KEGG   ENZYME: 2.4.99.2Help
Entry
EC 2.4.99.2                 Enzyme                                 

Name
beta-D-galactosyl-(1->3)-N-acetyl-beta-D-galactosaminide alpha-2,3-sialyltransferase;
CMP-N-acetylneuraminate:D-galactosyl-N-acetyl-D-galactosaminyl-(N-acetylneuraminyl)-D-galactosyl-D-glucosyl-(1<->1)-ceramide N-acetylneuraminyltransferase (ambiguous);
monosialoganglioside sialyltransferase;
CMP-N-acetylneuraminate:a beta-D-galactosyl-(1->3)-N-acetyl-beta-D-galactosaminyl-(1->4)-[alpha-N-acetylneuraminyl-(2->3)]-beta-D-galactosyl-(1->4)-beta-D-glucosyl-(1<->1)-ceramide N-acetyl-beta-neuraminyltransferase
Class
Transferases;
Glycosyltransferases;
Transferring other glycosyl groups
BRITE hierarchy
Sysname
CMP-N-acetyl-beta-neuraminate:a beta-D-galactosyl-(1->3)-N-acetyl-beta-D-galactosaminyl-R alpha-(2->3)-N-acetylneuraminyltransferase (configuration-inverting)
Reaction(IUBMB)
CMP-N-acetyl-beta-neuraminate + a beta-D-galactosyl-(1->3)-N-acetyl-beta-D-galactosaminyl-R = CMP + an N-acetyl-alpha-neuraminyl-(2->3)-beta-D-galactosyl-(1->3)-N-acetyl-beta-D-galactosaminyl-R [RN:R11715]
Reaction(KEGG)
R11715;
(other) R04648 R05942(G)
Show
Substrate
CMP-N-acetyl-beta-neuraminate [CPD:C00128];
beta-D-galactosyl-(1->3)-N-acetyl-beta-D-galactosaminyl-R
Product
CMP [CPD:C00055];
N-acetyl-alpha-neuraminyl-(2->3)-beta-D-galactosyl-(1->3)-N-acetyl-beta-D-galactosaminyl-R [CPD:C04885]
Comment
The enzyme recognizes the sequence beta-D-galactosyl-(1->3)-N-acetyl-D-galactosaminyl (known as type 1 histo-blood group precursor disaccharide) in non-reducing termini of glycan moieties in glycoproteins and glycolipids [1]. When acting on gangloside GM1a, it forms gangloside GD1a [2].
History
EC 2.4.99.2 created 1976, modified 1986, modified 2017
Reference
1  [PMID:438198]
  Authors
Rearick JI, Sadler JE, Paulson JC, Hill RL.
  Title
Enzymatic characterization of beta D-galactoside alpha2 leads to 3 sialyltransferase from porcine submaxillary gland.
  Journal
J. Biol. Chem. 254 (1979) 4444-51.
Reference
2  [PMID:4351506]
  Authors
Yip MC.
  Title
The enzymic synthesis of disialoganglioside: rat brain cytidine-5'-monophospho-N-acetylneuraminic acid: monosialoganglioside (G M1 ) sialyltransferase.
  Journal
Biochim. Biophys. Acta. 306 (1973) 298-306.
Other DBs
ExplorEnz - The Enzyme Database: 
IUBMB Enzyme Nomenclature: 
ExPASy - ENZYME nomenclature database: 
BRENDA, the Enzyme Database: 
CAS: 
60202-12-2

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