On N-acetylcysteine. Part II. Oxidation of N-acetylcysteine by hydrogen peroxide: kinetic study of the overall process

Abstract

ZOHREH A B E D~E H ,JLJL ARROUB, and MOMQUE GARD~S-ALBERT. Can. J. Chem. 72,2102Chem. 72, (1994.The oxidation kinetics of N-acetylcysteine (RSH) by hydrogen eroxide has been studied at neutral pH at different concentration ratios from 0.2 to 20 (4 x lo4 rnol L-I B [RSH], r 2 x 10-' mol L-I, lo4 rnol L-I 5 [H202], 5 lo-' rnol L-I). In all the cases studied, N-acetylcystine (RSSR) is the only oxidized product formed. Our kinetic data have focused on the importance of the concentration ratio to reach the stoichiometric oxidation of N-acetylcysteine by hydrogen peroxide. Indeed non-stoichiometric oxidation of RSH occurs at relatively low concentration ratios (R < 2.5) whereas stoichiometric oxidation is observed when R > 2.5. Moreover, it has been shown that in the first minutes of the reaction there is the formation of a complex between RSH and H202, the stoichiometry of the complex being RSH concentration-dependent for a given R (R > 2

Vibrational spectroscopic study of glutathione complexation in aqueous solutions

“…As already observed on RSSR spectra with respect to RSH, 13 all the bands for GSSG are much broader than for GSH (Fig. 5).…”

“…A similar study has been carried out in the case of N-acetylcysteine (RSH). [13][14][15] The peptidic bonds CONH have various vibrational modes, infrared or Raman active, and a detailed analysis was done in a previous article.…”

Quinone and oxyradical scavenging properties of N-acetylcysteine prevent dopamine mediated inhibition of Na+, K+-ATPase and mitochondrial electron transport chain activity in rat brain: Implications in the neuroprotective therapy of Parkinson's disease

“…N-acetylcysteine is known to react with several members of reactive oxygen species including H 2 O 2 and the kinetics of N-acetylcysteine oxidation by H 2 O 2 has also been studied in much detail [28,29]. Our data are in conformity with earlier studies and indicate that N-acetylcysteine is a powerful scavenger of H 2 O 2 (Table I).…”

Kinetics and Mechanism of the Reaction of Cysteine and Hydrogen Peroxide in Aqueous Solution

“…Several studies of the reaction between various low molecular weight thiols (e.g., cysteine, N‐acetylcysteine, glutathione, and others) and hydrogen peroxide (H 2 O 2 ) or other peroxides (e.g., benzoyl peroxide, lipid hydroperoxides, etc.) have been reported, but there does not appear to be a consensus as to the reaction products formed under various conditions,10,14,15,39–42 the mechanism(s) by which these products form,10,14,15,41–44 or the rate constants for various reaction steps.…”