THE MECHANISM OF INTERACTION OF CARNOSINE WITH SUPEROXIDE RADICALS INWATER SOLUTIONS

The antiradical activity and the radiation stability of carnosine in w ater solutions was studied by the pulse radiolysis technique with spec trophotometric registration of absorbance. The transient spectra were recorded in the range 245-670 nm during 2 . 10(-6)-20 s after the puls e using a flow system for continuous change and saturation of the samp les by different gases. Also, the spectra of the stable products of ra diolysis were studied. The results obtained give evidence that carnosi ne in water solutions in the presence of oxygen behaves like a multifu nctional antioxidant. Even at low concentrations, dipeptide forms a ch arge-transfer complex (Car ... O2-., lambda(max) = 265 nm) with the su peroxide radical which changes the reactivity of O2-.. The absorbance band of the complex was shifted towards lower energy as compared to su peroxide radical lambda(max) = 255 nm). The interaction of carnosine w ith OH-radicals proceeding at very high rate and resulting in the form ation of a stable product suggested another type of dipeptide activity . The kinetic mechanism of the interaction of carnosine with products of radiolysis of water in aerobic conditions is discussed.