Abstract
Inorganic pyrophosphate is found to inhibit the ferredoxin-dependent photoreduction of NADP by isolated chloroplasts. The reduction of ferricyanide is not inhibited, nor is the activity of photosystem 1 as measured with methyl viologen as the electron acceptor. All other ferredoxin-depended reactions are inhibited, such as cytochrome c photoreduction and the reaction sequence: NADPH →Flavoprotein→ferredoxin→cytochrome c. The inhibition by pyrophosphate is, in all cases, competitive with ferredoxin and independent of NADP concentration. Pyrophosphate inhibition of the formation of the ferredoxin-flavoprotein complex is demonstrated spectrophotometrically.
Full text
PDF
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Cockburn W., Baldry C. W., Walker D. A. Oxygen evolution by isolated chloroplasts with carbon dioxide as the hydrogen acceptor. A requirement for orthophosphate or pyrophosphate. Biochim Biophys Acta. 1967 May 9;131(3):594–596. doi: 10.1016/0005-2728(67)90022-9. [DOI] [PubMed] [Google Scholar]
- Cockburn W., Baldry C. W., Walker D. A. Some effects of inorganic phosphate on O2 evolution by isolated chloroplasts. Biochim Biophys Acta. 1967;143(3):614–624. doi: 10.1016/0005-2728(67)90067-9. [DOI] [PubMed] [Google Scholar]
- FORTI G., JAGENDORF A. T. Photosynthetic phosphorylation in the absence of redox dyes: oxygen and ascorbate effects. Biochim Biophys Acta. 1961 Dec 9;54:322–330. doi: 10.1016/0006-3002(61)90372-9. [DOI] [PubMed] [Google Scholar]
- Forti G., Sturani E. On the structure and function of reduced nicotinamide adenine dinucleotide phosphate-cytochrome f reductase of spinach chloroplasts. Eur J Biochem. 1968 Feb;3(4):461–472. doi: 10.1111/j.1432-1033.1967.tb19553.x. [DOI] [PubMed] [Google Scholar]
- Forti G. The stoichiometry of NADP dependent photosynthetic phosphorylation. Biochem Biophys Res Commun. 1968 Sep 30;32(6):1020–1024. doi: 10.1016/0006-291x(68)90131-9. [DOI] [PubMed] [Google Scholar]
- Foust G. P., Mayhew S. G., Massey V. Complex formation between ferredoxin triphosphopyridine nucleotide reductase and electron transfer proteins. J Biol Chem. 1969 Feb 10;244(3):964–970. [PubMed] [Google Scholar]
- Jensen R. G., Bassham J. A. Photosynthesis by isolated chloroplasts. II. Effects of addition of cofactors and intermediate compounds. Biochim Biophys Acta. 1968 Jan 15;153(1):219–226. doi: 10.1016/0005-2728(68)90163-1. [DOI] [PubMed] [Google Scholar]