What question did this study set out to answer?

To identify the flavoprotein and NADPH-binding component responsible for electron transfer in the phagocytic NADPH oxidase complex.

June 15, 1992Biochemical JournalOpen Access

Cytochrome b-245 is a flavocytochrome containing FAD and the NADPH-binding site of the microbicidal oxidase of phagocytes

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Authors

ASAnthony W. SegalSoroka Medical Center IWIan WestShropshire Council FWFrans B. WientjesUniversity College London

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Implication

Experimental study demonstrates that cytochrome b-245 contains both FAD and NADPH-binding sites in phagocytes, indicating it forms the core electron-transporting unit of NADPH oxidase.

Key Points

To identify the flavoprotein and NADPH-binding component responsible for electron transfer in the phagocytic NADPH oxidase complex.
Measured membrane haem-to-FAD ratios and FAD content in normal subjects, uninduced HL60 cells, and patients with X-linked or autosomal recessive chronic granulomatous disease (CGD).
Analyzed purified cytochrome b-245 using electron paramagnetic resonance spectroscopy, lipid-mediated reflavination assays, and sequence homology comparisons with ferredoxin-NADP+ reductases.
Employed photoaffinity labeling with phosphorus-32-labeled 2-azido-NADP in normal and mutant CGD cell membranes to detect the NADPH-binding subunit.
Membrane FAD content in cytochrome b-deficient X-linked CGD was approximately one-quarter of normal levels, and purified cytochrome b-245 bound haem and FAD at a 2:1 molar ratio.
Photoaffinity labeling localized the NADPH-binding site specifically to the beta-subunit of cytochrome b-245, which was competitively inhibited by NADP.
Photoaffinity labeling was absent in cells from three X-linked CGD subjects lacking the cytochrome and one subject harboring a Pro-His transposition in the putative NADPH-binding domain.

Cite This Study

Segal et al. (1992) studied this question.

synapsesocial.com/papers/6a700ef48031ec7bb1dc16aa https://doi.org/10.1042/bj2840781

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Implication

Experimental study demonstrates that cytochrome b-245 contains both FAD and NADPH-binding sites in phagocytes, indicating it forms the core electron-transporting unit of NADPH oxidase.

Cytochrome b-245 is a flavocytochrome containing FAD and the NADPH-binding site of the microbicidal oxidase of phagocytes

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Implication

Key Points

Cite This Study

Cytochrome b-245 is a flavocytochrome containing FAD and the NADPH-binding site of the microbicidal oxidase of phagocytes

Discussion

Member takes

Implication

Key Points

Cite This Study

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