Enzymes
| UniProtKB help_outline | 411 proteins |
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- Name help_outline a β-D-galactosyl-(1→4)-N-acetyl-β-D-glucosaminyl derivative Identifier CHEBI:133507 Charge 0 Formula C14H24NO11R SMILEShelp_outline [C@@H]1([C@@H]([C@H]([C@H]([C@H](O1)CO)O)O)O)O[C@H]2[C@@H]([C@H]([C@@H](O[C@@H]2CO)O*)NC(=O)C)O 2D coordinates Mol file for the small molecule Search links Involved in 8 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline UDP-α-D-galactose Identifier CHEBI:66914 Charge -2 Formula C15H22N2O17P2 InChIKeyhelp_outline HSCJRCZFDFQWRP-ABVWGUQPSA-L SMILEShelp_outline OC[C@H]1O[C@H](OP([O-])(=O)OP([O-])(=O)OC[C@H]2O[C@H]([C@H](O)[C@@H]2O)n2ccc(=O)[nH]c2=O)[C@H](O)[C@@H](O)[C@H]1O 2D coordinates Mol file for the small molecule Search links Involved in 105 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline an α-D-galactosyl-(1→3)-β-D-galactosyl-(1→4)-N-acetyl-β-D-glucosaminyl derivative Identifier CHEBI:138024 Charge 0 Formula C20H34NO16R SMILEShelp_outline [C@@H]1([C@@H]([C@H]([C@@H]([C@H](O1)CO)O[C@H]2[C@@H]([C@H]([C@H]([C@H](O2)CO)O)O[C@@H]3[C@@H]([C@H]([C@H]([C@H](O3)CO)O)O)O)O)O)NC(=O)C)O* 2D coordinates Mol file for the small molecule Search links Involved in 1 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline UDP Identifier CHEBI:58223 Charge -3 Formula C9H11N2O12P2 InChIKeyhelp_outline XCCTYIAWTASOJW-XVFCMESISA-K SMILEShelp_outline O[C@@H]1[C@@H](COP([O-])(=O)OP([O-])([O-])=O)O[C@H]([C@@H]1O)n1ccc(=O)[nH]c1=O 2D coordinates Mol file for the small molecule Search links Involved in 577 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline H+ Identifier CHEBI:15378 Charge 1 Formula H InChIKeyhelp_outline GPRLSGONYQIRFK-UHFFFAOYSA-N SMILEShelp_outline [H+] 2D coordinates Mol file for the small molecule Search links Involved in 9,521 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Cross-references
| RHEA:13013 | RHEA:13014 | RHEA:13015 | RHEA:13016 | |
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| Reaction direction help_outline | undefined | left-to-right | right-to-left | bidirectional |
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Publications
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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).
Blake D.A., Goldstein I.J.
An alpha-D-galactosyltransferase activity has been detected in membranous fractions (42,000 x g) of Ehrlich ascites cells which transfers galactosyl groups from UDP-galactose to endogenous and exogenous acceptors. The products of the reaction contain alpha-D-galactopyranosyl groups at the nonreduc ... >> More
An alpha-D-galactosyltransferase activity has been detected in membranous fractions (42,000 x g) of Ehrlich ascites cells which transfers galactosyl groups from UDP-galactose to endogenous and exogenous acceptors. The products of the reaction contain alpha-D-galactopyranosyl groups at the nonreducing termini. A solid state assay was developed to follow alpha-D-galactosyltransferase activity in the presence of beta-D-galactosyltransferase. Examination of a variety of insolubilized exogenous acceptors indicated that the most active acceptors for the alpha-D-galactosyltransferase had the structure beta-D-Gal-(1 goes to 4)-beta-D-GlcNAc(1 goes to at their nonreducing termini. Incubation of UDP-[14C]galactose and beta-D-gal-(1 goes to 4)-D-GlcNAc (N-acetyllactosamine) or of UDP-galactose and beta-D-[14C]Gal-(1 goes to 4)-D-GlcNAc in the presence of the alpha-D-galactosyltransferase resulted in the enzymic synthesis of a 14C-labeled trisaccharide. Chemical and enzymic methods of analysis revealed the structure of the trisaccharide to be alpha-D-Gal-(1 goes to 3)-beta-D-Gal-(1 goes to 4)-D-GlcNAc. These data indicate that the alpha-D-galactosyltransferase in Ehrlich ascites cells transfers galactosyl groups to suitable acceptors to form an alpha-(1 goes to 3)-D-galactosidic linkage. << Less
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Site-directed mutagenesis of glutamate 317 of bovine alpha-1,3Galactosyltransferase and its effect on enzyme activity: implications for reaction mechanism.
Molina P., Knegtel R.M., Macher B.A.
