Skip to main content
NCBI home page
Plant Physiology logoLink to Plant Physiology
. 1992 Nov;100(3):1536–1540. doi: 10.1104/pp.100.3.1536

Phosphatidylcholine Synthesis in Castor Bean Endosperm 1

Occurrence of an S-Adenosyl-l-Methionine:Ethanolamine N-Methyltransferase

Marie-Pascale Prud'homme 1,2, Thomas S Moore Jr 1
PMCID: PMC1075816  PMID: 16653154

Abstract

Methylethanolamine synthesis by S-adenosyl-l-methionine:ethanolamine N-methyltransferase from an extract of castor bean (Ricinus communis L. var Hale) endosperm was characterized. The apparent Michaelis-Menten constants of the enzyme for ethanolamine and S-adenosyl-l-methionine were estimated to be 6.7 and 1.4 μm, respectively, although the Km for ethanolamine is imprecise because of strong substrate inhibition. The pH optimum was 8.0, and a divalent cation was required for activity, with Mg2+ giving the greatest stimulation at 5 mm. The enzyme was inhibited by calcium in the micromolar range and relatively high concentrations of ethanolamine (above about 7 μm). The activity was found in the 119,000g supernatant fraction and, therefore, appears to be cytoplasmic. The potential roles of S-adenosyl-l-methionine:ethanolamine N-methyltransferase in choline and phosphatidylcholine synthesis are discussed.

Full text

PDF
1536

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Bradford M. M. A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. Anal Biochem. 1976 May 7;72:248–254. doi: 10.1016/0003-2697(76)90527-3. [DOI] [PubMed] [Google Scholar]
  2. Datko A. H., Mudd S. H. Enzymes of phosphatidylcholine synthesis in lemna, soybean, and carrot. Plant Physiol. 1988 Dec;88(4):1338–1348. doi: 10.1104/pp.88.4.1338. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Datko A. H., Mudd S. H. Phosphatidylcholine synthesis: differing patterns in soybean and carrot. Plant Physiol. 1988 Nov;88(3):854–861. doi: 10.1104/pp.88.3.854. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Fett W. F., Dunn M. F. Exopolysaccharides Produced by Phytopathogenic Pseudomonas syringae Pathovars in Infected Leaves of Susceptible Hosts. Plant Physiol. 1989 Jan;89(1):5–9. doi: 10.1104/pp.89.1.5. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. GREENE R. C., DAVIS N. B. Biosynthesis of S-methylmethionine in the jack bean. Biochim Biophys Acta. 1960 Sep 23;43:360–362. doi: 10.1016/0006-3002(60)90457-1. [DOI] [PubMed] [Google Scholar]
  6. Kinney A. J., Moore T. S., Jr Phosphatidylcholine synthesis in castor bean endosperm: characteristics and reversibility of the choline kinase reaction. Arch Biochem Biophys. 1988 Jan;260(1):102–108. doi: 10.1016/0003-9861(88)90429-8. [DOI] [PubMed] [Google Scholar]
  7. Kinney A. J., Moore T. S. Phosphatidylcholine Synthesis in Castor Bean Endosperm : I. Metabolism of l-Serine. Plant Physiol. 1987 May;84(1):78–81. doi: 10.1104/pp.84.1.78. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Macher B. A., Mudd J. B. Partial purification and properties of ethanolamine kinase from spinach leaf. Arch Biochem Biophys. 1976 Nov;177(1):24–30. doi: 10.1016/0003-9861(76)90411-2. [DOI] [PubMed] [Google Scholar]
  9. Mudd S. H., Datko A. H. Phosphoethanolamine bases as intermediates in phosphatidylcholine synthesis by lemna. Plant Physiol. 1986 Sep;82(1):126–135. doi: 10.1104/pp.82.1.126. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Mudd S. H., Datko A. H. Synthesis of methylated ethanolamine moieties: regulation by choline in lemna. Plant Physiol. 1989 May;90(1):296–305. doi: 10.1104/pp.90.1.296. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Mudd S. H., Datko A. H. Synthesis of methylated ethanolamine moieties: regulation by choline in soybean and carrot. Plant Physiol. 1989 May;90(1):306–310. doi: 10.1104/pp.90.1.306. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Prud'homme M. P., Moore T. S. Phosphatidylcholine synthesis in castor bean endosperm : free bases as intermediates. Plant Physiol. 1992 Nov;100(3):1527–1535. doi: 10.1104/pp.100.3.1527. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Wang X., Moore T. S. Phosphatidylcholine biosynthesis in castor bean endosperm : purification and properties of cytidine 5'-triphosphate:choline-phosphate cytidylyltransferase. Plant Physiol. 1990 May;93(1):250–255. doi: 10.1104/pp.93.1.250. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Wharfe J., Harwood J. L. Lipid metabolism in germinating seeds. Purification of ethanolamine kinase from soya bean. Biochim Biophys Acta. 1979 Oct 26;575(1):102–111. doi: 10.1016/0005-2760(79)90135-8. [DOI] [PubMed] [Google Scholar]

Articles from Plant Physiology are provided here courtesy of Oxford University Press

RESOURCES