Enzymes
UniProtKB help_outline | 2,333 proteins |
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- Name help_outline CDP-choline Identifier CHEBI:58779 (Beilstein: 4170622) help_outline Charge -1 Formula C14H25N4O11P2 InChIKeyhelp_outline RZZPDXZPRHQOCG-OJAKKHQRSA-M SMILEShelp_outline C[N+](C)(C)CCOP([O-])(=O)OP([O-])(=O)OC[C@H]1O[C@H]([C@H](O)[C@@H]1O)n1ccc(N)nc1=O 2D coordinates Mol file for the small molecule Search links Involved in 19 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline a 1,2-diacyl-sn-glycerol Identifier CHEBI:17815 Charge 0 Formula C5H6O5R2 SMILEShelp_outline OC[C@@H](COC([*])=O)OC([*])=O 2D coordinates Mol file for the small molecule Search links Involved in 198 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline a 1,2-diacyl-sn-glycero-3-phosphocholine Identifier CHEBI:57643 Charge 0 Formula C10H18NO8PR2 SMILEShelp_outline [C@](COC(=O)*)(OC(=O)*)([H])COP(OCC[N+](C)(C)C)([O-])=O 2D coordinates Mol file for the small molecule Search links Involved in 325 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline CMP Identifier CHEBI:60377 Charge -2 Formula C9H12N3O8P InChIKeyhelp_outline IERHLVCPSMICTF-XVFCMESISA-L SMILEShelp_outline Nc1ccn([C@@H]2O[C@H](COP([O-])([O-])=O)[C@@H](O)[C@H]2O)c(=O)n1 2D coordinates Mol file for the small molecule Search links Involved in 166 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:32939 | RHEA:32940 | RHEA:32941 | RHEA:32942 | |
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Reaction direction help_outline | undefined | left-to-right | right-to-left | bidirectional |
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Related reactions help_outline
Specific form(s) of this reaction
Publications
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Cloning and expression of a human choline/ethanolaminephosphotransferase: synthesis of phosphatidylcholine and phosphatidylethanolamine.
Henneberry A.L., McMaster C.R.
Cholinephosphotransferase catalyses the final step in the synthesis of phosphatidylcholine (PtdCho) via the Kennedy pathway by the transfer of phosphocholine from CDP-choline to diacylglycerol. Ethanolaminephosphotransferase catalyses an analogous reaction with CDP-ethanolamine as the phosphobase ... >> More
Cholinephosphotransferase catalyses the final step in the synthesis of phosphatidylcholine (PtdCho) via the Kennedy pathway by the transfer of phosphocholine from CDP-choline to diacylglycerol. Ethanolaminephosphotransferase catalyses an analogous reaction with CDP-ethanolamine as the phosphobase donor for the synthesis of phosphatidylethanolamine (PtdEtn). Together these two enzyme activities determine both the site of synthesis and the fatty acyl composition of PtdCho and PtdEtn synthesized de novo. A human choline/ethanolaminephosphotransferase cDNA (hCEPT1) was cloned, expressed and characterized. Northern blot analysis revealed one hCEPT1 2.3 kb transcript that was ubiquitous and not enriched, with respect to actin, in any particular cell type. The open reading frame predicts a protein (hCEPT1p) of 416 amino acid residues with a molecular mass of 46550 Da containing seven membrane-spanning domains. A predicted amphipathic helix resides within the active site of the enzyme with the final two aspartic residues of the CDP-alcohol phosphotransferase motif, DG(X)2AR(X)8G(X)3D(X)3D, positioned within this helix. hCEPT1p was successfully expressed in a full-length, active form in Saccharomyces cerevisiae cells devoid of endogenous cholinephosphotransferase or ethanolaminephosphotransferase activities (HJ091, cpt1::LEU2 ept1-). In vitro, hCEPT1p displayed broad substrate specificity, utilizing both CDP-choline and CDP-ethanolamine as phosphobase donors to a broad range of diacylglycerols, resulting in the synthesis of both PtdCho and PtdEtn. In vivo, S. cerevisiae cells (HJ091, cpt1::LEU2 ept1-) expressing hCEPT1 efficiently incorporated both radiolabelled choline and ethanolamine into phospholipids, demonstrating that hCEPT1p has the ability to synthesize both choline- and ethanolamine- containing phospholipids in vitro and in vivo. << Less
Biochem. J. 339:291-298(1999) [PubMed] [EuropePMC]
This publication is cited by 10 other entries.
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sn-1,2-diacylglycerol choline- and ethanolaminephosphotransferases in Saccharomyces cerevisiae. Mixed micellar analysis of the CPT1 and EPT1 gene products.
Hjelmstad R.H., Bell R.M.
