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Updated: Aug 18, 2026

Chemiluminescence-based Assays for Detection of Nitric Oxide and its Derivatives from Autoxidation and Nitrosated Compounds
Published on: February 16, 2022
Proposed mechanism of nitrite-induced methemoglobinemia
1Russian State Medical University, 117437 Moscow, Russia. nmc@tsinet.ru
Abstract:
A scheme of development of nitrite-induced oxyhemoglobin oxidation in erythrocytes based on the analysis of experimental data is proposed. It was found that, contrary to widespread opinion, direct oxidative-reductive interaction between hemoglobin and nitrite is absent or negligible under physiological conditions. The driving stage of this process is methemoglobin-catalyzed peroxidase oxidation of nitrite. The product of the oxidation (presumably NO2*) directly oxidizes oxyhemoglobin to methemoglobin-peroxide complex without hydrogen peroxide release into the environment. The oxidant itself is reduced to nitrite or oxidized to nitrate as a result of interaction with another NO2* molecule. Thus, the stoichiometry of the process depends on the ratio of rates of these two reactions. Substances that are able to compete with nitrite for peroxidase and therefore to prevent the nitrite oxidation effectively protect hemoglobin from oxidation. Catalase is not able to destroy methemoglobin-peroxide complexes, but it can prevent their production in the course of interaction of methemoglobin and free peroxide by destroying the latter.
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