THE SACCHARIDES OF THE MUC-1 MUCIN-TYPE GLYCOPROTEIN, EPITECTIN, PRODUCED BY H.EP.2 CELLS IN THE PRESENCE OF ARYL-N-ACETYL-ALPHA-GALACTOSAMINIDES

The treatment of H.Ep.2 cells with 4 mM aryl-N-acetyl-alpha-galactosam inide, an inhibitor of the elongation of O-linked saccharides of glyco proteins, resulted in a 70-80% decrease in the incorporation of [H-3]g lucosamine into epitectin (a MUC 1 mucin-type glycoprotein), Gel elect rophoresis of the partially glycosylated epitectin immunoprecipitated from the extracts of treated cells showed two bands of apparent mel. w ts 420 and 460 kDa on SDS-PAGE, compared to bands of 350 and 390 kDa f or the native epitectin. Analysis of the saccharides released by p-eli mination from the partially glycosylated epitectin showed the presence of substantial levels of beta 1-->3 galactosylated and sialylated sac charides, The data indicate that the inhibition of elongation of Ser/T hr-linked N-acetylgalactosamine amine in epitectin by aryl-N-acetyl-al pha-galactosaminides is only partial.