Involvement of Superoxide Radicals in the Formation of Methemoglobin from Oxyhemoglobin : Inhibition of Superoxide Dismutase by Diethyldithiocarbamate

概要

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Diethyldithiocarbamate (DDC), a copper chelate agent, was used to examine a possible participation of superoxide radicals (O_2-) in the formation of methemoglobin (metHb) under the O_2- generating system of photoactivated riboflavin. Superoxide dismutase in the lysate from DDC-injected rats was inhibited to 93% and catalase remained unchange, however, the formation of metHb was scarcely observed. In the experiments in vitro, superoxide dismutase was completely inhibited by the pretreatment with DDC above 3 mM whereas catalase was partially inhibited. In this case, the formation of metHb was accelerated with increase of DDC concentration. Addition of catalase to the dialyzed lysate resulted in the inhibition of formation of metHb to almost the same level as that in the normal lysate. Superoxide dismutase alone, however, caused a slight increase in the rate of formation of metHb, indicating that catalase but not superoxide dismutase has protective ability to the formation of metHb by O_2-. From these results, O_2-appears to be the source of hydrogen peroxide which accounts for most the observed metHb formation.
公益社団法人日本薬学会の論文
1978-04-25