Tyrosylprotein sulfotransferase activity is increased in human gastric mucosa of alcoholics.

Abstract

Sulfation plays a major role in the processing of secretory proteins. We report here on tyrosylprotein sulfotransferase activity in human gastric mucosa of normal and alcoholics. The tyrosylprotein sulfotransferase was identified in the Golgi-enriched fraction. In alcoholics, the activity of sulfotransferase was 2- to 3-fold higher than in normals. However, no change in the activity of UDP-glucose-ceramide glucosyltransferase, a marker for Golgi, between alcoholics and normals was observed. The tyrosylprotein sulfotransferase enzyme required Triton X-100, MnCl2 and 5'-AMP, and obtained optimum activity at pH 6.8 in the presence of 0.5% Triton X-100, 20 mM MnCl2, 50 mM NaF, and 2 mM 5'-AMP. The apparent Km for poly-Glu6, Ala3, Tyr1 (EAY; 47,000) was 1.9 x 10(-6) M and for 3'-phosphoadenosine 5'-phosphosulfate (PAPS), 1.4 x 10(-6) M. The results suggest that alcohol abuse causes enhancement in the expression of gastric mucosal tyrosylprotein sulfotransferase activity.