Anaerobic metabolism reaction system

Once simple sulfides (thioethers) enter the systemic circulation, they are rapidly oxidized to sulfoxides and, depending on the structure of the thioether, may be further oxidized to sulfones. Aliphatic thioethers yield mixtures of sulfoxide and sulfone urinary metabolites (Damani, 1987). Enzymes of the cytochrome P450 superfamily and flavin-containing monooxygenases catalyse the oxidation of thioethers to sulfoxides (Renwick, 1989). Oxidation of sulfoxides to the corresponding sulfones occurs both in tissues and in aerobic microorganisms and is an irreversible metabolic reaction in mammals (Damani, 1987). Sulfoxides can also be metabolized back to the thioether by thioredoxin and its reductase and by the gut microflora in the anaerobic environment of the lower bowel (Lee Renwick, 1995). 

The META system (291-293) is an expert system, based on well-established sources, for predicting the sites of potential enzymatic attack and the metabolites formed by metabolic transformations. The program uses dictionaries of biotransformation operators, which are created by experts to represent known metabolic paths. Currently, META can be combined with one of the following dictionaries mammalian metabolism, aerobic biodegradation, anaerobic biodegradation, and metabolic transformation reactions (291). 

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