Inhibition of electron transfer through the cytochromeb-c1complex by nitric oxide in a photodenitrifier,Rhodopseudomonas sphaeroidesforma sp.denitrificans
✍ Scribed by Toshio Satoh
- Publisher
- Springer
- Year
- 1984
- Tongue
- English
- Weight
- 579 KB
- Volume
- 139-139
- Category
- Article
- ISSN
- 0302-8933
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✦ Synopsis
The effects of nitric oxide (NO) on electron transfer were studied with a photodenitrifier, Rhodopseudomonas sphaeroides forma sp. denitr~'cans. NO inhibited the oxidation of cytochrome c induced by continuous illumination in intact cells. NO inhibited the re-reduction of cytochrome c, the slow phase of the carotenoid bandshift, and the oxidation of cytochrome b after a flash illumination, suggesting that NO inhibited the photosynthetic cyclic electron transfer through the cytochrome b-c~ region. NO also inhibited the nitrite (NO~) and NO reductions with succinate as the electron donor in intact cells, but did not inhibit the NO2 and NO reductions in chromatophore membranes with ascorbate and phenazine methosulfate as the electron donors. NO reversibly inhibited the ubiquinol:cytochrome e oxidoreductase of the membranes, suggesting that NO inhibited the electron transfer through the cytochrome bca region and that the cytochrome b-ct complex also was involved in the electron transport in both NO~ and NO reductions. The catalytic site of NO reduction was distinct from the inhibitory site of NO.