Cerebroside Sulfotransferase in Golgi‐Enriched Fractions from Rat Brain

Abstract

Golgi-enriched fractions were prepared from brainstems of 17 day old rats by first floating off myelin, then fractionating the remaining pellet by a series of differential and density gradient centrifugations in sucrose. Fractions enriched in Golgi membranes were recovered at 0.46/0.76 M and 0.76/0.87 M interfaces on the final sucrose gradient as indicated by morphology and the biochemical markers thiamine pyrophosphatase and [3H]fucose-labeled glycoprotein. Morphology of the 2 fractions indicated very little contamination with myelin lamellae. The presence of significant levels of 2'',3''-cyclic nucleotidase in the lighter fraction suggested a contribution from oligodendroglial or myelin-related membranes. Cerebroside sulfotransferase was highly enriched in the lighter Golgi-enriched fraction relative to the denser fraction, the post-34,880 .times. g microsomes, and the myelin-like fraction. Ceramide galactosyl transferase was more evenly distributed among the fractions. There was a more highly localized distribution of sulfatide synthesis than of galactocerebroside synthesis, probably in Golgi membranes or oligodendroglia-related membranes with similar properties.