Spectroscopic studies of Rhodobacter capsulatus cytochrome c′ in the isolated state and in intact cells

1992 ◽  
Vol 1100 (2) ◽  
pp. 184-188 ◽  
Author(s):  
Fayez Monkara ◽  
Stephen J. Bingham ◽  
Fahmi H.A. Kadir ◽  
Alastair G. McEwan ◽  
Andrew J. Thomson ◽  
...  
Keyword(s):  
Cytochrome C ◽  
Rhodobacter Capsulatus ◽  
Spectroscopic Studies ◽  
Intact Cells

scholarly journals Metformin inhibits mitochondrial permeability transition and cell death: a pharmacological in vitro study

2004 ◽  
Vol 382 (3) ◽  
pp. 877-884 ◽  
Author(s):  
Bruno GUIGAS ◽  
Dominique DETAILLE ◽  
Christiane CHAUVIN ◽  
Cécile BATANDIER ◽  
Frédéric De OLIVEIRA ◽  
...  
Keyword(s):  
Cell Death ◽  
Cytochrome C ◽  
Mitochondrial Permeability Transition ◽  
Permeability Transition ◽  
Cytochrome C Release ◽  
Intact Cells ◽  
Human Carcinoma ◽  
Butyl Hydroperoxide ◽  
Mitochondrial Permeability ◽  
New Findings

Metformin, a drug widely used in the treatment of Type II diabetes, has recently received attention owing to new findings regarding its mitochondrial and cellular effects. In the present study, the effects of metformin on respiration, complex 1 activity, mitochondrial permeability transition, cytochrome c release and cell death were investigated in cultured cells from a human carcinoma-derived cell line (KB cells). Metformin significantly decreased respiration both in intact cells and after permeabilization. This was due to a mild and specific inhibition of the respiratory chain complex 1. In addition, metformin prevented to a significant extent mitochondrial permeability transition both in permeabilized cells, as induced by calcium, and in intact cells, as induced by the glutathione-oxidizing agent t-butyl hydroperoxide. This effect was equivalent to that of cyclosporin A, the reference inhibitor. Finally, metformin impaired the t-butyl hydroperoxide-induced cell death, as judged by Trypan Blue exclusion, propidium iodide staining and cytochrome c release. We propose that metformin prevents the permeability transition-related commitment to cell death in relation to its mild inhibitory effect on complex 1, which is responsible for a decreased probability of mitochondrial permeability transition.

scholarly journals Absence of Thiol-Disulfide Oxidoreductase DsbA Impairs cbb3-Type Cytochrome c Oxidase Biogenesis in Rhodobacter capsulatus

2017 ◽  
Vol 8 ◽  
Author(s):  
Ozlem Onder ◽  
Andreia F. Verissimo ◽  
Bahia Khalfaoui-Hassani ◽  
Annette Peters ◽  
Hans-Georg Koch ◽  
...  
Keyword(s):  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Rhodobacter Capsulatus ◽  
Disulfide Oxidoreductase

RESPIRATORY CARRIERS AND THE NATURE OF THE REDUCED DIPHOSPHOPYRIDINE NUCLEOTIDE OXIDASE SYSTEM IN XANTHOMONAS PHASEOLI

1960 ◽  
Vol 38 (1) ◽  
pp. 79-93 ◽  
Author(s):  
R. M. Hochster ◽  
C. G. Nozzolillo
Keyword(s):  
Cytochrome C ◽  
Reductase Activity ◽  
Inorganic Ions ◽  
Product Formation ◽  
Intact Cells ◽  
Oxidase System ◽  
Clear Cut ◽  
Highly Active ◽  
Inhibitor Study ◽  
Terminal Oxidation

Intact cells and cell-free extracts of the phytopathogenic organism Xanthomonas phaseoli have been shown to contain flavoprotein and the respiratory carriers: cytochrome b1, cytochrome a1, and cytochrome a2. The reduced forms of these respiratory pigments are produced upon addition to a clear extract of substrate amounts of DPNH.The highly active DPNH oxidase system in extracts of this organism has been studied as to requirements for inorganic ions, optimum pH, product formation, distribution, and solubilization. Carbon monoxide inhibits the terminal oxidation system; this effect is reversed by bright light.An inhibitor study has shown members of the phenothiazine family of compounds to be most effective, followed by amytal, cyanide, BAL, atabrine, and pCMB. The most notable of the substances which did not inhibit were antimycin A, one of the quinoline-N-oxides, and azide.The possibility exists that H2O2may also be formed during the oxidation of DPNH although clear-cut evidence for its presence was difficult to obtain. X. phaseoli extracts do not contain a DPNH peroxidase. They exhibit, however, some DPNH – cytochrome c reductase activity which is believed to be quite independent of the DPNH oxidase system. The extracts are devoid of cytochrome c oxidase activity although they contain a respiratory system which readily oxidizes p-phenylenediamine.

