[Electron paramagnetic resonance study of the products of the reaction between nitrogen oxides and several organic...

A method of electron paramagnetic resonance was applied to the study of a possibility of paramagnetic centres formation in the nitrogen oxide reaction with saturated and unsaturated fatty acids and aromatic amino acids. Several paramagnetic centres are formed in interaction of NO2 with oleic acid at 20 degrees C. Saturated fatty acids formed no paramagnetic centres in the reaction with NO2. NO formed no paramagnetic centres not only with butyric, palmitic, and stearic acids, but also with oleic acid. The capacity of NO2 to form paramagentic centres with tyrosine in its saturated solution was revealed. In case of interaction between NO and NO2 with saturated phenylalanine and tryptophane solutions no formation of paramagnetic centres was observed. It is suggested that unsaturated fatty acids and tyrosine remnants of the membrane lipoprotein complexes could serve as peculiar targets with which NO2 interacted, and that formation of paramagnetic centres in the NO2 reaction with the mentioned substances was the primary act of the membrane damage.