Identification of a novel human UDP-GalNAc transferase with unique catalytic activity and expression profile

Biochem Biophys Res Commun. 2010 Nov 26;402(4):680-6. doi: 10.1016/j.bbrc.2010.10.084. Epub 2010 Oct 25.

Abstract

A novel member of the human ppGalNAc-T family, ppGalNAc-T20, was identified and characterized. Amino acid alignment revealed a high sequence identity between ppGalNAc-T20 and -T10. In the GalNAc transfer assay towards mucin-derived peptide substrates, the recombinant ppGalNAc-T20 demonstrated to be a typical glycopeptide GalNAc-transferase that exhibits activity towards mono-GalNAc-glycosylated peptide EA2 derived from rat submandibular gland mucin but no activity towards non-modified EA2. The in vitro catalytic property of ppGalNAc-T20 was compared with that of ppGalNAc-T10 to show different acceptor substrate specificities and kinetic constants. The ppGalNAc-T20 transcript was found exclusively in testis and brain. In situ hybridization further reveals that ppGalNAc-T20 was specifically localized in primary and secondary spermatocytes of the two meiotic periods, suggesting that it may involve in O-glycosylation during mouse spermatogenesis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Brain / enzymology*
  • Catalysis
  • Glycosylation
  • Humans
  • In Situ Hybridization
  • Male
  • Mice
  • Molecular Sequence Data
  • N-Acetylgalactosaminyltransferases / classification
  • N-Acetylgalactosaminyltransferases / genetics
  • N-Acetylgalactosaminyltransferases / metabolism*
  • Phylogeny
  • Polypeptide N-acetylgalactosaminyltransferase
  • Rats
  • Testis / enzymology*
  • Transcription, Genetic

Substances

  • N-Acetylgalactosaminyltransferases
  • ppGalNAc-T20 protein, human