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. 1987 Apr;83(4):965–969. doi: 10.1104/pp.83.4.965

Regulation of Cyclic Photophosphorylation during Ferredoxin-Mediated Electron Transport 1

Effect of DCMU and the NADPH/NADP+ Ratio

Jonathon P Hosler 1,2, Charles F Yocum 1
PMCID: PMC1056483  PMID: 16665372

Abstract

Addition of ferredoxin to isolated thylakoid membranes reconstitutes electron transport from water to NADP and to O2 (the Mehler reaction). This electron flow is coupled to ATP synthesis, and both cyclic and noncyclic electron transport drive photophosphorylation. Under conditions where the NADPH/NADP+ ratio is varied, the amount of ATP synthesis due to cyclic activity is also varied, as is the amount of cyclic activity which is sensitive to antimycin A. Partial inhibition of photosystem II activity with DCMU (which affects reduction of electron carriers of the interphotosystem chain) also affects the level of cyclic activity. The results of these experiments indicate that two modes of cyclic electron transfer activity, which differ in their antimycin A sensitivity, can operate in the thylakoid membrane. Regulation of these activities can occur at the level of ferredoxin and is governed by the NADPH/NADP ratio.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

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