Bovine alpha1,3galactosyltransferase (alpha1,3GalT) transfers galactose from UDP-alpha-galactose to terminal beta-linked galactosyl residues with retention of configuration of the incoming galactose residue. The epitope synthesized has been shown to be critical for xenotransplantation. According t ... >> More
Bovine alpha1,3galactosyltransferase (alpha1,3GalT) transfers galactose from UDP-alpha-galactose to terminal beta-linked galactosyl residues with retention of configuration of the incoming galactose residue. The epitope synthesized has been shown to be critical for xenotransplantation. According to a proposed double-displacement reaction mechanism, glutamate-317 (E317) is thought to be the catalytic nucleophile. The proposed catalytic role of E317 involves an initial nucleophilic attack with inversion of configuration and formation of a covalent sugar-enzyme intermediate between E317 and galactose from the donor substrate, followed by a second nucleophilic attack performed by the acceptor substrate with a second inversion of configuration. To determine whether E317 of alpha1,3GalT is critical for enzyme activity, site-directed mutagenesis was used to substitute alanine, aspartic acid, cysteine and histidine for E317. If the proposed reaction mechanism for the alpha1,3GalT enzyme is correct, E317D and E317H would produce active enzymes since they can act as nucleophiles. The non-conservative mutation E317A and conservative mutation E317C are predicted to produce inactive or very low activity enzymes since the E317A mutant cannot engage in a nucleophilic attack, and the E317C mutant would trap the galactose residue. The results obtained demonstrate that E317D and E317H mutants retained activity, albeit significantly less than the wild-type enzyme. Additionally, both E317A and E317C mutant also retained enzyme activity, suggesting that E317 is not the catalytic nucleophile proposed in the double-displacement mechanism. Therefore, either a different amino acid may act as the catalytic nucleophile or the reaction must proceed by a different mechanism. << Less
Biochim Biophys Acta 1770:1266-1273(2007) [PubMed] [EuropePMC]
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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.
Blanken W.M., Van den Eijnden D.H.
A UDP-Gal:Gal beta 1----4GlcNAc-R alpha 1----3- and a UDP-Gal:GlcNAc-R beta 1----4-galactosyltransferase have been purified 44,000- and 101,000-fold, respectively, from a Triton X-100 extract of calf thymus by affinity chromatography on UDP-hexanolamine-Sepharose and alpha-lactalbumin-Sepharose in ... >> More
A UDP-Gal:Gal beta 1----4GlcNAc-R alpha 1----3- and a UDP-Gal:GlcNAc-R beta 1----4-galactosyltransferase have been purified 44,000- and 101,000-fold, respectively, from a Triton X-100 extract of calf thymus by affinity chromatography on UDP-hexanolamine-Sepharose and alpha-lactalbumin-Sepharose in a yield of 25-40%. Sodium dodecyl sulfate gel electrophoresis under reducing conditions revealed a major polypeptide species with a molecular weight of 40,000 and a minor form at Mr 42,000 for the alpha 1----3-galactosyltransferase and a major polypeptide with Mr 51,000 for the beta 1----4-galactosyltransferase. Analytical gel filtration on Sephadex G-100 yielded a monomeric form for each of the galactosyltransferases with Mr 43,000 and 59,000 respectively, in addition to peaks of activity at higher molecular weights. Isoelectric focussing of the alpha 1----3-galactosyltransferase revealed a significant charge heterogeneity with forms varying in pI values between 5.0 and 6.5. Acceptor specificity studies indicated that the purified alpha 1----3-galactosyltransferase was free from contaminating galactosyltransferase activities such as those involved in the synthesis of Gal beta 1----4GlcNAc-R and Gal beta 1----3GalNAc-R sequences, the blood group B determinant, the Pk antigen, trihexosylceramide, and ganglioside GM1. The alpha 1----3-galactosyltransferase appeared to be highly active with glycoproteins, oligosaccharides, and glycolipids having a terminal Gal beta 1----4GlcNAc beta 1----unit such as asialo-alpha 1-acid glycoprotein (Km = 1.25 mM), Gal beta 1----4GlcNAc beta 1----2Man alpha 1----3Man beta 1----4GlcNAc (Km = 0.57 mM), and paragloboside. The action of the alpha 1----3-galactosyltransferase was found to be mutually exclusive with that of the NeuAc:Gal beta 1----4GlcNAc-R alpha 2----6-sialyltransferase from bovine colostrum. In addition alpha 1----3-fucosylation of the N-acetylglucosamine residue in the preferred disaccharide acceptor structure completely blocked galactosylation of the alpha 1----3-galactosyltransferase. << Less
J Biol Chem 260:12927-12934(1985) [PubMed] [EuropePMC]
This publication is cited by 2 other entries.
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Fold recognition study of alpha3-galactosyltransferase and molecular modeling of the nucleotide sugar-binding domain.
Imberty A., Monier C., Bettler E., Morera S., Freemont P., Sippl M., Flockner H., Ruger W., Breton C.
The structure and fold of the enzyme responsible for the biosynthesis of the xenotransplantation antigen, namely pig alpha3 galactosyltransferase, has been studied by means of computational methods. Secondary structure predictions indicated that alpha3-galactosyltransferase and related protein fam ... >> More
The structure and fold of the enzyme responsible for the biosynthesis of the xenotransplantation antigen, namely pig alpha3 galactosyltransferase, has been studied by means of computational methods. Secondary structure predictions indicated that alpha3-galactosyltransferase and related protein family members, including blood group A and B transferases and Forssman synthase, are likely to consist of alternating alpha-helices and beta-strands. Fold recognition studies predicted that alpha3-galactosyltransferase shares the same fold as the T4 phage DNA-modifying enzyme beta-glucosyltransferase. This latter enzyme displays a strong structural resemblance with the core of glycogen phosphorylase b. By using the three-dimensional structure of beta-glucosyltransferase and of several glycogen phosphorylases, the nucleotide binding domain of pig alpha3-galactosyltransferase was built by knowledge-based methods. Both the UDP-galactose ligand and a divalent cation were included in the model during the refinement procedure. The final three-dimensional model is in agreement with our present knowledge of the biochemistry and mechanism of alpha3-galactosyltransferases. << Less
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Enzymatic synthesis of a blood group B-related pentaglycosylceramide by an alpha-galactosyltransferase from rabbit bone marrow.
Basu M., Basu S.