Structural change of sugar chains of glycoproteins by cell transformation and its application to the diagnosis of cancer

: Comparative study by using hydrazinolysis has revealed that the carbohydrate moieties of gamma-glutamyl transpeptidases purified from rat liver and rat AH-66 hepatoma are quite different. The sugar chains of the liver enzyme were all acidic, while 29% of those of hepatoma enzyme was neutral. Three prominent structural differences were found in the acidic sugar chains of the two enzymes: 1) The liver enzyme has asparagine-linked sugar chains with complete outer chain, NeuAc alpha----Gal beta 1----4GlcNAc, while hepatoma enzyme has sugar chains incomplete in their outer chain moieties; 2) Gal beta 1----4GlcNAc beta 1----4GlcNAc group is found in the sugar chains of liver enzyme but not in those of hepatoma enzyme; 3) More than 40% of the sugar chains of hepatoma enzyme contain bisecting N-acetylglucosamine which is not found in those of liver enzyme.