scholarly journals Purification and properties of a cross-linked complex between cytochrome c and cytochrome c peroxidase

1982 ◽  
Vol 201 (1) ◽  
pp. 9-18 ◽  
Author(s):  
G W Pettigrew ◽  
S Seilman
Keyword(s):  
Cytochrome C ◽  
Cytochrome C Peroxidase ◽  
Sodium Phosphate Buffer ◽  
Oxidation Reduction ◽  
Purification And Properties ◽  
Lysine Residues ◽  
The Cross ◽  
Nadh Cytochrome ◽  
Stable Association ◽  
Covalently Linked

Cytochrome c (horse heart) was covalently linked to yeast cytochrome c peroxidase by using the cleavable bifunctional reagent dithiobis-succinimidyl propionate in 5 mM-sodium phosphate buffer, pH 7.0. A cross-linked complex of molecular weight 48 000 was purified in approx. 10% yield from the reaction mixture, which contained 1 mol of cytochrome c and 1 mol of cytochrome c peroxidase/mol. Of the total 40 lysine residues, four to six were blocked by the cross-linking agent. Dithiobis-succinimidylpropionate can also cross-link cytochrome c to ovalbumin, but cytochrome c peroxidase is the preferred partner for cytochrome c in a mixture of the three proteins. The cytochrome c cross-linked to the peroxidase can be rapidly reduced by free cytochrome c-557 from Crithidia oncopelti, and the equilibrium obtained can be used to calculate a mid-point oxidation-reduction potential for the cross-linked cytochrome of 243 mV. Mitochondrial NADH-cytochrome c reductase will reduce the bound cytochrome only very slowly, but the rate of reduction by ascorbate at high ionic strength approaches that for free cytochrome c. Bound cytochrome c reduced by ascorbate can be re-oxidized within 10s by the associated peroxidase in the presence of equimolar H2O2. In the standard peroxidase assay the cross-linked complex shows 40% of the activity of the free peroxidase. Thus the intrinsic ability of each partner in the complex to take part in electron transfer is retained, but the stable association of the two proteins affects access of reductants.

scholarly journals On the relationship between oxidation-reduction potential and biological activity in cytochrome c analogues. Results from four novel two-fragment complexes

1987 ◽  
Vol 245 (3) ◽  
pp. 773-779 ◽  
Author(s):  
C J A Wallace ◽  
A E I Proudfoot
Keyword(s):  
Electron Transfer ◽  
Cytochrome C ◽  
Biological Activities ◽  
Amino Acid Residues ◽  
Redox Potentials ◽  
Peptide Bonds ◽  
Oxidation Reduction ◽  
Oxidation Reduction Potential ◽  
Stable Association ◽  
The Relationship

We have confirmed the propensity of fragments of cytochrome c to form complexes that reproduce the structure and, in part, the functionality, of the native protein by preparing four novel complexes. We have used trypsin under three different sets of conditions in sequence to prepare a contiguous two-fragment complex (1-55).(56-104). One of the intermediates is a stable overlapping complex (1-65).(56-104). Conditions for limited acid hydrolysis of peptide bonds in cytochrome c have been developed that optimize the yield of fragments (1-50) and (51-104). These two fragments also form a stable association, as do (1-50) and (56-104). These complexes are potentially useful for the semisynthesis of analogues modified in the region of the cleavage sites, which include a number of highly conserved amino acid residues, and are being used for studies of protein folding, interactions with oxidase, cytochrome c immunogenicity and of artificially induced spontaneous resyntheses between complexing fragments. Like other known two-fragment complexes of cytochrome c, they exhibit normal visible spectra, including the presence of the 695 nm band, indicative of a functional haem crevice. Studies of their biological activities and redox potentials lead to a number of conclusions on structure-function relationships in cytochrome c. Most significantly there is a linear relationship between the logarithm of electron-transfer rates from cytochrome c reductase and redox potential in this series of analogues, indicating that such transfer is thermodynamically controlled. This discovery contributes to our understanding of the interaction of cytochrome and reductase. Since the relationship is obeyed by other types of analogues, except for those that involve modification of the active site of cytochrome c, we have a useful diagnostic for those residues that participate directly in electron transfer.

Melatonin protects against cadmium-induced oxidative damage in different tissues of rat: a mechanistic insight

2019 ◽  
Vol 2 (2) ◽  
pp. 1-21 ◽  
Author(s):  
Elina Mitra ◽  
Bharati Bhattacharjee ◽  
Palash Kumar Pal ◽  
Arnab Kumar Ghosh ◽  
Sanatan Mishra ◽  
...  
Keyword(s):  
Cytochrome C ◽  
Oxidative Damage ◽  
Protein Carbonyl ◽  
Environmental Pollutant ◽  
Glutathione S Transferase ◽  
Protein Carbonyl Content ◽  
Wide Range ◽  
Liver And Kidney ◽  
Nadh Cytochrome ◽  
Cd Exposure

Cadmium (Cd) is a notorious environmental pollutant known for its wide range of toxicities to organisms. Thus, the present study is designed to examine whether melatonin, a potent antioxidant, protects against Cd-induced oxidative damage in the heart, liver and kidney of rats. Cd treatment at a dose of 0.44 mg/kg for 15 days caused severe damage in all these organs. These included significantly increased activities of SGPT, SGOT, lactate dehydrogenase- 1 and 5 and ALP and levels of total lactate, creatinine, lipid peroxidation, protein carbonyl content and reduced glutathione while the activities of superoxide dismutases, catalase, glutathione peroxidase, glutathione reductase and glutathione-S-transferase along with mitochondrial pyruvate dehydrogenase, isocitrate dehydrogenase, α-keto glutarate dehydrogenase, succinate dehydrogenase, NADH-cytochrome-c-oxidoreductase and cytochrome-c-oxidase were significantly reduced by Cd. However, if melatonin was given orally 30 min before Cd injection, all these alterations induced by Cd were significantly preserved by melatonin. Histological observations also demonstrated that Cd exposure caused cellular lesions, promoting necrotic or apoptotic changes. Notably, all these changes were significantly protected by melatonin. The results suggest that melatonin is a beneficial molecule to ameliorate Cd-induced oxidative damage in the heart, liver and kidney tissues of rats with its powerful antioxidant capacity, heavy metal chelating activity and competition of binding sites with Cd to the GSH and catalase.

scholarly journals Conversion of the proximal histidine ligand to glutamine restores activity to an inactive mutant of cytochrome c peroxidase.

1992 ◽  
Vol 267 (36) ◽  
pp. 25656-25659
Author(s):  
K Choudhury ◽  
M Sundaramoorthy ◽  
J.M. Mauro ◽  
T.L. Poulos
Keyword(s):  
Cytochrome C ◽  
Cytochrome C Peroxidase

scholarly journals Studies on Cytochrome c Peroxidase

1966 ◽  
Vol 241 (22) ◽  
pp. 5347-5352 ◽  
Author(s):  
Takashi Yonetani ◽  
David F. Wilson ◽  
Bette Seamonds
Keyword(s):  
Cytochrome C ◽  
Cytochrome C Peroxidase
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