[The spectral and paramagnetic properties of oxyhemoglobin solutions UV-irradiated in the presence of ascorbic acid]

Absorption spectra and ESR of aqueous and aqueous/glyceric solutions of oxyhemoglobin exposed to UV radiation (250-400 nm) at 293 and 77 K in the presence of ascorbic acid have been analyzed. Vitamin C (5 x 10(-5) M) has been shown to exert a photoprotective effect with regard to oxyhemoglobin (2 x 10(-6) M) UV-irradiated with a dose of 0.86 x 10(5) J/m2 at 293 K. The photoprotective effect of ascorbic acid is also displayed after UV irradiation of frozen (77 K) aqueous/glyceric oxyhemoglobin solutions (2.53 x 10(-5) M). It is concluded that ascorbic acid can be a scavenger with respect to active UV-induced particles in protein systems, including O2-. and OH. Proposed is a mode of processes leading to UV inactivation of hemoprotein molecules.