Neurochemical Research

, Volume 20, Issue 10, pp 1233–1237 | Cite as

Partial purification of a phosphoethanolamine methyltransferase from rat brain cytosol

  • Subrata Mukherjee
  • Louis Freysz
  • Julian N. Kanfer
Original Articles


The conversion of phosphoethanolamine to phosphocholine requires 3 separate N-methyltransferases. We had previously purified the enzyme catalyzing the last methylation, phosphodimethylethanolamine N-methyltransferase. We have successfully purified the enzyme catalyzing the initial methylation of phosphoethanolamine. A 434 fold purified enzyme from rat brain was obtained by the sequential use of ammonium sulfate fractionation, Q-Sepharose fast flow column chromatography and a ω-aminoethyl agarose column chromatography. The pH optimum was 11 or greater, the Km value for phosphoethanolamine was 167.8±41.7 μM and the Vmax was 487.3±85 mmoles/mg/hr. The kinetics for S-adenosyl-methionine, the methyldonor, has characteristics of cooperative binding with a Km of 1.805±0.59 mM and a Vmax of 16.9±3.6 μmoles/mg/hr. The activity was stimulated 6 fold by 2.5 mM MnCl2 and inhibited by DZA and S-adenosylhomocysteine. These results reinforce the early in vivo observations which had provided suggestive evidence for the existence of a pathway for the methylation of phosphoethanolamine to phosphocholine in rat brain.

Key words

Phosphoethanolamine methytransferase choline rat brain 

Abbreviations used






3-(cyclohexyl)amino-1-propanesulphonic acid












phenylmethanesulphonyl fluoride












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Copyright information

© Plenum Publishing Corporation 1995

Authors and Affiliations

  • Subrata Mukherjee
    • 1
  • Louis Freysz
    • 2
  • Julian N. Kanfer
    • 1
  1. 1.Departmet of Biochemistry and Molecular BiologyUniversity of ManitobaWinnipegCanada
  2. 2.Cenre d'NeurochimieStrasbourgFrance

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