Kinetics of reduction of eight viologens by dithionite ion

1985 ◽  
Vol 107 (9) ◽  
pp. 2632-2635 ◽  
Author(s):  
K. Tsukahara ◽  
R. G. Wilkins
Keyword(s):  
Dithionite Ion ◽  
Kinetics Of ◽  
Kinetics Of Reduction

scholarly journals The vanadium- and molybdenum-containing nitrogenases of Azotobacter chroococcum. Comparison of mid-point potentials and kinetics of reduction by sodium dithionite of the iron proteins with bound magnesium adenosine 5′-diphosphate

1988 ◽  
Vol 251 (1) ◽  
pp. 165-169 ◽  
Author(s):  
J Bergström ◽  
R R Eady ◽  
R N F Thorneley
Keyword(s):  
Sodium Dithionite ◽  
Azotobacter Chroococcum ◽  
Effective Electron ◽  
Iron Proteins ◽  
Fe Protein ◽  
Protein Components ◽  
Dithionite Ion ◽  
Kinetics Of ◽  
Kinetics Of Reduction

The mid-point potentials of the Fe protein components (Ac2 and Ac2* respectively) of the Mo nitrogenase and V nitrogenase from Azotobacter chroococcum were determined in the presence of MgADP to be −450 mV (NHE) [Ac2(MgADP)2-Ac2*ox.(MgADP)2 couple] and −463 mV (NHE) [Ac2* (MgADP)2-Ac2*ox.(ADP)2 couple] at 23 degrees C at pH 7.2. These values are consistent with a flavodoxin characterized by Deistung & Thorneley [(1986) Biochem. J. 239, 69-75] with Em = −522 mV (NHE) being an effective electron donor to both the Mo nitrogenase and the V nitrogenase in vivo. Ac2*ox.(MgADP)2 and Ac2*ox.(MgADP)2 were reduced by SO2.- (formed by the predissociation of dithionite ion, S2O4(2-)) at similar rates, k = 4.7 × 10(6) +/- 0.5 × 10(6) M-1.s-1 and 3.2 × 10(6) +/- 0.2 × 10(6) M-1.s-1 respectively, indicating structural homology at the electron-transfer site associated with the [4Fe-4S] centre in these proteins.

The effect of origin and physico-chemical properties on the kinetics of reduction of mixed NiO-Fe2O3 oxides with hydrogen

1986 ◽  
Vol 51 (10) ◽  
pp. 2098-2108 ◽  
Author(s):  
Milan Pospíšil ◽  
Jan Topinka
Keyword(s):  
Mixed Oxides ◽  
Mutual Influence ◽  
Spinel Phase ◽  
Chemical Properties ◽  
Inhibitory Effect ◽  
Chemical Parameters ◽  
Physico Chemical ◽  
Preliminary Annealing ◽  
Kinetics Of ◽  
Kinetics Of Reduction

We investigated the effect of origin and some physico-chemical parameters on the kinetics of reduction with hydrogen of two series of mixed NiO-Fe2O3 oxides differing by their composition, the character of their precursors (mixed crystalline nitrates and coprecipitated hydroxides) and their decomposition temperature.This effect manifested itself by different magnitudes of specific surfaces of the mixed oxides and coherent regions of present phases as well as by different oxidizing abilities of the surface and differences in morphology and phase composition of corresponding samples in both series investigated. Nonlinear or nonmonotonous composition dependences of physico-chemical parameters investigated point to a mutual influence of individual components, which is also a function of the system origin and which modifies its reactivity during its reduction with hydrogen. The kinetics of the reduction was studied thermogravimetrically at 320-410 °C. The reduction of oxides of the hydroxide origin is catalytically accelerated by primarily reduced nickel, whereas in corresponding samples of the nitrate series, the total NiO is bound to the spinel phase and the reduction is delayed. Experimental IR spectra, the effect of preliminary annealing and DTA of the mixed oxides point to an inhibitory effect of water, which is constitutionally bound in trace admixtures of the goethite phase, on the kinetics of reduction of samples in the hydroxide series.

Kinetics of reduction of the cytochrome C3 from Desulfovibriovulgaris

1978 ◽  
Vol 84 (2) ◽  
pp. 435-440 ◽  
Author(s):  
V. Favaudon ◽  
C. Ferradini ◽  
J. Pucheault ◽  
L. Gilles ◽  
J. Le Gall
Keyword(s):  
Cytochrome C3 ◽  
Kinetics Of ◽  
Kinetics Of Reduction
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