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

More general terms

• sialyltransferase
• galactosyltransferase
• membrane protein
• glycoprotein

Database

• UniProt: http://www.uniprot.org/uniprot/Q11201.html
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:6482
• OMIM: https://mirror.omim.org/entry/607187
• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=6482