Alpha-(2-->3)- and alpha-(2-->6)-sialyltransferase activities present in three variants of Ehrlich tumor cells: identification of the products derived from N-acetyllactosamine and beta-D-Gal-(1-->3)-alpha-D-GalNAc-(1-->O)-Bn.
We compared several sialytransferase activities related to synthesis of O-linked and N-linked sialyglycoproteins in Ehrlich ascites tumor cells that grow normally in murine ascites, but are not adherent nor grow in tissue culture (na-EAT cells), with those in cells that were selected to grow in tissue culture and adhere to extracellular matrices (a-EAT cells). Crude Golgi preparations from both cell types contained predominantly beta-D-Gal-(1-->3)-D-GalNAc alpha-(2-->3)-sialyltransferase activity. Sialylation of N-acetyllactosamine, lacto-N-tetraose, and benzyl alpha-D-GalNAc occurred at from 1 to 4% of that activity. Analysis, by ion-exchange HPLC at high pH, of sialylated N-acetyllactosamine showed that na-EAT cells sialylated beta-D-Gal-(1-->4)-D-GlcNAc mostly by alpha-(2-->3)-sialyltransferase, whereas beta-D-Gal-(1-->4)-D-GlcNAc alpha-(2-->6)-sialyltransferase activity was prominent in a-EAT cells. In addition, preparations from na-EAT cells formed significant quantities of an unknown tritiated product from CMP-[9-3H]sialic acid, suggesting at least one other difference in enzyme levels between the cell types. a-EAT cells reestablished in murine ascites for 11 passages retained the sialyltransferase levels characteristic of a-EAT cells. When viable cells were labeled with D-[3H]glucosamine, na-EAT cells formed larger amounts of sialic acid in O-linked glycoproteins than did a-EAT cells.
Shigeta
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Department of Biochemistry, University of Michigan Medical School, Ann Arbor 48109-0606.
Winter
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Goldstein
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D000606:Amino Sugars / Q000378:metabolism*; D000818:Animals; D002240:Carbohydrate Sequence; D002286:Carcinoma, Ehrlich Tumor / Q000201:enzymology* / Q000235:genetics; D002851:Chromatography, High Pressure Liquid; D004187:Disaccharides / Q000378:metabolism*; D005260:Female; D005944:Glucosamine / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D012799:Sialyltransferases / Q000378:metabolism*; D013379:Substrate Specificity; D000094802:beta-D-Galactoside alpha 2-6-Sialyltransferase; D000094663:beta-Galactoside alpha-2,3-Sialyltransferase
D000606:Amino Sugars; D004187:Disaccharides; C090985:benzyl 2-acetamido-2-deoxy-3-O-galactopyranosylgalactopyranoside; C000458:N-acetyllactosamine; D012799:Sialyltransferases; D005944:Glucosamine; D000094802:beta-D-Galactoside alpha 2-6-Sialyltransferase; D000094663:beta-Galactoside alpha-2,3-Sialyltransferase