N-Acetylcysteine is an effective analog of glutathione in reactions with reactive oxygen species

The kinetic characteristics of the interaction of N-acetylcysteine (ASH) with reactive oxygen species (ROS), peroxyl radicals and hydrogen peroxide were determined. It was found that in terms of activity ASH in these reactions is similar to glutathione GSH, the main endogenous bioantioxidant. The kinetics of heat release in the interaction of GSH and ASH with H(2)O(2) was studied for the first time by isothermal calorimetry. It is shown that the kinetic curves of heat release and changes in specific heat release rates practically coincide for both thiols taken in the stoichiometric ratio in the known reaction 2 TSH + H(2)O(2) → TSST + 2 H(2)O. This indicates the relative autonomy of the S–H and S–S bonds in thiols and disulfides, which are not affected by other groups in the molecule. At pH<7, ASH, like GSH, interacts with H(2)O(2) to form thiyl radicals, which initiate thiol-ene reactions with unsaturated phenol resveratrol. Under the same conditions, ASH ensures nearly the same radical initiation rates as GSH, and thiyl radicals from ASH are close in activity to GS(•) in chain propagation reactions.