ISSN:
0730-2312
Keywords:
glycosyltransferase
;
cell surface
;
transformation
;
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
Notes:
Recent studies have desmonstrated that Rous sarcoma virus-transformed baby hamster kidney (RS-BHK) cells express twofold higher levels of those N-linked oligosac-charides that contain the sequence [GlcNAc-β(1,6)Man (1,6)] compared to nontrans-formed parental BHK cells (Pierce and Arango, J. Biol. Chem. 261, 10772 [1986]). We have investigated in RS-BHK and BHK cells the activity of UDP-GlcNAc:α-D-mannoside β(l,6)N-acetylglucosaminyltransferase V, the enzyme that begins the synthesis of the sequence that is increased in the RS-BHK cells. We have measured GnT V activity using UDP- [3H]- GlcNAc and a synthetic oligosaccharide acceptor, GlcNAcβ(1,2)Man α(1,6)Manβ-O- (Ch2)8COOCH3, separating the radioactive product by a newly devised reverse-phase chromatographic technique. Assayed under optimal conditions, the specific activity of GnT V is about fourfold higher in RS-BHK sonicates than in BHK sonicates, suggesting that this increase in activity may be the primary mechanism that causes the increase in [GlcNAcβ(1,6) Man] sequences in the RS-BHK cells. The apparent Km, values of the enzymes in RS-BHK and BHK cell sonicates for UDP-GIcNAc and the synthetic acceptor are similar, as are the pH optima. These results suggest that the increase in GnT V-specific activity in RS-BHK cells is not caused by the presence in these cells of a GnT V with markedly different kinetic properties.
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jcb.240370209
