[Electron spin resonance studies on inhibiting methemoglobin in erythrocyte with exogenous ascorbic acid]

Research on inhibiting the methemoglobin (MetHb) in erythrocyte by means of exogenous ascorbic acid is helpful to elucidating whether exogenous antioxidant inhibits the oxidative denaturation of hemoglobin when the erythrocyte does not inhibit such denaturation with its own antioxidation system. Using electron spin resonance (ESR) technique, we have studied the oxidative denaturation of hemoglobin and the inhibition of MetHb in erythrocyte with the exogenous ascorbic acid. The results indicate that there is the ESR absorption of high spin MetHb (g = 6) at the 5th, 35th and 90th min after the blood was mixed with NaNO2. The ESR absorption of high spin MetHb increases with time. Yet, in the case where the blood was mixed with exogenous ascorbic acid in advance, the ESR absortpion of high spin MetHb (g = 6) only appears at the 35th min among the ESR measures at the 5th, 35th, and 90th min after the blood was mixed with NaNO2. These findings suggest that exogenous antioxidant can inhibit the oxidative denaturation of hemoglobin when the erythrocyte does not inhibit such dematuration with its own antioxidation system.