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polypeptide N-acetylgalactosaminyltransferase 13 (protein-UDP acetylgalactosaminyltransferase 13, UDP-GalNAc:polypeptide N-acetylgalactosaminyltransferase 13, polypeptide GalNAc transferase 13, GalNAc-T13, pp-GaNTase 13, GALNT13, KIAA1918)

Function: 1) catalyzes the initial reaction in O-linked oligosaccharide biosynthesis, transfer of an N-acetyl-D-galactosamine to Ser or Thr on the nascent glycoprotein 2) much stronger activity than GALNT1 to transfer GalNAc to mucin peptides, including Muc5Ac & Muc7 3) glycosylates SDC3 4) synthesis of Tn antigen in neuronal cells (putative) UDP-N-acetyl-D-galactosamine + polypeptide UDP + N-acetyl-D-galactosaminyl-polypeptide Cofactor: Mn+2, Ca+2 Structure: - contains 1 ricin B-type lectin domain - domain binds to GalNAc & contributes to the glycopeptide specificity - conserved domains in the glycosyltransferase region - N-terminal domain (domain A, GT1 motif), role in Mn+2 coordination & substrate binding - C-terminal domain (domain B, Gal/GalNAc-T motif), role in catalytic reaction & UDP-Gal binding Compartment: Golgi apparatus membrane Alternative splicing: named isoforms=2 Expression: - expressed in neuronal cells - expressed in fetal brain, whole adult brain, cerebral cortex, cerebellum - not expressed in other tissues

General

glycoprotein membrane protein polypeptide N-acetylgalactosaminyltransferase (protein-UDP acetylgalactosaminyltransferase, UDP-GalNAc:polypeptide N-acetylgalactosaminyltransferase, polypeptide GalNAc transferase, GalNAc-T, pp-GaNTase, GALNT)

Properties

SIZE: MW = 64 kD entity length = 556 aa COMPARTMENT: golgi MOTIF: transmembrane domain {5-27} N-glycosylation site {N94} active site SITE: 114-224 MOTIF: N-glycosylation site {N116} active site SITE: 284-346 Ricin B-type lectin {428-550} MOTIF: cysteine residue {C441} MODIFICATION: cysteine residue {C458} cysteine residue {C458} MODIFICATION: cysteine residue {C441} cysteine residue {C481} MODIFICATION: cysteine residue {C496} cysteine residue {C496} MODIFICATION: cysteine residue {C481} cysteine residue {C522} MODIFICATION: cysteine residue {C539} cysteine residue {C539} MODIFICATION: cysteine residue {C522} N-glycosylation site {N551}

Database Correlations

OMIM 608369 UniProt Q8IUC8 ENZYME 2.4.1.41

References

  1. UniProt :accession Q8IUC8
  2. GGDB, GlycoGene database http://ggdb.muse.aist.go.jp/GGDB/index.jsp