Abstract
The presence of cytosolic S-adenosylmethionine-dependent N-methyltransferase(s) activity(ies) capable of converting phosphoethanolamine into phosphocholine has been recently demonstrated in the rat brain. At least two enzymes are involved in the methylation of phosphoethanolamine to phosphocholine and these are separable by ammonium sulphate fractionation. The enzyme catalysing the last step of this methylation process is present in the 50-80% ammonium sulphate fraction. A 220-fold purified enzyme has been obtained with sequentially employed Q-Sepharose fast flow and octyl-Sepharose CL4B column chromatography. The maximum enzyme activity was at pH 9.5. The Km values for S-adenosylmethionine, the methyl donor, and phosphodimethylethanolamine, the methyl acceptor, were 125 microM and 750 microM respectively. This phosphodimethylethanolamine N-methyltransferase was found to be calcium-dependent, with a 4-fold increase in activity at 0.5 mM-CaCl2. S-Adenosylhomocysteine at 0.5 mM caused 100% inhibition of the activity. The effects of various structural analogues on the phosphodimethylethanolamine N-methyltransferase activity were also investigated and these results suggest that the enzyme is specific to the substrate. These results provide evidence for the existence of the pathway for the methylation of phosphoethanolamine to phosphocholine in rat brain cytosol.
Full text
PDF





Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Andriamampandry C., Freysz L., Kanfer J. N., Dreyfus H., Massarelli R. Conversion of ethanolamine, monomethylethanolamine and dimethylethanolamine to choline-containing compounds by neurons in culture and by the rat brain. Biochem J. 1989 Dec 1;264(2):555–562. doi: 10.1042/bj2640555. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Andriamampandry C., Freysz L., Kanfer J. N., Dreyfus H., Massarelli R. Effect of monomethylethanolamine, dimethylethanolamine, gangliosides, isoproterenol, and 2-hydroxyethylhydrazine on the conversion of ethanolamine to methylated products by cultured chick brain neurons. J Neurochem. 1991 Jun;56(6):1845–1850. doi: 10.1111/j.1471-4159.1991.tb03439.x. [DOI] [PubMed] [Google Scholar]
- Andriamampandry C., Massarelli R., Freysz L., Kanfer J. N. A rat brain cytosolic N-methyltransferase(s) activity converting phosphorylethanolamine into phosphorylcholine. Biochem Biophys Res Commun. 1990 Sep 14;171(2):758–763. doi: 10.1016/0006-291x(90)91211-a. [DOI] [PubMed] [Google Scholar]
- BARTLETT G. R. Phosphorus assay in column chromatography. J Biol Chem. 1959 Mar;234(3):466–468. [PubMed] [Google Scholar]
- Blusztajn J. K., Liscovitch M., Richardson U. I. Synthesis of acetylcholine from choline derived from phosphatidylcholine in a human neuronal cell line. Proc Natl Acad Sci U S A. 1987 Aug;84(15):5474–5477. doi: 10.1073/pnas.84.15.5474. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Blusztajn J. K., Wurtman R. J. Choline biosynthesis by a preparation enriched in synaptosomes from rat brain. Nature. 1981 Apr 2;290(5805):417–418. doi: 10.1038/290417a0. [DOI] [PubMed] [Google Scholar]
- Blusztajn J. K., Zeisel S. H., Wurtman R. J. Synthesis of lecithin (phosphatidylcholine) from phosphatidylethanolamine in bovine brain. Brain Res. 1979 Dec 28;179(2):319–327. doi: 10.1016/0006-8993(79)90447-5. [DOI] [PubMed] [Google Scholar]
- Buchanan A. G., Kanfer J. N. The effects of various incubation temperatures, particulate isolation, and possible role of calmodulin on the activity of the base exchange enzymes of rat brain. J Neurochem. 1980 Oct;35(4):815–822. doi: 10.1111/j.1471-4159.1980.tb07077.x. [DOI] [PubMed] [Google Scholar]
- Chiang P. K., Cantoni G. L. Perturbation of biochemical transmethylations by 3-deazaadenosine in vivo. Biochem Pharmacol. 1979 Jun 15;28(12):1897–1902. doi: 10.1016/0006-2952(79)90642-7. [DOI] [PubMed] [Google Scholar]
- Crews F. T., Hirata F., Axelrod J. Identification and properties of methyltransferases that synthesize phosphatidylcholine in rat brain synaptosomes. J Neurochem. 1980 Jun;34(6):1491–1498. doi: 10.1111/j.1471-4159.1980.tb11229.x. [DOI] [PubMed] [Google Scholar]
- Datko A. H., Aksamit R. R., Mudd S. H. Phosphatidylcholine synthesis in the rat: the substrate for methylation and regulation by choline. Lipids. 1990 Mar;25(3):135–142. doi: 10.1007/BF02544327. [DOI] [PubMed] [Google Scholar]
- Esko J. D., Matsuoka K. Y. Biosynthesis of phosphatidylcholine from serum phospholipids in Chinese hamster ovary cells deprived of choline. J Biol Chem. 1983 Mar 10;258(5):3051–3057. [PubMed] [Google Scholar]
- Imamura S., Horiuti Y. Purification of Streptomyces chromofuscus phospholipase D by hydrophobic affinity chromatography on palmitoyl cellulose. J Biochem. 1979 Jan;85(1):79–95. doi: 10.1093/oxfordjournals.jbchem.a132334. [DOI] [PubMed] [Google Scholar]
- Jope R. S. High affinity choline transport and acetylCoA production in brain and their roles in the regulation of acetylcholine synthesis. Brain Res. 1979 Dec;180(3):313–344. doi: 10.1016/0165-0173(79)90009-2. [DOI] [PubMed] [Google Scholar]
- KENNEDY E. P., WEISS S. B. The function of cytidine coenzymes in the biosynthesis of phospholipides. J Biol Chem. 1956 Sep;222(1):193–214. [PubMed] [Google Scholar]
- Kanfer J. N. Base exchange reactions of the phospholipids in rat brain particles. J Lipid Res. 1972 Jul;13(4):468–476. [PubMed] [Google Scholar]
- LOWRY O. H., ROSEBROUGH N. J., FARR A. L., RANDALL R. J. Protein measurement with the Folin phenol reagent. J Biol Chem. 1951 Nov;193(1):265–275. [PubMed] [Google Scholar]
- Lee H. S., Schulz A. R., Fuller R. W. Isolation and purification of rabbit adrenal norephinephrine N-methyl transferase isozymes. Arch Biochem Biophys. 1978 Jan 15;185(1):222–227. doi: 10.1016/0003-9861(78)90162-5. [DOI] [PubMed] [Google Scholar]
- Masland R. H., Mills J. W. Choline accumulation by photoreceptor cells of the rabbit retina. Proc Natl Acad Sci U S A. 1980 Mar;77(3):1671–1675. doi: 10.1073/pnas.77.3.1671. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Mozzi R., Porcellati G. Conversion of phosphatidylethanolamine to phosphatidylcholine in rat brain by the methylation pathway. FEBS Lett. 1979 Apr 15;100(2):363–366. doi: 10.1016/0014-5793(79)80370-1. [DOI] [PubMed] [Google Scholar]
- Pajares M. A., Villalba M., Mato J. M. Purification of phospholipid methyltransferase from rat liver microsomal fraction. Biochem J. 1986 Aug 1;237(3):699–705. doi: 10.1042/bj2370699. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Pelech S. L., Pritchard P. H., Sommerman E. F., Percival-Smith A., Vance D. E. Glucagon inhibits phosphatidylcholine biosynthesis via the CDP-choline and transmethylation pathways in cultured rat hepatocytes. Can J Biochem Cell Biol. 1984 Apr;62(4):196–202. doi: 10.1139/o84-028. [DOI] [PubMed] [Google Scholar]
