Enzymes
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- Name help_outline a N-(2-hydroxyacyl)sphing-4-enine Identifier CHEBI:16456 Charge 0 Formula C20H38NO4R SMILEShelp_outline CCCCCCCCCCCCC\C=C\[C@@H](O)[C@H](CO)NC(=O)C(O)[*] 2D coordinates Mol file for the small molecule Search links Involved in 3 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 a 1-(β-D-galactosyl)-2-(2-hydroxyacyl)sphing-4-enine Identifier CHEBI:16994 Charge 0 Formula C26H48NO9R SMILEShelp_outline CCCCCCCCCCCCC\C=C\[C@@H](O)[C@H](CO[C@@H]1O[C@H](CO)[C@H](O)[C@H](O)[C@H]1O)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 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 9,431 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 576 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Cross-references
| RHEA:10856 | RHEA:10857 | RHEA:10858 | RHEA:10859 | |
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| Reaction direction help_outline | undefined | left-to-right | right-to-left | bidirectional |
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Related reactions help_outline
More general form(s) of this reaction
Publications
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The biosynthesis by brain microsomes of cerebrosides containing nonhydroxy fatty acids.
Morell P., Costantino-Ceccarini E., Radin N.S.
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Enzymatic synthesis of galactocerebroside by a galactosyltransferase from embryonic chicken brain.
Basu S., Schultz A.M., Basu M., Roseman S.
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Synthesis of cerebroside by brain from uridine diphosphate galactose and ceramide containing hydroxy fatty acid.
Morell P., Radin N.S.
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Reversal of non-hydroxy:alpha-hydroxy galactosylceramide ratio and unstable myelin in transgenic mice overexpressing UDP-galactose:ceramide galactosyltransferase.
Fewou S.N., Bussow H., Schaeren-Wiemers N., Vanier M.T., Macklin W.B., Gieselmann V., Eckhardt M.
The sphingolipids galactosylceramide and sulfatide are important for the formation and maintenance of myelin. Transgenic mice overexpressing the galactosylceramide synthesizing enzyme UDP-galactose:ceramide galactosyltransferase in oligodendrocytes display an up to four-fold increase in UDP-galact ... >> More
The sphingolipids galactosylceramide and sulfatide are important for the formation and maintenance of myelin. Transgenic mice overexpressing the galactosylceramide synthesizing enzyme UDP-galactose:ceramide galactosyltransferase in oligodendrocytes display an up to four-fold increase in UDP-galactose:ceramide galactosyltransferase activity, which correlates with an increase in its products monogalactosyl diglyceride and non-hydroxy fatty acid-containing galactosylceramide. Surprisingly, however, we observed a concomitant decrease in alpha-hydroxylated galactosylceramide such that total galactosylceramide in transgenic mice was almost unaltered. These data suggest that UDP-galactose:ceramide galactosyltransferase activity does not limit total galactosylceramide level. Furthermore, the predominance of alpha-hydroxylated galactosylceramide appeared to be determined by the extent to which non-hydroxylated ceramide was galactosylated rather than by the higher affinity of UDP-galactose:ceramide galactosyltransferase for alpha-hydroxy fatty acid ceramide. The protein composition of myelin was unchanged with the exception of significant up-regulation of the myelin and lymphocyte protein. Transgenic mice were able to form myelin, which, however, was apparently unstable and uncompacted. These mice developed a progressive hindlimb paralysis and demyelination in the CNS, demonstrating that tight control of UDP-galactose:ceramide galactosyltransferase expression is essential for myelin maintenance. << Less
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UDP-galactose:ceramide galactosyltransferase is a class I integral membrane protein of the endoplasmic reticulum.
Sprong H., Kruithof B., Leijendekker R., Slot J.W., van Meer G., van der Sluijs P.
