Localization of neutral N-linked carbohydrate chains in pig zona pellucida glycoprotein ZPC

Eur J Biochem. 1999 Feb;260(1):57-63. doi: 10.1046/j.1432-1327.1999.00095.x.


Zona pellucida, a transparent envelope surrounding the mammalian oocyte, plays important roles in fertilization and consists of three glycoproteins; ZPA, ZPB and ZPC. In pig, neutral complex-type N-linked chains obtained from a ZPB/ZPC mixture possess sperm-binding activity. We have recently reported that among neutral N-linked chains triantennary and tetraantennary chains have a sperm-binding activity stronger than that of diantennary chains. Triantennary and tetraantennary chains are localized at the second of the three N-glycosylation sites of ZPB. In this study, we focused on the localization of neutral N-linked chains in ZPC. ZPB and ZPC can not be separated from each other unless the acidic N-acetyllactosamine regions of their carbohydrate chains are removed by endo-beta-galactosidase digestion. A large part of the acidic N-linked chains becomes neutral by the digestion, but the main neutral N-linked chains are not susceptible to the enzyme. N-glycanase digestion indicated that ZPC has three N-glycosylation sites. Three glycopeptides each containing one of the N-glycosylation sites were obtained by tryptic digestion of ZPC and the N-glycosylation sites were revealed as Asn124, Asn146 and Asn271. The carbohydrate structures of the neutral N-linked chains from each glycopeptide were characterized by two-dimensional sugar mapping analysis taking into consideration the structures of the main, intact neutral N-linked chains of ZPB/ZPC mixture reported previously. Triantennary and tetraantennary chains were found mainly at Asn271 of ZPC, whereas diantennary chains were present at all three N-glycosylation sites. Thus, ZPC has tri-antennary and tetra-antennary chains as well as ZPB, but the localization of the chains is different from that in ZPB.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amidohydrolases / metabolism
  • Animals
  • Carbohydrate Sequence
  • Egg Proteins / chemistry*
  • Female
  • Glycopeptides / chemistry
  • Glycoside Hydrolases*
  • Glycosylation
  • Membrane Glycoproteins / chemistry*
  • Molecular Sequence Data
  • Oligosaccharides / chemistry
  • Oocytes / chemistry
  • Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase
  • Receptors, Cell Surface*
  • Swine
  • Trypsin / metabolism
  • Zona Pellucida / chemistry*
  • Zona Pellucida Glycoproteins
  • beta-Galactosidase / metabolism


  • Egg Proteins
  • Glycopeptides
  • Membrane Glycoproteins
  • Oligosaccharides
  • Receptors, Cell Surface
  • Zona Pellucida Glycoproteins
  • Glycoside Hydrolases
  • keratan-sulfate endo-1,4-beta-galactosidase
  • beta-Galactosidase
  • Trypsin
  • Amidohydrolases
  • Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase