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Old 07-13-2011
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Biochemistry The only reaction in the human body that generates Carbon Monoxide

There is but a single enzyme-catalyzed reaction in the human body known to generate carbon monoxide (CO) as one of its products. Which of the following enzymes represents the one that catalyzes this CO-producing reaction?

(A) biliverdin reductase
(B) coproporphyrinogen oxidase
(C) heme oxygenase
(D) protoporphyrinogen oxidase
(E) uroporphyrinogen decarboxylase
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Old 07-13-2011
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heme oxygenase
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Old 07-13-2011
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C) heme
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Old 07-13-2011
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Correct Answer Heme Oxidase (C)

Heme is oxidized, with the heme ring being opened by the endoplasmic reticulum enzyme, heme oxygenase. The oxidation step requires heme as a substrate, and any hemin (Fe3+) is reduced to heme (Fe2+) prior to oxidation by heme oxygenase. The oxidation occurs on a specific carbon producing the linear tetrapyrrole biliverdin, ferric iron (Fe3+), and CO. This is the only reaction in the body that is known to produce CO.

Heme ->>Biliverdin ->> Bilirubin transformation
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