Kinetics of Azanone (HNO) Reactions with Thiols: Effect of pH
Renata Smulik-Izydorczyk1, Karolina Dębowska1, Michał Rostkowski1
1Institute of Applied Radiation Chemistry, Lodz University of Technology, Lodz, Poland.
Abstract:
HNO (nitroxyl, IUPAC name azanone) is an electrophilic reactive nitrogen species of growing pharmacological and biological significance. Here, we present data on the pH-dependent kinetics of azanone reactions with the low molecular thiols glutathione and N-acetylcysteine, as well as with important serum proteins: bovine serum albumin and human serum albumin. The competition kinetics method used is based on two parallel HNO reactions: with RSH/RS- or with O2. The results provide evidence that the reaction of azanone with the anionic form of thiols (RS-) is favored over reactions with the protonated form (RSH). The data are supported with quantum mechanical calculations. A comprehensive discussion of the HNO reaction with thiolates is provided.
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