STUDIES ON BIOSYNTHESIS OF GASTRIC MUCOSAL GLYCOPROTEIN IN GASTRIC DISEASES

I: Basic studies on UDP-galactosyl transferase in human gastric mucosa

Abstract

For porpuse of studying the biosynthesis of gastric mucosal glycoprotein, which has a role as gastric mucosal defensive factor, the assay method for UDP-galactosyl transferase was studied, and some characteristics of UDP-galactosyl transferase were studied. The assay required Mn⁺⁺, Triton X-100, and asialo-agalacto-fetuin at condition pH 7.5. When endogenous acceptor was used, only 3.2% of [³H] galactose were incorporated comparing to the standard assay. The gastric mucosa could be stored at -15°C, for 8 weeks without loss of UDP-galactosyl transferase activity. This enzyme localyzed in microsomal fraction of gastric mucosa. When the reaction product was applied to a column of Sephadex G-100, [³H] galactose was eluted in the fraction of acceptor protein and 81% of [³H] galactose were liberated with β-galactosidase.