Identification of a novel human UDP-GalNAc transferase with unique catalytic activity and expression profile.
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.
Peng
Can
C
Ministry of Education Key Laboratory of Systems Biomedicine, Shanghai Center for Systems Biomedicine (SCSB), Shanghai Jiao Tong University, Shanghai, China.
Togayachi
Akira
A
Kwon
Yeon-Dae
YD
Xie
Chunyan
C
Wu
Gongdong
G
Zou
Xia
X
Sato
Takashi
T
Ito
Hiromi
H
Tachibana
Kouichi
K
Kubota
Tomomi
T
Noce
Toshiaki
T
Narimatsu
Hisashi
H
Zhang
Yan
Y
D000595:Amino Acid Sequence; D000818:Animals; D001921:Brain / Q000201:enzymology*; D002384:Catalysis; D006031:Glycosylation; D006801:Humans; D017403:In Situ Hybridization; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D017350:N-Acetylgalactosaminyltransferases / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D010802:Phylogeny; D051381:Rats; D013737:Testis / Q000201:enzymology*; D014158:Transcription, Genetic; D000097763:Polypeptide N-acetylgalactosaminyltransferase
D017350:N-Acetylgalactosaminyltransferases; D000097763:Polypeptide N-acetylgalactosaminyltransferase; C554949:ppGalNAc-T20 protein, human