Diminished cerebroside-sulfotransferase activity in the Jimpy mouse mutant due to altered lipid composition in microsomal membranes.

The mouse mutant Jimpy shows a deficient myelination. In the microsomes of the Jimpy brain, the cerebroside-sulfotransferase (EC 2.8.2.11) activity is low. The cerebroside-sulfotransferase activity of Jimpy microsomes could be normalised by delipidating the microsomes with cold acetone and adding to them acetone-extracted lipids from normal microsomes. The lipids extracted from Jimpy membranes did not influence the cerebroside-sulfotransferase activity of neither normal nor Jimpy microsomes. The same results were obtained if artificial cholesterol-phospholipid mixtures in ratios corresponding to the ones found in normal and Jimpy membranes were used for recombination experiments. Therefore the diminished enzyme activities in Jimpy microsomes may be related to the lower cholesterol-phospholipid ratio found in the microsomal membranes of the Jimpy mutant.