Search results for "Photophosphorylation"
showing 5 items of 5 documents
The Effect of Light Intensity During Growth of Sinapis alba on the Electron-Transport and the Noncyclic Photophosphorylation
1975
The photosynthetic rate of Sinapis alba can be modified over a wide range by the light intensity during growth. Our present results indicate that there exist regulatory mechanisms in the field of photosynthetic primary reactions. We compared the effect of different light intensities during growth of Sinapis plants on the concentrations of soluble proteins, manganese and lipophilic plastid quinones, the electron flow from water to ferricyanide and noncyclic phosphorylation. We further determined the light dependence curves for the uncoupled electron transport with ferricyanide as electron acceptor and methylammonium-chloride as an uncoupler of photophosphorylation.
Conversion of the Ca2+-ATPase from Rhodospirillum rubrum into a Mg2+-dependent enzyme by 1,N6-etheno ATP
1980
Nucleoside triphosphate hydrolysis of R.rubrum ATPase complexes can be changed from Ca2+-dependence to Mg2+-dependence by replacing ATP with 1,N6-etheno ATP. Four ATPase complexes which have been prepared by different procedures hydrolyze ATP and 1,N6-etheno ATP at different rates in dependence on the added metal ions. These differences allow an easy distinction of the various enzyme forms.
Cyclic and noncyclic photophosphorylation during the ontogenesis of high-light and low-light leaves of Sinapis alba.
1981
Noncyclic electron transport to ferricyanide and photophosphorylation as well as the methylviologen mediated aerobic and anaerobic photophosphorylation with dichlorophenolindophenol-ascorbate as the electron donor of photosystem I were measured during the development of high-light and low-light adapted leaves of Sinapis alba. Anaerobic methylviologen-catalyzed phosphorylation is more than twice as high as aerobic phosphorylation. The difference between the rates of aerobic and anaerobic phosphorylation is sensitive to dibromothymoquinone. Thus, under anaerobic conditions, methylviologen mediates a cyclic phosphorylation including plastoquinone. All photochemical activities of high-light chl…
Light-induced proton slip and proton leak at the thylakoid membrane
2005
A treatment of leaves of Spinacia oleracea L. with light or with the thiol reagent dithiothreitol in the dark led to partly uncoupled thylakoids. After induction in intact leaves, the partial uncoupling was irreversible at the level of isolated thylakoids. We distinguish between uncoupling by proton slip, which means a decrease of the H+/e(-) -ratio due to less efficient proton pumping, and proton leak as defined by enhanced kinetics of proton efflux. Proton slip and proton leak made about equal contributions to the total uncoupling. The enhanced proton efflux kinetics corresponded to reduction of subunit CF1-gamma of the ATP synthase as shown by fluorescence labeling of thylakoid proteins …
Correlative Analysis of the Photosynthetic Capacity and Different Components of the Photosynthetic Apparatus
1984
The majority of higher plants is able to adapt to the ecological factor light in a wide range. Depending on the light intensity and the light quality during growth, plant with an equal genotype develop into so-called low light and high light forms. The photosynthetic adaptation to different light conditions involves complex, balanced changes of many leaf features. The changes of physiological factors of photosynthesis includes differences in the CO2 conductance, in the Calvin cycle enzymes, the capacity of electron transport, the photophosphorylation and the pigments (Boardman, 1977; Wild, 1979; Bjorkman, 1981; Lichtenthaler et al., 1981). The adaptation of individual plants or leaves to lo…