Genetic aspects of the polymodally distributed sulphoxidation of S‐ carboxymethyl‐L‐cysteine in man.

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

“…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. The S-oxides are seen as creamy-yellow spots on a pink background [16] and are very distinct from the yellow spots produced by certain disulphide containing compounds.…”

“…In 1984, a genetic polymorphism was describe in which the affected individuals were only able to form small quantities of S-oxide metabolites (28-42 % of a Caucasian population, [16]). While this observation is of academic interest, further work was to link the S-oxidation of SCMC to adverse drug reactions in rheumatoid arthritis (RA) patients and disease aetiology in five de, generative diseases [17].…”

Enzyme kinetic and molecular modelling studies of sulphur-containing substrates of phenylalanine 4-monooxygenase

“…However, it is clear that while some patients respond very well to the mucolytic drugs others show little or no benefit. This observed variation in response to these mucolytic agents could be linked to the human genetic polymorphism in the S-oxidation of SCMC in man [5]. The major urinary metabolites of SCMC in man are the S-oxides (SCMC S-oxide, SMC S-oxide, N-acetyl SMC S-oxide, N-acetyl-SCMC S-oxide and thiodiglycolic acid S-oxide).…”

The sulphoxidation of S-carboxymethyl-L-cysteine in COPD

“…Thus, a night-time intake of the drug should be more beneficial to the patient than daytime administration. However, this diurnal variation in metabolism (deactivation) is overlaid on an underlying genetic polymorphism that gives the patient population a spread of S-carboxymethyl-L-cysteine sulphoxidation capacities [7] ( fig. 1).…”