A novel human UDP-N-acetyl-D-galactosamine:polypeptide N-acetylgalactosaminyltransferase, GalNAc-T7, with specificity for partial GalNAc-glycosylated acceptor substrates.
A novel member of the human UDP-N-acetyl-D-galactosamine:polypeptide N-acetylgalactosaminyltransferase gene family, designated GalNAc-T7, was cloned and expressed. GalNAc-T7 exhibited different properties compared to other characterized members of this gene family, in showing apparent exclusive specificity for partially GalNAc-glycosylated acceptor substrates. GalNAc-T7 showed no activity with a large panel of non-glycosylated peptides, but was selectively activated by partial GalNAc glycosylation of peptide substrates derived from the tandem repeats of human MUC2 and rat submaxillary gland mucin. The function of GalNAc-T7 is suggested to be as a follow-up enzyme in the initiation step of O-glycosylation.
Bennett
E P
EP
Faculty of Health Sciences, School of Dentistry, Norre Alle 20, DK-2200 Copenhagen N, Denmark.
Hassan
H
H
Hollingsworth
M A
MA
Clausen
H
H
D000595:Amino Acid Sequence; D000818:Animals; D015152:Blotting, Northern; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000378:metabolism; D006031:Glycosylation; D006801:Humans; D007527:Isoenzymes; D007700:Kinetics; D008969:Molecular Sequence Data; D017350:N-Acetylgalactosaminyltransferases / Q000302:isolation & purification / Q000378:metabolism*; D010455:Peptides / Q000737:chemistry / Q000378:metabolism*; D051381:Rats; D011994:Recombinant Proteins / Q000302:isolation & purification / Q000378:metabolism; D013379:Substrate Specificity; D014018:Tissue Distribution; D014530:Uridine Diphosphate / Q000737:chemistry / Q000378:metabolism*
D018076:DNA, Complementary; D007527:Isoenzymes; D010455:Peptides; D011994:Recombinant Proteins; D014530:Uridine Diphosphate; D017350:N-Acetylgalactosaminyltransferases; C400542:UDP-N-acetylgalactosamine--polypeptide N-acetylgalactosaminyltransferase 7