Conformation of cytochromes. VII. Circular dichroism studies N-bromosuccinimide-modified horse heart cytochrome c preparations

Biochemistry ◽  
1972 ◽  
Vol 11 (23) ◽  
pp. 4203-4208 ◽  
Author(s):  
Yash P. Myer
Keyword(s):  
Circular Dichroism ◽  
Cytochrome C ◽  
Horse Heart Cytochrome ◽  
Horse Heart Cytochrome C ◽  
Circular Dichroïsm

scholarly journals Iso-cytochrome c species from baker's yeast. Analysis of their circular-dichroism spectra

1976 ◽  
Vol 157 (3) ◽  
pp. 773-775 ◽  
Author(s):  
Y Looze ◽  
E Polastro ◽  
C Gielens ◽  
J Léonis
Keyword(s):  
Circular Dichroism ◽  
Cytochrome C ◽  
Visible Region ◽  
Helical Structure ◽  
Baker’S Yeast ◽  
Baker's Yeast ◽  
Circular Dichroism Spectra ◽  
Horse Heart Cytochrome ◽  
Horse Heart Cytochrome C ◽  
Circular Dichroïsm

The circular-dichroism spectra of baker's-yeast iso-1- (methylated and unmethylated forms) and iso-2-cytochrome c species were examined between 200 and 600nm. In the visible region the yeast haemoproteins have characteristics nearly indistinguishable from those of horse heart cytochrome c. From the spectra in the u.v. region the latter appears, however, to be more helical. It is proposed that the likely element of non-helical structure in iso-1-cytochrome c is residues 62-70.

Influence of glycerol on the structure and redox properties of horse heart cytochrome c. A circular dichroism and electrochemical study

1996 ◽  
Vol 15 (7) ◽  
pp. 599-606 ◽  
Author(s):  
Giampiero De Sanctis ◽  
Alessandra Maranesi ◽  
Tommaso Ferri ◽  
Alessandro Poscia ◽  
Franca Ascoli ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Cytochrome C ◽  
Redox Properties ◽  
Electrochemical Study ◽  
Horse Heart Cytochrome ◽  
Horse Heart Cytochrome C ◽  
Circular Dichroïsm

scholarly journals Magnetization curves of haemoproteins measured by low-temperature magnetic-circular-dichroism spectroscopy

1980 ◽  
Vol 191 (2) ◽  
pp. 411-420 ◽  
Author(s):  
A J Thomson ◽  
M K Johnson
Keyword(s):  
Circular Dichroism ◽  
Cytochrome C ◽  
High Spin ◽  
Ground State ◽  
Magnetic Circular Dichroism ◽  
Striking Difference ◽  
Zero Field ◽  
Magnetization Curves ◽  
Horse Heart Cytochrome ◽  
Circular Dichroïsm

The magnetic-circular-dichroism (m.c.d.) spectra of methymyoglobin cyanide and oxidized horse heart cytochrome c were measured in the region of the Soret band over a range of temperatures from 1.5 to 50 K and in fields from 0 to 5T. A similar study has been made with reduced bovine heart cytochrome c oxidase, which contains one high-spin ferrous haem, namely a3. M.c.d. magnetization curves characteristic of an isolated Kramer's ground state with spin S = 1/2. These curves contrast with the magnetization curve of the high-spin ferrous haem with spin S = 2. The electronic ground state of the latter compound contains zero-field components that are thermally accessible over the temperature range of the experiment. Hence the magnetization curves are a complex nested set. The magnetization curves of the S = 1/2 proteins were analysed and it is shown that it is possible to make estimates of the ground-state g-factors even in the presence of rhombic anisotropy, provided that some knowledge of the polarizations of the electronic transitions is available. The striking difference between the m.c.d. magnetization curves of a simple S = 1/2 paramagnet and magnetically complex ground state should prove extremely useful when m.c.d. spectroscopy is sued to probe the magentic properties of metal centres in proteins, and should have wide application beyond the field of haemoproteins.

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.

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