobenzoate is directly proportional to the γ-GT activity in the sample.