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. 1995 Jul;48(7):641–644. doi: 10.1136/jcp.48.7.641

Thiol methyltransferase activity in colonocytes and erythrocyte membranes.

W J Babidge 1, S H Millard 1, W E Roediger 1
PMCID: PMC502715  PMID: 7560171

Abstract

AIMS--To verify the improved thiol methyltransferase (TMT) assay and measure activity in isolated colonocytes and erythrocyte membranes of the same subjects. METHODS--High performance liquid chromatography with radioactivity detection was used to measure 14C-methylmercaptoethanol formation, the reaction product of cell extracts incubated with mercaptoethanol and 14C-S-adenosylmethionine. RESULTS--Verification of radiolabelled 14C-methylmercaptoethanol was by exogenous addition of methylmercaptoethanol and simultaneous ultraviolet detection at 214 nm. Using a substrate concentration of 10 mM mercaptoethanol, the Km for S-adenosylmethionine was 25 microM. The sensitivity of the radioactive method was 2 pmol, with coefficients of variation of 7% within assay and 6.4% between assay. TMT activities (mean +/- SE; n = 17) were 471 +/- 64 pmol/hour/mg protein for colonocytes and 73 +/- 7 pmol/hour/mg protein for erythrocyte membranes. CONCLUSIONS--The direct assay of TMT activity is sensitive, specific and eliminates concern over non-enzymatic methylation of thiol compounds. High activities in colonic epithelial cells deserve evaluation in disease states.

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Selected References

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

  1. Bradley H., Waring R. H., Emery P. Reduced thiol methyl transferase activity in red blood cell membranes from patients with rheumatoid arthritis. J Rheumatol. 1991 Dec;18(12):1787–1789. [PubMed] [Google Scholar]
  2. Glauser T. A., Kerremans A. L., Weinshilboum R. M. Human hepatic microsomal thiol methyltransferase. Assay conditions, biochemical properties, and correlation studies. Drug Metab Dispos. 1992 Mar-Apr;20(2):247–255. [PubMed] [Google Scholar]
  3. Keith R. A., Abraham R. T., Pazmiño P., Weinshilboum R. M. Correlation of low and high affinity thiol methyltransferase and phenol methyltransferase activities in human erythrocyte membranes. Clin Chim Acta. 1983 Jul 15;131(3):257–272. doi: 10.1016/0009-8981(83)90095-5. [DOI] [PubMed] [Google Scholar]
  4. Keith R. A., Jardine I., Kerremans A., Weinshilboum R. M. Human erythrocyte membrane thiol methyltransferase. S-methylation of captopril, N-acetylcysteine, and 7 alpha-thio-spirolactone. Drug Metab Dispos. 1984 Nov-Dec;12(6):717–724. [PubMed] [Google Scholar]
  5. 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]
  6. Macfarlane G. T., Gibson G. R., Cummings J. H. Comparison of fermentation reactions in different regions of the human colon. J Appl Bacteriol. 1992 Jan;72(1):57–64. doi: 10.1111/j.1365-2672.1992.tb04882.x. [DOI] [PubMed] [Google Scholar]
  7. Pacifici G. M., Romiti P., Santerini S., Giuliani L. S-methyltransferases in human intestine: differential distribution of the microsomal thiol methyltransferase and cytosolic thiopurine methyltransferase along the human bowel. Xenobiotica. 1993 Jun;23(6):671–679. doi: 10.3109/00498259309059404. [DOI] [PubMed] [Google Scholar]
  8. Pacifici G. M., Santerini S., Giuliani L., Rane A. Thiol methyltransferase in humans: development and tissue distribution. Dev Pharmacol Ther. 1991;17(1-2):8–15. doi: 10.1159/000457494. [DOI] [PubMed] [Google Scholar]
  9. Pazmiño P. A., Weinshilboum R. M. Human erythrocyte phenol O-methyltransferase: radiochemical microassay and biochemical properties. Clin Chim Acta. 1978 Oct 16;89(2):317–329. doi: 10.1016/0009-8981(78)90331-5. [DOI] [PubMed] [Google Scholar]
  10. Roediger W. E., Duncan A., Kapaniris O., Millard S. Reducing sulfur compounds of the colon impair colonocyte nutrition: implications for ulcerative colitis. Gastroenterology. 1993 Mar;104(3):802–809. doi: 10.1016/0016-5085(93)91016-b. [DOI] [PubMed] [Google Scholar]
  11. Roediger W. E., Truelove S. C. Method of preparing isolated colonic epithelial cells (colonocytes) for metabolic studies. Gut. 1979 Jun;20(6):484–488. doi: 10.1136/gut.20.6.484. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Waring R. H., Steventon G. B., Sturman S. G., Heafield M. T., Smith M. C., Williams A. C. S-methylation in motorneuron disease and Parkinson's disease. Lancet. 1989 Aug 12;2(8659):356–357. doi: 10.1016/s0140-6736(89)90538-2. [DOI] [PubMed] [Google Scholar]
  13. Weinshilboum R. M., Sladek S., Klumpp S. Human erythrocyte thiol methyltransferase: radiochemical microassay and biochemical properties. Clin Chim Acta. 1979 Sep 15;97(1):59–71. doi: 10.1016/0009-8981(79)90025-1. [DOI] [PubMed] [Google Scholar]
  14. Weisiger R. A., Pinkus L. M., Jakoby W. B. Thiol S-methyltransferase: suggested role in detoxication of intestinal hydrogen sulfide. Biochem Pharmacol. 1980 Oct 15;29(20):2885–2887. doi: 10.1016/0006-2952(80)90029-5. [DOI] [PubMed] [Google Scholar]

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