Carcinoembryonic character of gamma-glutamyltranspeptidase in primary hepatocellular carcinoma.

As a characteristic isoenzyme of gamma-glutamyl transpeptidase (gamma-GTP) has been detected in sera of patients with primary hepatocellular carcinoma, which migrates to alpha-globulin region on polyacrylamide-gel electrophoresis, biochemical studies on human fetal liver, Morris hepatoma (7316-A, 7794-A), and human hepatoma was carried out to elucidate its carcinoembryonic character. The highest distribution of the enzyme was found in particle fraction of human fetal liver as well as of Morris hepatoma, and an isoenzyme of gamma-GTP with the same electrophoretic mobility as detected in human hepatoma was obtained, which reflected to the pattern of the serum zymograms. Histochemically, the enzyme was distributed in plasma membrane of the fetal hepatocytes and Morris hepatoma cells, while it was distributed diffusely throughout the cytoplasm of human hepatoma cells. These findings may strongly suggest that gamma-GTP in hepatoma has a carcinoembryonic character and the detection of a serum isoenzyme in the alpha-globulin region is a quite diagnostic as well as the detection of alpha-fetoprotein in the field of neoplasma of the liver. The physicochemical and kinetic properties of the enzyme in human hepatoma were also discussed.