, Volume 32, Issue 4, pp 351–358 | Cite as

Phospholipid biosynthetic enzymes in human brain

  • Brian M. Ross
  • Anna Moszczynska
  • Jan K. Blusztajn
  • Allan Sherwin
  • Andres Lozano
  • Stephen J. Kish


Growing evidence suggests an involvement of brain membrane phospholipid metabolism in a variety of neurodegenerative and psychiatric conditions. This has prompted the use of drugs (e.g., CDPcholine) aimed at elevating the rate of neural membrane synthesis. However, no information is available regarding the human brain enzymes of phospholipid synthesis which these drugs affect. Thus, the objective of our study was to characterize the enzymes involved, in particular, whether differences existed in the relative affinity of substrates for the enzymes of phosphatidylethanolamine (PE) compared to those of phosphatidylcholine (PC) synthesis. The concentration of choline in rapidly frozen human brain biopsies ranged from 32–186 nmol/g tissue, a concentration similar to that determined previously for ethanolamine. Since human brain ethanolamine kinase possessed a much lower affinity for ethanolamine (Km=460 μM) than choline kinase did for choline (Km=17 μM), the activity of ethanolamine kinase in vivo may be more dependent on substrate availability than that of choline kinase. In addition, whereas ethanolamine kinase was inhibited by choline, and to a lesser extent by phosphocholine, choline kinase activity was unaffected by the presence of ethanolamine, or phosphoethanolamine, and only weakly inhibited by phosphocholine. Phosphoethanolamine cytidylyl-transferase (PECT) and phosphocholine cytidylyltransferase (PCCT) also displayed dissimilar characteristics, with PECT and PCCT being located predominantly in the cytosolic and particulate fractions, respectively. Both PECT and PCCT exhibited a low affinity for CTP (Km approximately 1.2 mM), suggesting that the activities of these enzymes, and by implication, the rate of phospholipid synthesis, are highly dependent upon the cellular concentration of CTP. In conclusion, our data indicate different regulatory properties of PE and PC synthesis in human brain, and suggest that the rate of PE synthesis may be more dependent upon substrate (ethanolamine) availability than that of PC synthesis.





