title: A unique biosynthetic pathway for gangliosides exists in Xenopus laevis oocytes.
abstract: It was previously reported that monosialosylgangliopentaosyl ceramide (GalNAc-GM1b) was a major ganglioside in Xenopus laevis oocytes. Here we determined biosynthetic pathways for the ganglioside by detailed measurements of glycosyltransferase activities. CMP-NeuAc:asialo-GM1 alpha 2-3 sialyltransferase (alpha 2-3 ST) and UDP-GalNAc:GM1b beta 1-4 N-acetylgalactosaminyltransferase (beta 1-4 GalNAcT) exhibited much higher activity than CMP-NeuAc:GalNAc-GA1 alpha 2-3 ST and UDP-GalNAc:asialo-GM1 beta 1-4 GalNAcT, respectively. These observations indicated the existence of a unique biosynthetic pathway in the oocytes as follows; asialo-GM1-->GM1b-->GalNAc-GM1b.
authors.affiliation: Department of Biochemical Cell Research, Tokyo Metropolitan Institute of Medical Science, Japan.
authors.forename: K I
authors.initials: KI
authors.lastname: Hidari
authors.forename: Y
authors.initials: Y
authors.lastname: Nagai
authors.forename: Y
authors.initials: Y
authors.lastname: Sanai
mesh_terms: D000818:Animals; D002240:Carbohydrate Sequence; D005260:Female; D005732:Gangliosides / Q000096:biosynthesis*; D016695:Glycosyltransferases / Q000378:metabolism; D008969:Molecular Sequence Data; D009865:Oocytes / Q000201:enzymology / Q000378:metabolism*; D012799:Sialyltransferases / Q000378:metabolism; D014982:Xenopus laevis
chemical_list: D005732:Gangliosides; D016695:Glycosyltransferases; D012799:Sialyltransferases