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sialyltransferase 4A; CMP-N-acetylneuraminate-beta-galactosamide-alpha-2,3-sialyltransferase; beta-galactoside alpha-2,3-sialyltransferase; alpha 2,3-ST; Gal-NAC6S; Gal-beta-1,3-GalNAc-alpha-2,3-sialyltransferase; ST3GALIA; ST3O; ST3GALA.1 (SIAT4A, ST3GAL1)
Function:
- may be responsible for the synthesis of the sequence neuAc-alpha-2,3-gal-beta-1,3-galNAc- found on sugar chains O-linked to Thr or Ser & also as a terminal sequence on certain gangliosides
- SIAT4A & SIAT4B sialylate the same acceptor substrates but exhibit different Km values
- protein modification; protein glycosylation
- the soluble form derives from the membrane form by proteolytic processing
CMP-N-acetylneuraminate +
beta-D-galactosyl-1,3-N-acetyl-alpha-D-galactosaminyl-R
CMP + alpha-N-acetylneuraminyl-2,3-beta-D-galactosyl-1,3-N- acetyl-alpha-D-galactosaminyl-R
Structure: belongs to the glycosyltransferase 29 family
Compartment:
- Golgi, Golgi stack membrane
- secreted
- membrane-bound form in trans cisternae of Golgi
- secreted into the body fluid
Expression:
- expressed in several tissues
- highest expression in lung, liver, skeletal muscle, kidney, pancreas, spleen & placenta
General
galactosyltransferase
glycoprotein
membrane protein
sialyltransferase
Properties
SIZE: entity length = 340 aa
MW = 39 kD
COMPARTMENT: golgi
MOTIF: transmembrane domain {14-34}
N-glycosylation site {N79}
N-glycosylation site {N114}
cysteine residue {C142}
MODIFICATION: cysteine residue {C281}
N-glycosylation site {N201}
cysteine residue {C281}
MODIFICATION: cysteine residue {C142}
N-glycosylation site {N323}
Database Correlations
OMIM 607187
UniProt Q11201
Pfam PF00777
Entrez Gene 6482
Kegg hsa:6482
ENZYME 2.4.99.4
References
- UniProt :accession Q11201
- GGDB; Note: glycogene database
http://ggdb.muse.aist.go.jp/GGDB/index.jsp