The Saccharomyces cerevisiae CPT1 and EPT1 genes are structural genes encoding distinct sn-1,2-diacylglycerol choline- and ethanolaminephosphotransferases. A haploid cpt1 ept1 double null mutant lacked detectable choline- and ethanolaminephosphotransferase activity but was viable for growth, estab ... >> More
The Saccharomyces cerevisiae CPT1 and EPT1 genes are structural genes encoding distinct sn-1,2-diacylglycerol choline- and ethanolaminephosphotransferases. A haploid cpt1 ept1 double null mutant lacked detectable choline- and ethanolaminephosphotransferase activity but was viable for growth, establishing that these enzymes are nonessential. The activities of the CPT1 and EPT1 gene products were independently studied in membranes prepared from strains mutant in the cognate locus using mixed micellar assays. Both enzymes absolutely required phospholipid cofactors; half-maximal activation was observed at low mole fractions, suggesting that a small number of phospholipid molecules are required. The activities of the CPT1 and EPT1 gene products were compared with respect to dioleoylglycerol dependence, CDP-aminoalcohol specificity, phospholipid activation, and inhibition by CMP. The EPT1 gene product utilized CDP-ethanolamine, -monomethylethanolamine, -dimethylethanolamine, and -choline to significant extents, while the CPT1 gene product manifested relative specificity for CDP-choline and -dimethylethanolamine. The CPT1 and EPT1 gene products exhibited differing properties with respect to phospholipid activation, but this difference was dependent on the CDP-aminoalcohol substrate. In contrast, the two enzymes could be distinguished on the basis of their dioleoylglycerol dependencies, activation by Mg2+, and CMP inhibition profiles regardless of the CDP-aminoalcohol substrate employed. These studies provide the first definitive kinetic properties of individual choline- and ethanolaminephosphotransferases. << Less
J. Biol. Chem. 266:4357-4365(1991) [PubMed] [EuropePMC]
This publication is cited by 5 other entries.
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Biosynthesis of 1-alkyl-2-acetyl-sn-glycero-3-phosphocholine (platelet activating factor and a hypotensive lipid) by cholinephosphotransferase in various rat tissues.
Renooij W., Snyder F.
The unique alkyl phospholipid, 1-alkyl-2-acetyl-sn-glycero-3-phosphocholine, has been reported to exhibit powerful antihypertensive activity (Blank, M.L., Snyder, F., Byers, L.W., Brooks, B. and Muirhead, E.E. (1979) Biochem. Biophys. Res. Commun. 90, 1194-1200) and appears to be an extremely pote ... >> More
The unique alkyl phospholipid, 1-alkyl-2-acetyl-sn-glycero-3-phosphocholine, has been reported to exhibit powerful antihypertensive activity (Blank, M.L., Snyder, F., Byers, L.W., Brooks, B. and Muirhead, E.E. (1979) Biochem. Biophys. Res. Commun. 90, 1194-1200) and appears to be an extremely potent platelet-activating factor (Demopoulos, C.A., Pinckard, R.N. and Hanahan, D.J. (1979) J. Biol. Chem. 254, 9355-9358). In the present study, microsomal preparations from several rat tissues were found to catalyze the synthesis of 1-alkyl-1-acetyl-sn-glycero-3-phosphocholine by 1-alkyl-2-acetyl-sn-glycerol:CDPcholine cholinephosphotransferase reaction. Optimal conditions to measure enzyme activity were established. A subcellular survey of this cholinephosphotransferase activity showed that the enzyme was of microsomal origin. Enzyme activity was found in microsomes from several tissues; however, spleen has the highest activity of the tissues examined. Three different species of 1-alkyl-2-acetyl-sn-glycerol were all found to be substrates. The 1-alkyl-2-acetyl-sn-glycero-3-phosphocholine synthesized in the microsomes could be hydrolyzed by adding the 100,000 x g supernatant fraction to the incubation medium. The optimum pH for formation of 1-alkyl-2-acetyl-sn-glycero-3-phosphocholine was 8.0, which was different from the pH optimum of 8.5 observed for the long-chain diacylglycerol cholinephosphotransferases. Activity of cholinephosphotransferase towards 1-alkyl-2-acetyl-sn-glycerol was slightly enhanced and stabilized by dithiothreitol, whereas the activity towards a diacylglycerol was inhibited by dithiothreitol. The possible involvement of two different enzymes in the conversion of 1-alkyl-2-acetyl-sn-glycerol and diacylglycerol to their respective phospholipid products is discussed. << Less
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Structure of a eukaryotic cholinephosphotransferase-1 reveals mechanisms of substrate recognition and catalysis.
Wang L., Zhou M.
Phosphatidylcholine (PC) is the most abundant phospholipid in eukaryotic cell membranes. In eukaryotes, two highly homologous enzymes, cholinephosphotransferase-1 (CHPT1) and choline/ethanolamine phosphotransferase-1 (CEPT1) catalyze the final step of de novo PC synthesis. CHPT1/CEPT1 joins two su ... >> More
Phosphatidylcholine (PC) is the most abundant phospholipid in eukaryotic cell membranes. In eukaryotes, two highly homologous enzymes, cholinephosphotransferase-1 (CHPT1) and choline/ethanolamine phosphotransferase-1 (CEPT1) catalyze the final step of de novo PC synthesis. CHPT1/CEPT1 joins two substrates, cytidine diphosphate-choline (CDP-choline) and diacylglycerol (DAG), to produce PC, and Mg<sup>2+</sup> is required for the reaction. However, mechanisms of substrate recognition and catalysis remain unresolved. Here we report structures of a CHPT1 from Xenopus laevis (xlCHPT1) determined by cryo-electron microscopy to an overall resolution of ~3.2 Å. xlCHPT1 forms a homodimer, and each protomer has 10 transmembrane helices (TMs). The first 6 TMs carve out a cone-shaped enclosure in the membrane in which the catalysis occurs. The enclosure opens to the cytosolic side, where a CDP-choline and two Mg<sup>2+</sup> are coordinated. The structures identify a catalytic site unique to eukaryotic CHPT1/CEPT1 and suggest an entryway for DAG. The structures also reveal an internal pseudo two-fold symmetry between TM3-6 and TM7-10, and suggest that CHPT1/CEPT1 may have evolved from their distant prokaryotic ancestors through gene duplication. << Less