Ionic strength dependence of the non-physiological electron transfer between flavodoxin and cytochrome c 553 from D. vulgaris

2000 ◽  
Vol 5 (6) ◽  
pp. 730-737 ◽  
Author(s):  
Sheila J. Sadeghi ◽  
Francesca Valetti ◽  
Carlos A. Cunha ◽  
Maria J. Romão ◽  
Cláudio M. Soares ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Ionic Strength ◽  
Cytochrome C ◽  
Ionic Strength Dependence ◽  
Strength Dependence

Ionic Strength Dependence of the Reaction between Methanol Dehydrogenase and Cytochrome c-551i: Evidence of Conformationally Coupled Electron Transfer

Biochemistry ◽  
1994 ◽  
Vol 33 (42) ◽  
pp. 12600-12608 ◽  
Author(s):  
Thomas K. Harris ◽  
Victor L. Davidson ◽  
Longyin Chen ◽  
F. Scott Mathews ◽  
Zong-Xiang Xia
Keyword(s):  
Electron Transfer ◽  
Ionic Strength ◽  
Cytochrome C ◽  
Methanol Dehydrogenase ◽  
Ionic Strength Dependence ◽  
Strength Dependence

scholarly journals Cytochrome b2, an electron carrier between flavocytochrome b2 and cytochrome c. Rapid kinetic characterization of the electron-transfer parameters with ionic-strength-dependence

1987 ◽  
Vol 245 (1) ◽  
pp. 159-165 ◽  
Author(s):  
C Capeillère-Blandin ◽  
J Albani
Keyword(s):  
Electron Transfer ◽  
Exchange Rate ◽  
Ionic Strength ◽  
Cytochrome C ◽  
Rate Constant ◽  
Order Rate Constant ◽  
Electron Exchange ◽  
Ionic Strength Dependence ◽  
Flavocytochrome B2 ◽  
Reaction Complex

The oxidation-reduction properties of free cytochrome b2 isolated by controlled proteolysis from flavocytochrome b2, i.e. the flavodehydrogenase-bound cytochrome b2, were investigated by using stopped-flow spectrophotometry. The rapid kinetics of the reduction of cytochrome b2 by flavocytochrome b2 in the presence of L-lactate are reported. The self-exchange rate constant between reduced cytochrome b2 bound to the flavodehydrogenase and free cytochrome b2 was determined to be 10(5) M−1 X S−1 at 5 degrees C, I 0.2 and pH 7.0. The specific electron-transfer reaction between reduced cytochrome b2 and cytochrome c was also studied, giving an apparent second-order rate constant of 10(7) M−1 X S−1 at 5 degrees C, I 0.2 and pH 7.0. This electron-exchange rate is slightly modulated by ionic strength, following the Debye-Hückel relationship with a charge factor Z1Z2 = −1.9. Comparison of these data with those for the reduction of cytochrome c by flavodehydrogenase-bound cytochrome b2 [Capeillère-Blandin (1982) Eur. J. Biochem. 128, 533-542] leads to the conclusion that the intramolecular electron exchange between haem b2 and haem c within the reaction complex occurs at a rate very similar to that determined experimentally in presence of the flavodehydrogenase domain. The low reaction rate observed with free cytochrome b2 is ascribed to the low stability of the reaction complex formed between free cytochrome b2 and cytochrome c.

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