title: Chinese hamster ovary cells selected for resistance to the cytotoxicity of phytohemagglutinin are deficient in a UDP-N-acetylglucosamine--glycoprotein N-acetylglucosaminyltransferase activity.
abstract: Several clones of Chinese hamster ovary cells resistant to the cytotoxicity of the phytohemagglutinin from Phaseolus vulgaris show decreased binding of 125I-labeled phytohemagglutinin and contain decreased levels of a UDP-N-acetylglucosamine--glycoprotein N-acetylglucosaminyltransferase (EC 2.4.1.51; UDP-2-acetamido-2-deoxy-D-glucose:glycoprotein 2-acetamido-2-deoxy-D-glucosyltransferase) activity when compared to wild-type cells. The decrease in transferase activity varies from 45% to 96%, depending on the exogenous acceptor used in the enzyme assay. No differences between lectin-resistant and wild-type cells were noted for several other glycosyltransferases. The absence of a particular N-acetylglucosaminyltransferase in the lectin-resistant cells apparently results in defective glycosylation of lectin-binding glycoproteins on the cell surface. A phytohemagglutinin-resistant clone which shows decreased binding of 125I-labeled phytohemagglutinin but does not exhibit the enzyme deficiency has also been isolated.
mesh_terms: D001665:Binding Sites; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured / Q000187:drug effects / Q000201:enzymology* / Q000378:metabolism; D005964:Glucosyltransferases / Q000172:deficiency* / Q000378:metabolism; D007700:Kinetics; D037102:Lectins / Q000494:pharmacology; D009154:Mutation
chemical_list: D037102:Lectins; D005964:Glucosyltransferases