GLYCOSYL TRANSFERASES OF MICROSOMAL FRACTIONS FROM BRAIN: SYNTHESIS OF GLUCOSYL CERAMIDE AND GALACTOSYL CERAMIDE DURING DEVELOPMENT AND THE DISTRIBUTION OF GLUCOSE AND GALACTOSE TRANSFERASE IN WHITE AND GREY MATTER1

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Abstract
Abstract— The substrate specificity for glycosyl transferases of microsomal fractions from brain was investigated. Ceramides were found to be better acceptors than sphingosine for both glucose and galactose when a Celite dispersion of lipid substrate was used. For galactose transfer only hydroxy fatty acid ceramide served as an acceptor. For transfer of glucose both non‐hydroxy and hydroxy fatty acid ceramide served as acceptors, but the hydroxy fatty acid ceramide was the more effective of the two. Glucose transferase activity was found to be highest between birth and 15 days of age and declined slowly with later development. Galactose transferase activity did not appear until the 10th day of postnatal age and reached a peak at about the 30th day. Galactose transferase activity was present principally in white matter microsomes, but glucose transferase activity was present in the microsomal fractions of both white and grey matter. The developmental alteration in the activities of galactosyl and glucosyl transferases and their distribution in white and grey matter correlated with development and distribution of cerebroside and ganglioside, respectively.