Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.4.99.7 (sialyltransferase)
 1,534 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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.
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PMID: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. 800 Oct 13

Ehrlich ascites tumor cells (EAT cells) are routinely grown in the peritoneal cavity of mice. These cells, EAT-wt, grow in suspension and exhibit a high level of alpha-2,3-O-linked sialyltransferase activity with benzyl-T-antigen (Gal beta 1,3Ga1NAc-alpha-O-CH2C6H5) as acceptor. These cells also contain a very low level of alpha-2,6-O-linked and alpha-2,6-N-linked sialyltransferase activity. A variant of these cells, EAT-c, has been selected to grow in cell culture, attached to the surface of culture flasks. EAT-c cells exhibit a selective increase of two- to fivefold in the activity of alpha-2,6-N-linked sialyltransferase activity, using asialo-alpha 1-acid glycoprotein as acceptor. Since a similar selective increase has been previously observed in metastatic human colorectal cancer tissues, the EAT-wt/EAT-c cell system may serve as a good experimental model for the investigation of sialyltransferases and their cell surface sialylated products in relation to cancer, metastasis, and cell-cell interaction.
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PMID:Cultured Ehrlich ascites tumor cells show increased N-linked alpha 2,6-sialyltransferase activity. 851 12