A method for the colorimetric determination of gamma-glutamyl transpeptidase in human serum; enzymatic activity in health and disease.

Abstract

Summary A colorimetric method for the assay of γ-glutamyl transpeptidase activity in serum and serous fluids using a synthetic substrate, N-(dl-γ-glutamyl) aniline, is described. The method is based upon the measurement of aniline liberated by the enzymatic cleavage of the substrate. The kinetics of the transfer reaction catalyzed by human serum are described. Serum transpeptidase activity was assayed in 400 normal subjects and 545 patients with cancer and other diseases not involving the hepatobiliary tract or pancreas. The upper limits of normal were 120 units for men and 65 units for women. Most of the patients had normal serum levels and the remainder had elevations that did not exceed 500 units.