title: The biosynthesis of gangliosides. The incorporation of galactose, N-acetylgalactosamine and N-acetylneuraminic acid into endogenous acceptors of subcellular particles from rat brain in vitro.
abstract: Gangliosides bound to subcellular particles from rat brain were labelled by incubation of the particles (i) with CMP-N[(3)H]-acetylneuraminic acid and (ii) simultaneously, with CMP-N[(3)H]-acetylneuraminic acid and UDP-N-acetyl-[(14)C(1)]galactosamine or with CMP-N[(3)H]-acetylneuraminic acid and UDP-[U-(14)C]-galactose. Analysis of the labelled gangliosides showed that in (i), (a) the labelling was mostly in the neuraminidase-labile sialyl groups, (b) rigid relationships exist between the enzymes and the sialyl acceptors; the enzymes are not free to interact with all the specific substrates present in the preparation and (c) the precursor of the trisialoganglioside was the major disialoganglioside with a sialyl 2-->8 sialyl group. In (ii), (a) precursor-product relationships between the main pools of each ganglioside apparently do not exist, (b) for the labelling of Tay-Sachs ganglioside the amount formed from hematoside was at least 2.5 times that from aminoglycolipid and (c) the major monosialoganglioside was the precursor for the major disialoganglioside with a sialyl 2-->8 sialyl group.
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism*; D002247:Carbon Isotopes; D002498:Centrifugation; D003956:Dialysis; D005688:Galactosamine / Q000378:metabolism; D005690:Galactose / Q000378:metabolism*; D005732:Gangliosides / Q000032:analysis / Q000096:biosynthesis*; D006017:Glycolipids / Q000378:metabolism; D006595:Hexosamines / Q000378:metabolism*; D066298:In Vitro Techniques; D007700:Kinetics; D009438:Neuraminic Acids / Q000378:metabolism*; D009439:Neuraminidase; D051381:Rats; D014316:Tritium
chemical_list: D002247:Carbon Isotopes; D005732:Gangliosides; D006017:Glycolipids; D006595:Hexosamines; D009438:Neuraminic Acids; D014316:Tritium; D005688:Galactosamine; D009439:Neuraminidase; D005690:Galactose