Role of sulfhydryl groups in phospholipid methylation reactions of cardiac sarcolemma

Roland Vetter, Jian Dai, Nasrin Mesaeli, Vincenzo Panagia, Naranjan S. Dhalla

Research output: Contribution to journalArticle

7 Citations (Scopus)


The effect of reagents that modify sulfur-containing amino acid residues in the phosphatidylethanolamine N-methyltransferase was studied in the isolated rat cardiac sarcolemma by employing S-adenosyl-L-[methyl-3H]methionine as a methyl donor. Dithiothreitol protected the sulfhydryl groups in the membrane and caused a concentration- and time-dependent increase of phospholipid N-methylation at three different catalytic sites. This stimulation was highest (9-fold) in the presence of 1 MM MgCl2 and 0.1 μM S-adenosyl-L-[methyl-3H]methionine at pH 8.0 (catalytic site 1), and was associated with an enhancement of Vmax without changes in Km for the methyl donor. Thiol glutathione was less stimulatory than dithiothreitol; glutathione disulfide inhibited the phosphatidylethanolamine N-methylation by 50%. The alkylating reagents, N-ethylmaleimide and methylmethanethiosulfonate, inhibited the N-methylation with IC5O of 6.9 and 14.1 μM, respectively; this inhibition was prevented by 1 mM dithiothreitol. These results indicate a critical role of sulfhydryl groups for the activity of the cardiac sarcolemmal phosphatidylethanolamine N-methyltransferase and suggest that this enzyme system in cardiac sarcolemma may be controlled by the glutathione/glutathione disulfide redox state in the cell.

Original languageEnglish
Pages (from-to)85-96
Number of pages12
JournalMolecular and Cellular Biochemistry
Issue number1
Publication statusPublished - 1 Apr 1991


  • S-adenosyl-L-methionine
  • neutral lipid methylation
  • phospholipid N-methylation
  • rat heart
  • sarcolemma
  • sulfhydryl groups

ASJC Scopus subject areas

  • Molecular Biology
  • Clinical Biochemistry
  • Cell Biology

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