phosphocholine cytidylyltransferase




phosphoethanolamine cytidylyltransferase


thin-layer chromatography


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  1. 1.
    Kent, C. (1991) Regulation of Phosphatidylcholine Biosynthesis, Prog. Lipid Res. 29, 87–105.CrossRefGoogle Scholar
  2. 2.
    Nitsch, R.M., Blusztajn, J.K., Pittas, A.G., Slack, B.E., Growdon, J.H., and Wurtman, R.J. (1992) Evidence for a Membrane Defect in Alzheimer Disease Brain, Proc. Natl. Acad. Sci. USA 89, 1671–1675.PubMedCrossRefGoogle Scholar
  3. 3.
    Cuénod, C.-A., Kaplan, D.B., Michot, J.-L., Jehenson, P., Leroy-Willig, A., Forette, F., Syrota, A., and Boller, F. (1995) Phospholipid Abnormalities in Early Alzheimer’s Disease, Arch. Neurol. 52, 89–94.PubMedGoogle Scholar
  4. 4.
    Rordorf, G., Uemura, Y., and Bonventre, J.V. (1991) Characterisation of Phospholipase A2 (PLA2) Activity in Gerbil Brain: Enhanced Activities of Cytosolic, Mitochondrial, and Microsomal Forms After Ischemia and Reperfusion, J. Neurosci. 11, 1829–1836.PubMedGoogle Scholar
  5. 5.
    Moto, A., Hirashima, Y., Endo, S., and Takaku, A. (1991) Changes in Lipid Metabolites and Enzymes in Rat Brain Due to Ischemia and Recirculation, Mol. Chem. Neuropath. 14, 35–51.CrossRefGoogle Scholar
  6. 6.
    Pettegrew, J.W., Keshavan, M.S., and Minshew, N.J. (1993) 31P Nuclear Magnetic Resonance Spectroscopy: Neurodevelopment and Schizophrenia, J. Neural Transm. 36, 35–53.Google Scholar
  7. 7.
    Stanley, J.A., Williamson, P.C., Drost, D.J., Carr, T.J., Rylett, J., Malla, A., and Thompson, T. (1995) An in vivo Study of the Prefrontal Cortex of Schizophrenic Patients at Different Stages of Illness via Phosphorus Magnetic Resonance Spectroscopy, Arch. Gen. Psychiatry 52, 399–406.PubMedGoogle Scholar
  8. 8.
    Ross, B.M., Hudson, C., Erlich, J., Warsh, J.J., and Kish, S.J. Increased Phospholipid Breakdown in Schizophrenia: Evidence for the Involvement of a Calcium-Independent Phospholipase A2 Activity, Arch. Gen. Psychiatry, in press.Google Scholar
  9. 9.
    Nitsch, R.M., Blusztajn, J.K., Doyle, F.M., Robitaille, Y., Wurtman, R.J., Growdon, J.H., and Kish, S.J. (1993) Phospholipid Metabolite Levels Are Altered in Cerebral Cortex of Patients with Dominantly Inherited Olivopontocerebellar Atrophy, Neurosci. Lett. 161, 191–194.PubMedCrossRefGoogle Scholar
  10. 10.
    Kish, S.J., Robitaille, Y., Ball, M., Gilbert, J., Deck, J.H.N., Chang, L.J., and Schut, L. (1990) Glycerophosphoethanolamine Concentration Is Elevated in Brain of Patients with Dominantly Inherited Olivopontocerebellar Atrophy, Neurosci. Lett. 120, 209–211.PubMedCrossRefGoogle Scholar
  11. 11.
    Lopez-Coviella, I., and Wurtman, R.J. (1992) Enhancement by Cytidine of Brain Membrane Phospholipid Synthesis, J. Neurochem. 59, 338–343.CrossRefGoogle Scholar
  12. 12.
    Clark, W.M., and Warach, S.J. (1996) Randomized Dose Response Trial of Citicoline in Acute Ischemia Stroke Patients, Neurology 46 (Suppl.), A424.Google Scholar
  13. 13.
    Tazaki, Y., Sakai, F., Otomo, E., Kutsuzawa, T., Kameyama, M., Omae, T., Fujishima, M., and Sakuma, A. (1988) Treatment of Acute Cerebral Infarction with a Choline Precursor in a Multicenter Double-Blind Placebo Controlled Study, Stroke 19, 1073–1080.Google Scholar
  14. 14.
    Catalyad, M.V., Catalyud Perez, J.B., and Aso Escario, J. (1991) Effects of CDP-choline on the Recovery of Patients with Head Injury, J. Neurol. Sci. 103 (suppl.), S15-S18.Google Scholar
  15. 15.
    Spiers, P.A., Myers, D., Hochandel, G.S., Lieberman, H.R., and Wurtman, R.J. (1996) Citicoline Improves Verbal Memory in Aging, Arch. Neurol. 53, 441–448.PubMedGoogle Scholar
