| N-acetyllactosaminide alpha-2,3-sialyltransferase | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Identifiers | |||||||||
| EC no. | 2.4.99.6 | ||||||||
| CAS no. | 77537-85-0 | ||||||||
| Databases | |||||||||
| IntEnz | IntEnz view | ||||||||
| BRENDA | BRENDA entry | ||||||||
| ExPASy | NiceZyme view | ||||||||
| KEGG | KEGG entry | ||||||||
| MetaCyc | metabolic pathway | ||||||||
| PRIAM | profile | ||||||||
| PDB structures | RCSB PDB PDBe PDBsum | ||||||||
| Gene Ontology | AmiGO / QuickGO | ||||||||
| |||||||||
In enzymology, a N-acetyllactosaminide alpha-2,3-sialyltransferase (EC 2.4.99.6) is an enzyme that catalyzes the chemical reaction
- CMP-N-acetylneuraminate + beta-D-galactosyl-1,4-N-acetyl-D-glucosaminyl-glycoprotein CMP + alpha-N-acetylneuraminyl-2,3-beta-D-galactosyl-1,4-N-acetyl-D- glucosaminyl-glycoprotein
Thus, the two substrates of this enzyme are CMP-N-acetylneuraminate and beta-D-galactosyl-1,4-N-acetyl-D-glucosaminyl-glycoprotein, whereas its 3 products are CMP, alpha-N-acetylneuraminyl-2,3-beta-D-galactosyl-1,4-N-acetyl-D-, and glucosaminyl-glycoprotein.
This enzyme belongs to the family of transferases, specifically those glycosyltransferases that do not transfer hexosyl or pentosyl groups. The systematic name of this enzyme class is CMP-N-acetylneuraminate:beta-D-galactosyl-1,4-N-acetyl-D-glucosaminy l-glycoprotein alpha-2,3-N-acetylneuraminyltransferase. Other names in common use include sialyltransferase, cytidine, monophosphoacetylneuraminate-beta-galactosyl(1-, >4)acetylglucosaminide alpha2->3-sialyltransferase, alpha2->3 sialyltransferase, and SiaT. This enzyme participates in 4 metabolic pathways: keratan sulfate biosynthesis, glycosphingolipid biosynthesis - lactoseries, glycan structures - biosynthesis 1, and glycan structures - biosynthesis 2.
Structural studies
As of late 2007, two structures have been solved for this class of enzymes, with PDB accession codes 2EX0 and 2EX1.
References
- Van den Eijnden DH, Schiphorst WE (1981). "Detection of beta-galactosyl(1 leads to 4)N-acetylglucosaminide alpha(2 leads to 3)-sialyltransferase activity in fetal calf liver and other tissues". J. Biol. Chem. 256 (7): 3159–62. PMID 7204397.