The formation of “hydrogen peroxide” in the reaction of oxyhemoglobin with methemoglobin-forming agents

Abstract

1. 1. Comparisons were made among the reactions of phenylhydrazine, hydrazine, phenylhydroxylamine, and hydroxylamine with oxyhemoglobin and methemoglobin, especially with regard to the production of H 2O 2 or equivalent free radicals, methemoglobin production and reduction, and verdoglobin formation. 2. 2. Phenylhydrazine and phenylhydroxylamine were found to react with oxyhemoglobin and methemoglobin at a much faster rate than hydrazine or hydroxylamine. 3. 3. H 2O 2 or free radicals were produced rapidly by all the reducing agents mentioned, except hydrazine, when reacting with oxyhemoglobin, but the latter reacted too slowly to give a measurable amount of H 2O 2 or free radicals. 4. 4. Phenylhydroxylamine produced no measurable verdoglobin, although evidence is presented for free-radical production in this case. 5. 5. Possible mechanisms for verdoglobin production are discussed in light of the failure of phenylhydroxylamine to produce the green pigment.