  16. 16.
    Lopez-Coviella, I., Agut, J., Von Borstel, R., and Wurtman, R.J. (1987) Metabolism of Cytidine (5′)-Diphosphocholine (Citicoline) Following Oral and Intravenous Administration to the Human and Rat, Neurochem. Int. 11, 293–297.CrossRefGoogle Scholar
  17. 17.
    Lopez-Coviella, I., Agut, J., Savci, V., Ortiz, J.A., and Wurtman, R.J. (1995) Evidence That 5′-Cytidinediphosphocholine Can Affect Brain Phospholipid Composition by Increasing Choline and Cytidine Plasma Levels, J. Neurochem. 65, 889–894.PubMedCrossRefGoogle Scholar
  18. 18.
    Ross, B.M., and Kish, S.J. (1994) Characterisation of Lysophospholipid Metabolising Enzymes in Human Brain, J. Neurochem. 63, 1839–1848.PubMedCrossRefGoogle Scholar
  19. 19.
    Ross, B.M., Sherwin, A.L., and Kish, S.J. (1995) Multiple Forms of the Enzyme Glycerophosphodiesterase Are Present in Human Brain, Lipids 30, 1075–1081.PubMedGoogle Scholar
  20. 20.
    Sundler, R. (1975) Ethanolamine Cytidylyltransferase, J. Biol. Chem. 250, 8585–8590.PubMedGoogle Scholar
  21. 21.
    Folch, J., Lees, M., and Sloane-Stanley, G.H. (1957) A Simple Method for the Isolation and Purification of Total Lipids from Animal Tissues, J. Biol. Chem. 226, 497–509.PubMedGoogle Scholar
  22. 22.
    Fersht, A. (1985) The Basic Equations of Enzyme Kinetics, in Enzyme Structure and Mechanism, pp. 98–120, W.H. Freeman and Company, New York.Google Scholar
  23. 23.
    Klein, J., Gonzalez, R., Koppen, A., and Loffelholz, K. (1993) Free Choline and Choline Metabolites in Rat Brain and Body Fluids: Sensitive Determination and Implications for Choline Supply to the Brain, Neurochem. Int. 22, 293–300.PubMedCrossRefGoogle Scholar
  24. 24.
    Marshall, D.L., De Micheli, E., Bogdanov, M.B., and Wurtman, R.J. (1996) Effects of Ethanolamine (ETN) Administration on ETN and Choline (CH) Levels in Plasma, Brain Extracellular Fluid (ECF) and Brain Tissue, and on Brain Phospholipid Levels in Rats: An in vivo Study, Neurosci. Res. Comm. 18, 87–96.CrossRefGoogle Scholar
  25. 25.
    Perry, T.L., Hansen, S., and Gandham, S.S. (1981) Postmortem Changes of Amino Compounds in Human and Rat Brain, J. Neurochem. 36, 406–412.PubMedCrossRefGoogle Scholar
  26. 26.
    Houweling, M., Tijburg, L.B.M., Vaartjes, W.J., and Van Golde, L.M.G. (1992) Phosphatidylethanolamine Metabolism in Rat Liver After Partial Hepatectomy, Biochem. J. 283, 55–61.PubMedGoogle Scholar
  27. 27.
    Haines, D.S., and Derksen, D.H. (1972) Changes in Metabolism of Ethanolamine and Its Derivatives in Liver During Fasting, Can. J. Biochem. 53, 51–56.Google Scholar
  28. 28.
    Schneider, W.J., and Vance, D.E. (1978) Effect of Choline Deficiency on the Enzymes That Synthesize Phosphatidylcholine and Phosphatidylethanolamine in Rat Liver, Eur. J. Biochem. 85, 181–187.PubMedCrossRefGoogle Scholar
  29. 29.
    Percy, A.K., and Moore, J.F. (1994) Choline Deficiency in Cultured Adrenal Medullary Cells: Effect on Phosphatidylcholine Biosynthesis, Bioch. Med. Metab. Biol. 51, 169–174.CrossRefGoogle Scholar
  30. 30.
    Zelinski, T.A., and Choy, P.C. (1982) Choline Regulates Phosphatidylethanolamine Biosynthesis in Isolated Hamster Heart, J. Biol. Chem. 257, 13201–13204.PubMedGoogle Scholar
  31. 31.
    Mages, F., Rey, C., Fonplut, P., and Pacheco, H. (1988) Kinetic and Biochemical Properties of CTP: Choline-Phosphate Cytidylyltransferase from the Rat Brain, Eur. J. Biochem. 178, 367–372.PubMedCrossRefGoogle Scholar
  32. 32.