- Pelech S. L., Pritchard P. H., Vance D. E. cAMP analogues inhibit phosphatidylcholine biosynthesis in cultured rat hepatocytes. J Biol Chem. 1981 Aug 25;256(16):8283–8286. [PubMed] [Google Scholar]
- Porcellati G., Arienti G., Pirotta M., Giorgini D. Base-exchange reactions for the synthesis of phospholipids in nervous tissue: the incorporation of serine and ethanolamine into the phospholipids of isolated brain microsomes. J Neurochem. 1971 Aug;18(8):1395–1417. doi: 10.1111/j.1471-4159.1971.tb00004.x. [DOI] [PubMed] [Google Scholar]
- Pritchard P. H., Chiang P. K., Cantoni G. L., Vance D. E. Inhibition of phosphatidylethanolamine N-methylation by 3-deazaadenosine stimulates the synthesis of phosphatidylcholine via the CDP-choline pathway. J Biol Chem. 1982 Jun 10;257(11):6362–6367. [PubMed] [Google Scholar]
- Pritchard P. H., Pelech S. L., Vance D. E. Analogues of cyclic AMP inhibit phosphatidylethanolamine N-methylation by cultured rat hepatocytes. Biochim Biophys Acta. 1981 Nov 23;666(2):301–306. doi: 10.1016/0005-2760(81)90122-3. [DOI] [PubMed] [Google Scholar]
- Ridgway N. D., Vance D. E. Purification of phosphatidylethanolamine N-methyltransferase from rat liver. J Biol Chem. 1987 Dec 15;262(35):17231–17239. [PubMed] [Google Scholar]
- Sedmak J. J., Grossberg S. E. A rapid, sensitive, and versatile assay for protein using Coomassie brilliant blue G250. Anal Biochem. 1977 May 1;79(1-2):544–552. doi: 10.1016/0003-2697(77)90428-6. [DOI] [PubMed] [Google Scholar]
- Takayama M., Itoh S., Nagasaki T., Tanimizu I. A new enzymatic method for determination of serum choline-containing phospholipids. Clin Chim Acta. 1977 Aug 15;79(1):93–98. doi: 10.1016/0009-8981(77)90465-x. [DOI] [PubMed] [Google Scholar]
- Tucek S. Problems in the organization and control of acetylcholine synthesis in brain neurons. Prog Biophys Mol Biol. 1984;44(1):1–46. doi: 10.1016/0079-6107(84)90011-7. [DOI] [PubMed] [Google Scholar]
- Vance D. E. Boehringer Mannheim Award lecture. Phosphatidylcholine metabolism: masochistic enzymology, metabolic regulation, and lipoprotein assembly. Biochem Cell Biol. 1990 Oct;68(10):1151–1165. doi: 10.1139/o90-172. [DOI] [PubMed] [Google Scholar]
- Vance D. E., de Kruijff B. The possible functional significance of phosphatidylethanolamine methylation. Nature. 1980 Nov 20;288(5788):277–279. doi: 10.1038/288277a0. [DOI] [PubMed] [Google Scholar]
- Varela I., Mérida I., Pajares M., Villalba M., Mato J. M. Activation of partially purified rat liver lipid methyltransferase by phosphorylation. Biochem Biophys Res Commun. 1984 Aug 16;122(3):1065–1070. doi: 10.1016/0006-291x(84)91199-9. [DOI] [PubMed] [Google Scholar]
- Villalba M., Pajares M. A., Renart M. F., Mato J. M. Protein kinase C catalyses the phosphorylation and activation of rat liver phospholipid methyltransferase. Biochem J. 1987 Feb 1;241(3):911–916. doi: 10.1042/bj2410911. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Weinshilboum R. M., Raymond F. A. Calcium inhibition of rat liver catechol-O-methyltransferase. Biochem Pharmacol. 1976 Mar 1;25(5):573–579. doi: 10.1016/0006-2952(76)90390-7. [DOI] [PubMed] [Google Scholar]
- Yamamoto K., Niwa A., Yasumura Y. Continuous growth and phosphatidylcholine synthesis of rat hepatoma cells in choline-deprived chemically defined medium. J Cell Physiol. 1985 Oct;125(1):91–97. doi: 10.1002/jcp.1041250112. [DOI] [PubMed] [Google Scholar]
