α-(2 → 3)- and α-(2 → 6)-Sialyltransferase activities present in three variants of Ehrlich tumor cells: identification of the products derived from N-acetyllactosamine and β-d-Gal-(1 → 3)-αd GalNAc-(1 → O)-Bn
✍ Scribed by Seiko Shigeta; Harry C. Winter; Irwin J. Goldstein
- Publisher
- Elsevier Science
- Year
- 1994
- Tongue
- English
- Weight
- 942 KB
- Volume
- 264
- Category
- Article
- ISSN
- 0008-6215
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✦ Synopsis
We compared several sialyltransferase activities related to synthesis of O-linked and N-linked sialylglycoproteins 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 P-D-Gal-( 1-+ 3) -D-GalNAc (w-( 2 -+ 3) -sialyltransferase activity. Sialylation of N-acetyllactosamine, lacto-N-tetraose, and benzyl W-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 &~-Gal-( 1 + 4) -D-GlcNAc mostly by (Y-( 2 + 3) -sialyltransferase, whereas &D-Gal-( 1 + 4) -D-GlcNAc (Y-( 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