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UDP-galactose:globotriaosylceramide alpha-galactosyltransferase activity in rat pheochromocytoma (PC12h) cells.

Authors: Pal, S  Saito, M  Ariga, T  Yu, R K 
Citation: Pal S, etal., J Lipid Res. 1992 Mar;33(3):411-7.
Pubmed: (View Article at PubMed) PMID:1569388

The activity of alpha-galactosyltransferase in cultured rat pheochromocytoma subcloned (PC12h) cells was examined using Gb3 as the acceptor for the galactose from UDP-galactose. The major reaction product was identified as gal alpha 1-3Gb3 based on its mobility on thin-layer chromatographic (TLC) plates and susceptibility to specific galactosidases. The enzyme activity in PC12h cells was the highest at pH 7.0 while the presence of Triton CF-54 (0.1%) and Mn2+ (5 mM) was required for its full activity. The apparent Km values for Gb3 and UDP-galactose were 57 and 17 microM, respectively. The enzyme activity in PC12h cells was compared with that in parent PC12 cells, in which gal alpha 1-3Gb3 is not expressed in an appreciable amount. In the enzyme reaction with exogenous Gb3, the enzyme activity in PC12h cells was about 1.5-fold higher than that in PC12 cells. In the absence of exogenous Gb3, this difference became even more pronounced; gal alpha 1-3Gb3 was generated from endogenous Gb3 at a much higher rate in PC12h cells than in PC12 cells. These findings suggest that the higher level of the alpha-galactosyltransferase activity in PC12h cells may, at least in part, be responsible for the accumulation of unique neutral glycosphingolipids having gal alpha 1-3 terminal residues in the cells.

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CRRD Object Information
CRRD ID: 13831122
Created: 2018-12-14
Species: All species
Last Modified: 2018-12-14
Status: ACTIVE



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