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The cytosolic subunit p67 phox of the NADPH‐oxidase complex does not bind NADPH
Author(s) -
Baciou Laura,
Erard Marie,
Dagher Marie-Claire,
Bizouarn Tania
Publication year - 2009
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2009.09.011
Subject(s) - nadph oxidase , cytosol , protein subunit , superoxide , chemistry , enzyme , biochemistry , nadph dehydrogenase , oxidase test , gene , nitric oxide synthase
The NADPH‐oxidase of phagocytic cells is a multicomponent enzyme that generates superoxide. It comprises a membrane flavocytochrome b 558 and four cytosolic proteins; p67 phox , p47 phox , p40 phox and Rac. The NADPH‐binding site of this complex was shown to be located on the flavocytochrome b 558 . However, a number of studies have suggested the presence of another site on the p67 phox subunit which is the key activating component. Using several approaches like tryptophan quenching fluorescence measurement, inhibition by 2′,3′‐dialdehyde NADPH, and free/bound NADPH concentration measurements, we demonstrate that no NADPH binds on p67 phox , thus definitively solving the controversy on the number and location of the NADPH‐binding sites on this complex.