    Tuburg, L.B.M., Vermeulen, P.S., and Van Golde, L.M.G. (1992) Ethanolamine Cytidylyltransferase, Meth. Enzymol. 209, 258–263.CrossRefGoogle Scholar
  33. 33.
    Vermeulen, P.S., Tijburg, L.B.M., Geelen, M.J.H., and van Golde, L.M.G. (1993) Immunological Characterisation, Lipid Dependence, and Subcellular Localisation of CTP:Phosphoethanolamine Cytidylyltransferase Purified from Rat Liver, J. Biol. Chem. 268, 7458–7464.PubMedGoogle Scholar
  34. 34.
    Wang, Y., and Kent, C. (1995) Effects of Altered Phosphorylation Sites on the Properties of CTP:Phosphocholine Cytidylyltransferase, J. Biol. Chem. 270, 17843–17849.PubMedCrossRefGoogle Scholar
  35. 35.
    Yang, W., Boggs, K.P., and Jackowski, S. (1995) The Association of Lipid Activators with the Amphipathic Helical Domain of CTP:Phosphocholine Cytidylyltransferase Accelerates Catalysis by Increasing the Affinity of the Enzyme for CTP, J. Biol. Chem. 270, 23951–23957.PubMedCrossRefGoogle Scholar
  36. 36.
    Abe, K., Kogure, K., Yamamoto, H., Imazawa, M., and Miyamoto, K. (1987) Mechanism of Arachidonic Acid Liberation During Ischemia in Gerbil Cerebral Cortex, J. Neurochem. 48, 503–509.PubMedCrossRefGoogle Scholar
  37. 37.
    Lopez-Coviella, I., Agut, J., and Wurtman, R.J. (1992) Effects of Orally Administered Cytidine 5′-Diphosphate Choline on Brain Phospholipid Content, J. Nutr. Biochem. 3, 313–315.CrossRefGoogle Scholar
  38. 38.
    Savci, V., and Wurtman, R.J. (1995) Effect of Cytidine on Membrane Phospholipid Synthesis in Rat Striatal Slices, J. Neurochem. 64, 378–384.PubMedCrossRefGoogle Scholar
  39. 39.
    Agut, J., Lopez-Coviella, I., Ortiz, J.A., and Wurtman, R.J. (1993) Oral Cytidine 5′-Diphosphate Choline Administration to Rats Increases Brain Phospholipid Levels, Ann. N.Y. Acad. Sci. 695, 318–320.PubMedGoogle Scholar
  40. 40.
    Weinhold, P.A., Charles, L.G., and Feldman, D.A. (1991) Microsomal CTP:Choline Phosphate Cytidylyltransferase: Kinetic Mechanism of Fatty Acid Stimulation, Biochim. Biophys. Acta 1086, 57–62.PubMedGoogle Scholar
  41. 41.
    Sweitzer, T.D., and Kent, C. (1994) Expression of Wild-Type and Mutant Rat Liver CTP:Phosphocholine Cytidylyltransferase in a Cytidylyltransferase-Deficient Chinese Hamster Ovary Cell Line, Arch. Biochem. Biophys. 311, 107–116.PubMedCrossRefGoogle Scholar
  42. 42.
    Beley, A., Bertrand, N., and Beley, P. (1991) Cerebral Ischemia: Changes in Brain Choline, Acetylcholine, and Other Monoamines as Related to Energy Metabolism, Neurochem. Res. 16, 555–561.PubMedCrossRefGoogle Scholar
  43. 43.
    Millington, W.R., and Wurtman, R.J. (1982) Choline Administration Elevates Brain Phosphorylcholine Concentrations, J. Neurochem. 38, 1748–1752.PubMedCrossRefGoogle Scholar
  44. 44.
    George, T.P, Morash, S.C., Cook, H.W., Byers, D.M., Palmer, F.B., and Spence, M.W. Phosphatidylcholine Biosynthesis in Cultured Glioma Cells: Evidence for the Channeling of Intermediates, Biochim. Biophys. Acta 1004, 283–291.Google Scholar

Copyright information

© AOCS Press 1997

Authors and Affiliations

  • Brian M. Ross
    • 1
  • Anna Moszczynska
    • 5
  • Jan K. Blusztajn
    • 3
  • Allan Sherwin
    • 4
  • Andres Lozano
    • 2
  • Stephen J. Kish
    • 1
    • 5
  1. 1.Department of PsychiatryUniversity of TorontoTorontoCanada
  2. 2.Toronto HospitalTorontoCanada
  3. 3.Department of PathologyBoston University Medical SchoolBoston
  4. 4.Montreal Neurological InstituteMontrealCanada
  5. 5.Human Neurochemical Pathology LaboratoryClarke Institute of PsychiatryTorontoCanada

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