UDP-galactose:ceramide galactosyltransferase (CGalT) transfers UDP-galactose to ceramide to form the glycosphingolipid galactosylceramide. Galactosylceramide is the major constituent of myelin and is also highly enriched in many epithelial cells, where it is thought to play an important role in li ... >> More
UDP-galactose:ceramide galactosyltransferase (CGalT) transfers UDP-galactose to ceramide to form the glycosphingolipid galactosylceramide. Galactosylceramide is the major constituent of myelin and is also highly enriched in many epithelial cells, where it is thought to play an important role in lipid and protein sorting. Although the biochemical pathways of glycosphingolipid biosynthesis are relatively well understood, the localization of the enzymes involved in these processes has remained controversial. We here have raised antibodies against CGalT and shown by immunocytochemistry on ultrathin cryosections that the enzyme is localized to the endoplasmic reticulum and nuclear envelope but not to the Golgi apparatus or the plasma membrane. In pulse-chase experiments, we have observed that newly synthesized CGalT remains sensitive to endoglycosidase H, confirming the results of the morphological localization experiments. In protease protection assays, we show that the largest part of the protein, including the amino terminus, is oriented toward the lumen of the endoplasmic reticulum. CGalT enzyme activity required import of UDP-galactose into the lumen of the endoplasmic reticulum by a UDP-galactose translocator that is present in the Golgi apparatus of CHO cells but absent in CHOlec8 cells. Finally, we show that CGalT activity previously observed in Golgi membrane fractions in vitro, in the absence of UDP-glucose, is caused by UDP-glucose:ceramide glucosyltransferase. Therefore all galactosylceramide synthesis occurs by CGalT in vivo in the lumen of the endoplasmic reticulum. << Less
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Ceramide UDPgalactosyltransferase from myelinating rat brain: purification, cloning, and expression.
Schulte S., Stoffel W.
Cerebrosides and sulfatides are major glycosphingolipids of the lipid bilayer of the myelin sheath assembled by oligodendrocytes and Schwann cells during myelination. Cerebrosides are synthesized by ceramide UDPgalactosyltransferase [CGT; 2-hydroxyacylsphinogosine 1-beta-galactosyl-transferase; UD ... >> More
Cerebrosides and sulfatides are major glycosphingolipids of the lipid bilayer of the myelin sheath assembled by oligodendrocytes and Schwann cells during myelination. Cerebrosides are synthesized by ceramide UDPgalactosyltransferase [CGT; 2-hydroxyacylsphinogosine 1-beta-galactosyl-transferase; UDPgalactose:2-(2-hydroxyacyl)sphingosine 1-beta-D-galactosyltransferase; UDPgalactose:2-(2-hydroxyacyl)sphingosine 1-beta-D-galactosyltransferase, EC 2.4.1.45] with UDPgalactose and ceramide as substrates. Here we describe a purification method from microsomes of myelinating rat brains that includes ion exchange, dye ligand, and lectin affinity chromatography. The enzyme was identified as a 64-kDa high-mannose glycoprotein. A CGT-specific cDNA clone was isolated from a rat brain cDNA library using CGT oligonucleotides derived from peptide sequences. The cDNA insert encodes a polypeptide of 541 amino acid residues with a molecular weight of 61,126. The polypeptide has three putative glycosylation sites and one hydrophobic domain at the C terminus. A 20-residue N-terminal signal sequence is lost during cotranslational translocation. Northern blot analysis demonstrates that CGT expression is restricted to brain tissue and is time dependent, correlating with myelin basic protein expression. In situ hybridization reveals that CGT expression is restricted to the oligodendrocyte-containing cell layers of cerebrum and cerebellum, which also express myelin basic protein. The amino acid sequence of CGT shows significant homology to mammalian UDPglucuronyltransferases, which suggests a common evolutionary origin of these enzymes. << Less
Proc. Natl. Acad. Sci. U.S.A. 90:10265-10269(1993) [PubMed] [EuropePMC]
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UDP-galactose:ceramide galactosyltransferase of rat central-nervous-system myelin.
Koul O., Jungalwala F.B.
The properties of ceramide galactosyltransferase associated with myelin and microsomal fractions of rat brain were studied. The enzyme from both the fractions had similar properties during development and synthesized the same molecular species of the product cerebroside. The results suggested that ... >> More
The properties of ceramide galactosyltransferase associated with myelin and microsomal fractions of rat brain were studied. The enzyme from both the fractions had similar properties during development and synthesized the same molecular species of the product cerebroside. The results suggested that during myelination the turnover rate of enzyme protein is altered instead of regulatory modulation of the enzyme protein. << Less