Document Detail


Measurement of S-methylcysteine and S-methyl-mercapturic acid in human urine by alkyl-chloroformate extractive derivatization and isotope-dilution gas chromatography-mass spectrometry.
MedLine Citation:
PMID:  21110385     Owner:  NLM     Status:  In-Data-Review    
Abstract/OtherAbstract:
S-methylcysteine (SMC) is a minor amino acid naturally excreted in human urine, a protective agent against oxidative stress and a biotransformation product of the fumigant biocide methyl bromide and of nicotine. A metabolic source of SMC is catabolism of the repair catalytic protein MGMT (EC 2.1.1.37), which specifically removes the methyl group from the modified DNA nucleotide O-6-methyl-guanine to revert the normal GC base pairing. To assess the value of SMC and of S-methylmercapturic acid (SMMA) as candidate biomarkers of proliferative phenomena, a sensitive analytical method by GC-MS was applied in a pilot study of healthy subjects to assess their urinary elimination and the intra- and inter-individual variability. Extractive alkylation with butylchloroformate-n-butanol-pyridine (Husek technique) was employed for sample derivatization and isotope dilution GC-MS with S-[CD(3) ]-SMC and -SMMA was applied for specific and sensitive detection. To resolve the target analytes from the main coeluting interferents in the derivatized urine extract a medium-polarity stationary phase was employed. SMMA was not detected in the morning urine of three healthy fertile-age women followed for one month above the minimum detectable level of approx. 500 µg/L while SMC concentrations were in the 0.02-0.7 µg/mL range (n = 61) with large inter-day and inter-individual variations. In a young healthy male urine samples taken throughout a few days yielded concentrations in the same 90-810 µg/L range (n = 11). These preliminary results points at SMC as a candidate biomarker for the study of methylation turnover in several biochemical processes. Copyright © 2010 John Wiley & Sons, Ltd.
Authors:
Federico M Rubino; Marco Pitton; Daniela Di Fabio; Giuseppe Meroni; Enzo Santaniello; Enrico Caneva; Marco Pappini; Antonio Colombi
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Biomedical chromatography : BMC     Volume:  25     ISSN:  1099-0801     ISO Abbreviation:  Biomed. Chromatogr.     Publication Date:  2011 Mar 
Date Detail:
Created Date:  2011-02-15     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8610241     Medline TA:  Biomed Chromatogr     Country:  England    
Other Details:
Languages:  eng     Pagination:  330-43     Citation Subset:  IM    
Copyright Information:
Copyright © 2010 John Wiley & Sons, Ltd.
Affiliation:
LaTMA Laboratory for Analytical Toxicology and Metabonomics, Department of Medicine, Surgery and Dental Sciences, Università degli Studi di Milano at 'Ospedale San Paolo', v. A di Rudinì 8, Milano I-20142, Italy. Federico.Rubino@unimi.it.
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