Document Detail


Sequential methylation of 2-mercaptoethanol to the dimethyl sulfonium ion, 2-(dimethylthio)ethanol, in vivo and in vitro.
MedLine Citation:
PMID:  8093089     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Thioether methyltransferase (S-adenosyl-L-methionine: thioether S-methyltransferase; EC 2.1.1.96) catalyzes the methylation of X in compounds of the type R-X-R'(X = S, Se, Te), yielding a methyl onium ion. Previous results using mice have demonstrated a role for thioether methyltransferase in the conversion and clearance of thioethers by methylation to more water-soluble methyl sulfonium ions suitable for excretion in the urine. A potential major physiological source of thiethers is reactions catalyzed by microsomal thiol methyltransferase (S-adenosyl-L-methionine: thiol S-methyltransferase; EC 2.1.1.9), which has been shown to methylate a diverse range of aliphatic sulfhydryl compounds. This study provides evidence for the sequential methylation of the aliphatic thiol, 2-mercaptoethanol, first to the methyl thioether, 2-(methylthio)ethanol, by thiol methyltransferase followed by methylation of this methyl thioeter to the dimethyl sulfonium ion, 2-(-dimethylthio)ethanol, by thioether methyltransferase. This sequence of reactions was demonstrated in vivo by injecting mice i.p. with radioactive 2-mercaptoethanol and analyzing the labeled methylated products, 2-(methylthio)ethanol and 2(dimethylthio)ethanol, in the urine by HPLC. In addition, the system converting 2-mercaptoethanol to 2-(dimethylthio)ethanol was reconstituted in vitro using solubilized mouse liver microsomes as a source of thiol methyltransferase and purified thioether methyltransferase from mouse lung. The results of these in vivo and in vitro studies established the sequential methylation of 2-mercaptoethanol by these two enzymes.
Authors:
S L Carrithers; J L Hoffman
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Biochemical pharmacology     Volume:  48     ISSN:  0006-2952     ISO Abbreviation:  Biochem. Pharmacol.     Publication Date:  1994 Aug 
Date Detail:
Created Date:  1994-10-19     Completed Date:  1994-10-19     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0101032     Medline TA:  Biochem Pharmacol     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  1017-24     Citation Subset:  IM    
Affiliation:
Department of Medicine, Thomas Jefferson University, Philadelphia, PA 19107.
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MeSH Terms
Descriptor/Qualifier:
Animals
Choline / analogs & derivatives*,  metabolism,  urine
Chromatography, High Pressure Liquid
Female
Mercaptoethanol / metabolism*
Methylation
Methyltransferases / metabolism
Mice
Grant Support
ID/Acronym/Agency:
ES4887/ES/NIEHS NIH HHS
Chemical
Reg. No./Substance:
60-24-2/Mercaptoethanol; 62-49-7/Choline; 7629-91-6/sulfocholine; EC 2.1.1.-/Methyltransferases; EC 2.1.1.-/S-adenosyl methionine thioether S-methyltransferase; EC 2.1.1.9/thiol S-methyltransferase

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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