Comparison of Electrophoretic and Immunological Properties of Gamma-Glutamyl Transpeptidase from Human Adult Liver, Fetal Liver and Primary Hepatoma

Abstract

γ-Glutamyl transpeptidase (γ-GT) from human fetal liver, normal adult liver and primary hepatoma was separated into a hydrophobic form (detergent-solubilized, native enzyme) and a hydrophilic form (papain-digested enzyme) using papain digestion and phenyl Sepharose CL-4B hydrophobic chromatography. On polyacrylamide slab gel electrophoresis the hydrophobic form of the enzyme from the above three sources did not enter the gel, whereas the hydrophilic form entered the gel and moved as a single band with identical mobility. Neuraminidase treatment decreased the mobilities of hydrophilic form of γ-GT from all the three sources to a similar extent suggesting that the enzymes were sialylated equally. The enzyme activities from all the three sources were inhibited and precipitated equally by antibody to fetal liver γ-GT. In Ouchterlony double diffusion test the precipitin lines formed between enzymes from the three sources and anti-fetal liver γ-GT showed a reaction of complete identity. The activity of the hydrophilic form of the enzyme was more inhibited and required less amount of antibody for precipitation compared to their hydrophobic forms of the enzyme from all the three sources.