NMR Spectroscopic Studies of β-Methyl-Pyridine Binding to Cytochrome C

1998 ◽  
Vol 31 (5) ◽  
pp. 1075-1087 ◽  
Author(s):  
Jun Lu ◽  
Dejian Ma ◽  
Jun Hu ◽  
Wenxia Tang ◽  
Dexu Zhu
Keyword(s):  
Cytochrome C ◽  
Spectroscopic Studies ◽  
Methyl Pyridine

scholarly journals Oxygen affinity of the respiratory chain of Acanthamoeba castellanii

1983 ◽  
Vol 214 (1) ◽  
pp. 47-51 ◽  
Author(s):  
D Lloyd ◽  
H Mellor ◽  
J L Williams
Keyword(s):  
Plasma Membrane ◽  
Cytochrome C ◽  
Cytochrome B ◽  
Respiratory Chain ◽  
Oxygen Affinity ◽  
Acanthamoeba Castellanii ◽  
Intact Cells ◽  
Cytochrome Aa3 ◽  
Isolated Mitochondria ◽  
Soil Amoeba

Apparent Km values for O2 for the soil amoeba Acanthamoeba castellanii determined polarographically and by bioluminescence gave similar values (0.37 and 0.41 microM respectively). Mitochondria oxidizing succinate or NADH in the presence or absence of ADP gave values in the range 0.21-0.36 microM-O2. Oxidation of respiratory-chain components to 50% of the aerobic steady states in intact cells was observed at the following O2 concentrations: cytochrome aa3, 0.1-0.25 microM; cytochrome c, 0.3-0.6 microM; cytochrome b, 0.35-0.45 microM; flavoprotein, 2 microM. In isolated mitochondria corresponding values for a-, c- and b-type cytochromes were 0.007, 0.035-0.05 and 0.06-0.09 microM-O2. It is concluded that an O2 gradient exists between plasma membrane and mitochondria in A. castellanii.

The catalytic mechanism for NO production by the mitochondrial enzyme, sulfite oxidase

2019 ◽  
Vol 476 (13) ◽  
pp. 1955-1956
Author(s):  
Bulent Mutus
Keyword(s):  
Steady State ◽  
Cytochrome C ◽  
Protein Engineering ◽  
Catalytic Mechanism ◽  
Spectroscopic Studies ◽  
Sulfite Oxidase ◽  
Nitrite Reduction ◽  
No Production ◽  
Intramolecular Electron Transfer ◽  
Vis Spectroscopy

Abstract Recently, Guenter Schwarz and colleagues published an elegant study in the Biochemical Journal (2019) 476, 1805–1815 which combines kinetic and spectroscopic studies with protein engineering to provide a mechanism for sulfite oxidase (SO)-catalyzed nitrite reduction that yields nitric oxide (NO). This work is noteworthy as it demonstrates that (i) for NO generation, both sulfite and nitrite must bind to the same molybdenum (Mo) center; (ii) upon sulfite reduction, Mo is reduced from +6 (MoVI) to +4 (MoIV) and MoIV reduces nitrite to NO yielding MoV; (iii) the heme moiety, linked to the Mo-center by an 11 amino acid residue tether, gets reduced by intramolecular electron transfer (IET) resulting in MoV being oxidized to MoVI; (iv) the reduced heme transfers its electron to a second nitrite molecule converting it to NO; (v) the authors demonstrate steady-state NO production in the presence of the natural electron acceptor cytochrome c; (vi) Finally, the authors use protein engineering to shorten the heme tether to reduce the heme-Mo-center distance with the aim of increasing NO production. Consequently, the rate of IET to cytochrome c is decreased but the enzymatic turnover rate for NO production is increased by ∼10-fold. This paper is unique as it provides strong evidence for a novel mechanism for steady-state NO production for human mitochondrial SO and serves as a potential template for studying NO production mechanisms in other enzymes by integrating the information gained from enzyme kinetics with EPR and UV/vis spectroscopy and protein engineering.

Redox and Spin-State Control of the Activity of a Diheme Cytochrome C Peroxidase — Spectroscopic studies

1995 ◽  
pp. 141-163 ◽  
Author(s):  
Susana Prazeres ◽  
Isabel Moura ◽  
Raymond Gilmour ◽  
Graham Pettigrew ◽  
Natarajan Ravi ◽  
...  
Keyword(s):  
Cytochrome C ◽  
Spin State ◽  
Cytochrome C Peroxidase ◽  
Spectroscopic Studies ◽  
State Control
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