What question did this study set out to answer?

To determine whether inducible macrophage nitric oxide synthase functions as a cytochrome P-450 type hemoprotein.

July 1, 1992Biochemistry

Nitric oxide synthase is a cytochrome P-450 type hemoprotein

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Authors

KWKimberly A. WhiteNational Institutes of Health MMMichael A. MarlettaQB3

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Implication

Biochemical analysis demonstrates that nitric oxide synthase is a cytochrome P-450 hemoprotein in mammalian tissues, revealing the first self-sufficient soluble eukaryotic P-450 enzyme.

Key Points

To determine whether inducible macrophage nitric oxide synthase functions as a cytochrome P-450 type hemoprotein.
Purified inducible macrophage nitric oxide synthase and performed pyridine hemochrome assays to characterize bound heme.
Measured optical absorbance of reduced carbon monoxide difference spectra and assayed inhibition of L-arginine oxidation using an 80%/20% carbon monoxide/oxygen gas mixture.
Assessed carbon monoxide sensitivity in partially purified nitric oxide synthase isolated from rat cerebellum.
Pyridine hemochrome assay identified bound protoporphyrin IX heme, with the reduced carbon monoxide difference spectrum showing a characteristic absorbance peak at 447 nm.
An 80%/20% carbon monoxide to oxygen atmosphere inhibited nitric oxide synthase activity by 73% to 79%, indicating direct catalytic participation of the heme iron in L-arginine oxidation.
Enzyme activity in rat cerebellar extracts was also inhibited by carbon monoxide, suggesting that neuronal isoforms also operate as cytochrome P-450 hemoproteins.

Cite This Study

White et al. (1992) studied this question.

synapsesocial.com/papers/6a7068afe36a167817e22fa7 https://doi.org/10.1021/bi00144a001

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Implication

Biochemical analysis demonstrates that nitric oxide synthase is a cytochrome P-450 hemoprotein in mammalian tissues, revealing the first self-sufficient soluble eukaryotic P-450 enzyme.

Nitric oxide synthase is a cytochrome P-450 type hemoprotein

Discussion

Member takes

Implication

Key Points

Cite This Study

Nitric oxide synthase is a cytochrome P-450 type hemoprotein

Discussion

Member takes

Implication

Key Points

Cite This Study

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