methemoglobin (redirected from methemoglobin reductase pathway)

methemoglobin /met·he·mo·glo·bin/ (met-he´mo-glo″bin) a hematogenous pigment formed from hemoglobin by oxidation of the iron atom from the ferrous to the ferric state. A small amount is found in the blood normally, but injury or toxic agents convert a larger proportion of hemoglobin into methemoglobin, which does not function as an oxygen carrier.

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met·he·mo·glo·bin (mt-hm-glbn)

n. Abbr. metHb

A brownish-red crystalline organic compound formed in the blood when hemoglobin is oxidated either by decomposition of the blood or by the action of various oxidizing drugs or toxic agents. It contains iron in the ferric state and cannot function as an oxygen carrier.

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Methemoglobin

A compound formed from hemoglobin by oxidation.

Mentioned in: Nephrotoxic Injury

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methemoglobin

[met′hēməglō′bin, met·he′məglō′bin]

a form of hemoglobin in which the iron component has been oxidized from the ferrous to the ferric state. Methemoglobin cannot carry oxygen. It is a product of various oxidative reactions that constitute normal metabolic activity and is normally present in only trace amounts (about 1%) in the blood. Maintenance of levels occurs by an active enzymatic reducing capability, the nicotinamide-adenine dinucleotide-methemoglobin reductase system present in normal red blood cells. Also spelled methaemoglobin. See also hemoglobin.

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methemoglobin

a compound formed from hemoglobin by oxidation of the iron atom from the ferrous to the ferric state. A small amount of methemoglobin is normally present in the blood, but injury or toxic agents convert a larger proportion of hemoglobin into methemoglobin, which does not function as an oxygen carrier. See also hemoglobin.

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methemoglobin reductase pathway

an intraerythrocyte enzyme system that maintains hemoglobin in a reduced state. A deficiency of the enzyme, resulting in the formation of methemoglobinemia with insufficient oxygenation of the blood, occurs in the dog.