Biochemical studies of toxic agents. 15. The biosynthesis of ethylmercapturic acid sulphoxide

Abstract

The oxidation of a number of thio ethers to Soxides (sulphoxidation) has been observed in biological systems. Compounds metabolized by mammals to the sulphoxide include chlorpromazine (Salzman & Brodie, 1956), 1,2-diphenyl-4-(phenylthioethyl)pyrazolidine-3,5-dione (Bums et al. 1957) and promazine (Walkenstein & Seifter, 1959). The oxidation occurs in microorganisms: (-)-biotin sulphoxide is produced by A8pergillu8 niger (Wright, Cresson, Valiant, Wolf & Folkers, 1954) and 17flacetoxy-7oc-methylthioandrost-4-en-3-one is converted by Catonectria decora into 17fi-hydroxy-7ctmethylsulphinylandrost-4-en-3-one (Holmlund et al. 1962). Several examples of the occurrence of sulphoxides in plants are known. They are principally S-alkyl-L-cysteine S-oxides, their derivatives and w-methylsulphinylalkyl isothiocyanate glucosides, and they have been reviewed recently by Virtanen (1962). The sulphoxidation of 4,4'-diaminodiphenyl sulphide has been observed in vitro with a preparation of guinea-pig-liver microsomes which required 1964

The Role of Glutathione and Glutathione S‐Transferases in Mercapturic Acid Biosynthesis

“…Hydroxyalkylmercapturic acids could also be formed by hydroxylation of the corresponding alkylmercapturic acid or precursor before excretion, as rat liver slices convert S-butylcysteine and butylmercapturic acid to hydroxyalkylmercapturic acids (James, Jeff ery, Waring and Wood, 1968 Hydroxyalkylmercapturic acid formation is restricted to alkyl halides containing more than two carbon atoms since these hydroxyalkylmercapturic acids have not been reported as metabolites of iodomethane (Barnsley and Young, 1965) or bromoethane (Thomson et al, 1963). Bromoethane and 1-bromopropane (23) are also partly metabolized to the alkylmercapturic acid sulfoxide (Barnsley, Thomson, and Young, 1964;Barnsley, Grenby, and Young, 1966). The significance of this is unknown, but several S-alkyl-L-cysteine sulfoxides occur naturally in plants, e.g., alliin (28) in garlic (Virtanen, 1962).…”

The sulfoxide of thymosin β4 almost lacks the polymerization‐inhibiting capacity for actin

“…In animals [30,311 and plants [32, 331 sulfoxides can be formed from thioethers under physiological conditions. Given the fact that the Tp4 sulfoxide isolated together with native Tp4 was not a product of autoxidation but of natural origin, the possibility exists, that Tp4 sulfoxide is part of a regulatory system that governs filament formation.…”

A methodological and metabolite identification study of the metabolism of S-carboxymethyl-L-cysteine in man

“…Blank urine samples and blank urine samples containing reference compounds of known concentration were added to each chromatogram as standards. The development time of the paper was 16 hours at room temperature and the sulphide, disulphide and S-oxide compounds were visualised by the modified chloroplatinate reaction employing, 10 %, w/v chloroplatinic acid (4.0 mL), 1 M potassium iodide (0.25 mL), 6 M HC1 (0.4 mL) and acetone (40 mL) per sheet of Whatman 3MM paper as modified by Barnsley et al [32]. Sulphide and disulphide containing compounds appeared within 30 minutes of dipping the chromatograms as white or yellow spots on a pink background but S-oxide metabolite visualisation required 48-72 hours in the dark (this prevents bleaching of the chromatogram) with a maximum response being seen at 72 hours.…”