title: Sialosyltransferase activity and specificity in the biosynthesis in vitro of sialosylgalactosylceramide (GM4) and sialosyllactosylceramide (GM3) by rat astrocytes, neuronal perikarya, and oligodendroglia.
abstract: Total homogenates of astrocytes, neuronal perikarya, and oligodendroglia isolated from rat brain exhibited sialosyltransferase activity in the biosynthesis in vitro of GM3 from lac-cer and CMP-NeuNAc. This activity was highest in neuronal perikarya. In contrast, only oligodendroglia were found to be capable of catalyzing the transfer of NeuNAc from CMP-NeuNAc to gal-cer to form GM4. This activity was about three fold higher in oligodendroglia from 10-day-old rat brain than in those from 60-day-old animals; an intermediate activity was observed in oligodendroglia from 20-day-old rats. Purified preparations of myelin from 14-day-old rat cerebrum, cerebellum, and spinal cord did not show activity in the synthesis of either GM3 or GM4.
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000201:enzymology; D001921:Brain / Q000201:enzymology*; D005679:G(M3) Ganglioside / Q000096:biosynthesis*; D005732:Gangliosides / Q000096:biosynthesis*; D066298:In Vitro Techniques; D009474:Neurons / Q000201:enzymology*; D009836:Oligodendroglia / Q000201:enzymology; D051381:Rats; D012799:Sialyltransferases / Q000378:metabolism*; D014166:Transferases / Q000378:metabolism*
chemical_list: D005679:G(M3) Ganglioside; D005732:Gangliosides; C028253:ganglioside, GM4; D014166:Transferases; D012799:Sialyltransferases