A UDP-glucose:Glycoprotein glucose-1-phosphotransferase in embryonic chicken neural retina

Academic Article


  • A subclass of cell-surface glycoproteins from embryonic chicken neural retina contains a high mannose-type oligosaccharide that terminates with glucose linked via a phosphodiester bond to penultimate mannose. This unusual oligosaccharide seems responsible for the glycoprotein attachments to the cell-surface baseplate ligatin. Using β-32PUDP-3H-glucose, we demonstrate in retinal homogenates the existence of a UDP-glucose:glyco-protein glucose-1-phosphotransferase (GIcPTase) that catalyzes the synthesis of such a linkage. Characterization of the doubly labeled product resulting from activity of the transferase reveals a family of endoglycosidase H-sensitive oligosaccharides displaying a cation-exchange profile similar to that of oligosaccharides derived from ligatin-associated proteins synthesized in vivo. Further analysis confirms that the incorporation of label is due to a terminal 3H-glucose joined via a 32P-phosphodiester linkage to carbon 6 of a penultimate mannose. We propose that GIcPTase may be a controlling enzyme for the targeting of certain newly synthesized proteins to the cell surface. © 1982.
  • Published In

  • Cell  Journal
  • Digital Object Identifier (doi)

    Author List

  • Koro LA; Marchase RB
  • Start Page

  • 739
  • End Page

  • 748
  • Volume

  • 31
  • Issue

  • 3 PART 2