N-acetyllactosaminide 3-alpha-galactosyltransferase

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In enzymology, a N-acetyllactosaminide 3-alpha-galactosyltransferase (EC 2.4.1.87) is an enzyme that catalyzes the chemical reaction

UDP-galactose + beta-D-galactosyl-(1->4)-beta-N-acetyl-D-glucosaminyl-R $\rightleftharpoons$ UDP + alpha-D-galactosyl-(1->3)-beta-D-galactosyl-(1->4)-beta-N- acetylglucosaminyl-R

Thus, the two substrates of this enzyme are UDP-galactose and [[beta-D-galactosyl-(1->4)-beta-N-acetyl-D-glucosaminyl-R]], whereas its 3 products are UDP, [[alpha-D-galactosyl-(1->3)-beta-D-galactosyl-(1->4)-beta-N-]], and acetylglucosaminyl-R.

This enzyme belongs to the family of glycosyltransferases, specifically the hexosyltransferases. The systematic name of this enzyme class is UDP-galactose:N-acetyllactosaminide 3-alpha-D-galactosyltransferase. Other names in common use include alpha-galactosyltransferase, UDP-Gal:beta-D-Gal(1,4)-D-GlcNAc alpha(1,3)-galactosyltransferase, UDP-Gal:N-acetyllactosaminide alpha(1,3)-galactosyltransferase, UDP-Gal:N-acetyllactosaminide alpha-1,3-D-galactosyltransferase, UDP-Gal:Galbeta1->4GlcNAc-R alpha1->3-galactosyltransferase, UDP-galactose-acetyllactosamine alpha-D-galactosyltransferase, UDPgalactose:beta-D-galactosyl-beta-1,4-N-acetyl-D-glucosaminyl-, glycopeptide alpha-1,3-D-galactosyltransferase, glucosaminylglycopeptide alpha-1,3-galactosyltransferase, uridine diphosphogalactose-acetyllactosamine, alpha1->3-galactosyltransferase, uridine diphosphogalactose-acetyllactosamine galactosyltransferase, uridine, diphosphogalactose-, galactosylacetylglucosaminylgalactosylglucosylceramide, galactosyltransferase, beta-D-galactosyl-N-acetylglucosaminylglycopeptide, and alpha-1,3-galactosyltransferase. This enzyme participates in 3 metabolic pathways: glycosphingolipid biosynthesis - lactoseries, glycosphingolipid biosynthesis - neo-lactoseries, and glycan structures - biosynthesis 2.

1 Structural studies
2 References
3 External links
- 3.1 Gene Ontology (GO) codes

[edit] Structural studies

As of late 2007, 3 structures have been solved for this class of enzymes, with PDB accession codes 2JCF, 2JCK, and 2JCL.

[edit] References

IUBMB entry for 2.4.1.87
BRENDA references for 2.4.1.87 (Recommended.)
PubMed references for 2.4.1.87
PubMed Central references for 2.4.1.87
Google Scholar references for 2.4.1.87
Basu M, Basu S (1973). "Enzymatic synthesis of a blood group B-related pentaglycosylceramide by an alpha-galactosyltransferase from rabbit bone marrow". J. Biol. Chem. 248: 1700–6. PMID 4632915.
Blanken WM, Van den Eijnden DH (1985). "Biosynthesis of terminal Gal alpha 1--3Gal beta 1--4GlcNAc-R oligosaccharide sequences on glycoconjugates. Purification and acceptor specificity of a UDP-Gal:N-acetyllactosaminide alpha 1--3-galactosyltransferase from calf thymus". J. Biol. Chem. 260: 12927–34. PMID 3932335.
Blake DA, Goldstein IJ (1981). "An alpha-D-galactosyltransferase activity in Ehrlich ascites tumor cells. Biosynthesis and characterization of a trisaccharide (alpha-D-galactose-(1 goes to 3)-N-acetyllactosamine)". J. Biol. Chem. 256: 5387–93. PMID 6787040.