scholarly journals The oxidation-state-dependent ATP-binding site of cytochrome c. A possible physiological significance

1986 ◽  
Vol 236 (2) ◽  
pp. 359-364 ◽  
Author(s):  
B E Corthésy ◽  
C J A Wallace
Keyword(s):  
Cytochrome C ◽  
Binding Site ◽  
Oxidation State ◽  
Biological Properties ◽  
Physiological Significance ◽  
Horse Heart Cytochrome ◽  
Atp Binding Site ◽  
Recognition Sites ◽  
State Dependent ◽  
Horse Heart Cytochrome C

Cytochrome c binds certain physiological anions that are known to modulate the biological properties of the protein, although it is not known whether this effect is fortuitous or has physiological significance. We have examined the ability of the protein and its semisynthetic analogues to associate with certain of these anions, e.g. ATP, ADP, Pi and citrate. Our results show that specific residues or clusters of residues on the surface of horse heart cytochrome c are involved in the recognition sites for these anions. We also observed that binding at one site is linked to the oxidation state of the protein.

scholarly journals The oxidation-state-dependent ATP-binding site of cytochrome c. Implication of an essential arginine residue and the effect of occupancy on the oxidation-reduction potential

1988 ◽  
Vol 252 (2) ◽  
pp. 349-355 ◽  
Author(s):  
B E Corthésy ◽  
C J Wallace
Keyword(s):  
Cytochrome C ◽  
Oxidation State ◽  
Dependent Manner ◽  
Redox Potentials ◽  
Redox Systems ◽  
Atp Binding Site ◽  
Oxidation Reduction ◽  
State Dependent ◽  
Oxidation Reduction Potential

Arg-91 is not part of the active site of cytochrome c that mediates binding and electron transfer, yet it is absolutely conserved in eukaryotic cytochromes c, indicating a special function. The physicochemical properties of analogues are unaffected by the modification of this residue, so they can be used with confidence to study the role of Arg-91. We have established limiting conditions under which this residue alone is specifically modified by cyclohexane-1,2-dione, and have subsequently shown that ATP, and to a lesser extent ADP or Pi, protects it from the action of the reagent in an oxidation-state-dependent manner. These observations strongly support the idea that this site exerts a controlling influence on cytochrome c activity in the electron transport or other cellular redox systems, and we have commenced a study of how that influence might operate. We find that the redox potentials of both cytochrome c and analogue are little affected by changing ATP or Pi concentrations.

Kinetics and mechanism of the reaction between oxidized cytochrome c and ascorbic acid

1991 ◽  
Vol 56 (2) ◽  
pp. 478-490 ◽  
Author(s):  
Joaquin F. Perez-Benito ◽  
Conchita Arias
Keyword(s):  
Ascorbic Acid ◽  
Cytochrome C ◽  
Redox Reactions ◽  
Arrhenius Equation ◽  
Horse Heart Cytochrome ◽  
First Order ◽  
Acidic Form ◽  
Ph Range ◽  
Horse Heart Cytochrome C ◽  
Mechanism Of The Reaction

The reaction between horse-heart cytochrome c and ascorbic acid has been investigated in the pH range 5.5 – 7.1 and at 10.0 – 25.0 °C. The rate shows a first-order dependence on the concentration of cytochrome c, it increases in a non-linear way as the concentration of ascorbic acid increases, it increases markedly with increasing pH and, provided that the ionic strength of the medium is high enough, it fulfills the Arrhenius equation. The apparent activation energy increases as the pH of the solution increases. The results have been explained by means of a mechanism that includes the existence of an equilibrium between two forms (acidic and basic) of oxidized cytochrome c: cyt-H+ -Fe3+ + OH- cyt -Fe3+ + H2O, whose equilibrium constant is (6.7 ± 1.4). 108 at 25.0 °C, the acidic form being more reducible than the basic one. It is suggested that there is a linkage of hydrogenascorbate ion to both forms of cytochrome c previous to the redox reactions. Two possibilities for the oxidant-reductant linkage (binding and adsorption) are discussed in detail.

ChemInform Abstract: Total Synthesis of Horse Heart Cytochrome c

ChemInform ◽  
2010 ◽  
Vol 23 (27) ◽  
pp. no-no
Author(s):  
C. DI BELLO ◽  
C. VITA ◽  
L. GOZZINI
Keyword(s):  
Cytochrome C ◽  
Total Synthesis ◽  
Horse Heart Cytochrome ◽  
Horse Heart Cytochrome C
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