Galactosyltransferase and membrane glycoprotein abnormality in human platelets from Tn-syndrome donors

Early studies on the analysis of membranes isolated from the erythrocytes of Tn-patients by SDS-polyacrylamide gel electrophoresis (SDS-PAGE) revealed a severe reduction in the staining capacity of glycophorin with the periodate-Schiff (PAS) reaction. A low sialic acid and galactose (Gal) content of the polyagglutinable red cells was confirmed while it was reported that the abnormal red cells of Tn-patients contained little or no UDPGal: GalNAc-beta-3-D-galactosyltransferase (T-transferase) activity. The glycoprotein (GP) abnormality in Tn-erythrocytes appeared to be due to incomplete synthesis of the alkali-labile oligosaccharide chaims of glycophorin. We now report studies on the membrane GP composition and the T-transferase activity of platelets isolated from there Tn-syndrome patients whose red cell membranes contain GP abnormalities which are typical of those found in this rare clinical condition.