Analysis of paramagnetic intermediates at the reaction of hemoglobin with nitrite using EPR

The autocatalytic oxidation of hemoglobin by nitrite was analysed. It was shown that the obtained paramagnetic species have a strong temperature dependence. The time of annihilation of these species decreases about 4 times in the temperature region between 10 degrees C and 30 degrees C, whereas the time of formation decreases only 1.7 times. These data explain the strange temperature dependence of the formation of methemoglobin by nitrite and support the assumption that the short-lived radical is localized on the hemoglobin molecule.