Kinetics of Electron Transfer from QAto QBin Photosystem II†

Biochemistry ◽  
2001 ◽  
Vol 40 (39) ◽  
pp. 11912-11922 ◽  
Author(s):  
Rik de Wijn ◽  
Hans J. van Gorkom
Keyword(s):  
Electron Transfer ◽  
Photosystem Ii ◽  
Kinetics Of

Conserved Kinetics at the Reducing Side of Reaction-Center II in Photosynthetic Organisms; Changed Kinetics in Triazine-Resistant Weeds

1990 ◽  
Vol 45 (5) ◽  
pp. 441-445 ◽  
Author(s):  
Marcel A. K. Jansen ◽  
Klaus Pfister
Keyword(s):  
Electron Transfer ◽  
Photosystem Ii ◽  
Decay Time ◽  
D1 Protein ◽  
Structural Variations ◽  
Ecological Fitness ◽  
Photosynthetic Organisms ◽  
Single Turnover ◽  
Functional Factors ◽  
Kinetics Of

The decay of chlorophyll variable fluorescence after a “single turnover” flash is generally assumed to represent the reoxidation of the reduced quinone Qa. We have observed that the kinetics of this decay are very similar in a wide variety of species. Comparing 28 different species, we found an average half decay time of 314 ± 46 μsec. No systematic correlations were found between the decay rate and biochemical or physiological specializations such as C2, C4 or CAM. This indicates that structural as well as functional factors controlling photosystem II electron transfer between Qa and Qb are highly conserved. Apparently, the freedom for natural structural variations in this region is very limited. Triazine resistant plants, characterized by an altered amino acid sequence of the D1 protein, have clearly decreased rates of Qa/Qb electron transfer. We found an average half decay time of 946 ± 100 (isec (5 species). However, this three-fold decrease is much less than previously reported. Therefore, if alterations of photosystem II electron transfer efficiency contributes to an often reported reduction of “ecological fitness”, this contribution is smaller than was hitherto assumed.

Kinetics of Action of Different Photosystem II Herbicides on Thylakoids

1990 ◽  
Vol 45 (5) ◽  
pp. 348-352 ◽  
Author(s):  
Jean-Marc Ducruet ◽  
Sophie Creuzet ◽  
Josiane Viénot
Keyword(s):  
Electron Transfer ◽  
Chlorophyll Fluorescence ◽  
Photosystem Ii ◽  
Temperature Dependent ◽  
Binding Process ◽  
Uracil Derivatives ◽  
Fluorescence Measurements ◽  
Kinetics Of

The kinctics of inhibition of photosystem II electron transfer by different diuron-like herbicides (ureas, triazines, triazinoncs, biscarbamates. uraciles) were studied, mainly by chlorophyll fluorescence measurements. Uracil derivatives and cyanazine, a particular triazinc. were the slowest acting compounds. The half-times of action were strongly temperature-dependent and were of the order of tens of seconds at 5 °C for urea or triazine inhibitors. The role of different limiting steps in the binding process is discussed.

scholarly journals Single entity electrochemistry and the electron transfer kinetics of hydrazine oxidation

Nano Research ◽  
2021 ◽  
Author(s):  
Ruiyang Miao ◽  
Lidong Shao ◽  
Richard G. Compton
Keyword(s):  
Electron Transfer ◽  
Bulk Solution ◽  
Relative Contribution ◽  
Rate Determining Step ◽  
Multistep Process ◽  
Ph Range ◽  
Electro Catalytic Oxidation ◽  
Single Particle Impact ◽  
The Impact ◽  
Kinetics Of

AbstractThe mechanism and kinetics of the electro-catalytic oxidation of hydrazine by graphene oxide platelets randomly decorated with palladium nanoparticles are deduced using single particle impact electrochemical measurements in buffered aqueous solutions across the pH range 2–11. Both hydrazine, N2H4, and protonated hydrazine N2H5+ are shown to be electroactive following Butler-Volmer kinetics, of which the relative contribution is strongly pH-dependent. The negligible interconversion between N2H4 and N2H5+ due to the sufficiently short timescale of the impact voltammetry, allows the analysis of the two electron transfer rates from impact signals thus reflecting the composition of the bulk solution at the pH in question. In this way the rate determining step in the oxidation of each specie is deduced to be a one electron step in which no protons are released and so likely corresponds to the initial formation of a very short-lived radical cation either in solution or adsorbed on the platelet. Overall the work establishes a generic method for the elucidation of the rate determining electron transfer in a multistep process free from any complexity imposed by preceding or following chemical reactions which occur on the timescale of conventional voltammetry.

scholarly journals Kinetics of electron transfer from NADH to the Escherichia coli nitric oxide reductase flavorubredoxin

FEBS Journal ◽  
2006 ◽  
Vol 274 (3) ◽  
pp. 677-686 ◽  
Author(s):  
João B. Vicente ◽  
Francesca M. Scandurra ◽  
João V. Rodrigues ◽  
Maurizio Brunori ◽  
Paolo Sarti ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Escherichia Coli ◽  
Electron Transfer ◽  
Nitric Oxide Reductase ◽  
Kinetics Of

Mechanism of photoinduced electron transfer in photosystem II reaction centers

BIOPHYSICS ◽  
2007 ◽  
Vol 52 (1) ◽  
pp. 40-45 ◽  
Author(s):  
I. B. Klenina ◽  
W. O. Feikema ◽  
P. Gast ◽  
M. G. Zvereva ◽  
I. I. Proskuryakov
Keyword(s):  
Electron Transfer ◽  
Photosystem Ii ◽  
Photoinduced Electron Transfer ◽  
Reaction Centers
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