Characterization of a new membrane-bound cytochrome c of Rhodopseudomonas capsulata

FEBS Letters ◽  
1983 ◽  
Vol 152 (2) ◽  
pp. 251-255 ◽  
Author(s):  
Hendrik Hüdig ◽  
Gerhart Drews
Keyword(s):  
Cytochrome C ◽  
Rhodopseudomonas Capsulata ◽  
Membrane Bound

Purification and Partial Characterization of the Soluble NADH Dehydrogenase from the Phototrophic Bacterium Rhodopseudomonas capsulata

1984 ◽  
Vol 39 (1-2) ◽  
pp. 68-72 ◽  
Author(s):  
Toshihisa Ohshima ◽  
Matsumi Ohshima ◽  
Gerhart Drews
Keyword(s):  
Cytochrome C ◽  
Nadh Dehydrogenase ◽  
Rhodopseudomonas Capsulata ◽  
Subunit Structure ◽  
Ph Optimum ◽  
Single Polypeptide Chain ◽  
Membrane Bound ◽  
Single Polypeptide ◽  
Sepharose 4B

Abstract Soluble NADH dehydrogenase was purified to homogeneity from chemotrophically grown cells of Rhodopseudomonas capsulata by ammonium sulfate fractionation, AH -Sepharose 4B chromatography and FMN-Sepharose 6B affinity chromatography. The enzyme contains a single polypeptide chain of an apparent M, of 37000, suggesting that the subunit structure is different from that of the membrane-bound enzyme. The purified soluble NADH dehydrogenase requires flavin compounds, e.g., FMN, FAD and riboflavin, for activity. Addition of FMN and FAD. but not riboflavin, to the enzyme solution stabilized the enzyme. The pH optimum for activity was at 7.5. The enzyme was specific for NADH as an electron donor while NADPH was inert. Menadione, ferricyanide, cytochrome c and DCIP served as an electron acceptor. The M ichaelis constants for NADH. DCIP, FM N. and cytochrome c were 45, 2.9. 7.9 and 15 μM, respectively. Many properties of soluble NADH dehydrogenase were substantially different from those of the membrane-bound enzyme, suggesting different functions.

Isolation and Partial Characterization of the Membrane-Bound NADH Dehydrogenase from the Phototrophic Bacterium Rhodopseudomonas capsulata

1981 ◽  
Vol 36 (5-6) ◽  
pp. 400-406 ◽  
Author(s):  
Toshihisa Ohshima ◽  
Gerhart Drews
Keyword(s):  
Nadh Dehydrogenase ◽  
Deae Cellulose ◽  
Sodium Deoxycholate ◽  
Pyridine Nucleotide ◽  
Sodium Cholate ◽  
Rhodopseudomonas Capsulata ◽  
Michaelis Constant ◽  
Membrane Bound ◽  
Ph Dependent

Abstract Chemotrophically grown cells of Rhodopseudomonas capsulata contain at least three different pyridine nucleotide dehydrogenases, i) a soluble, found in the supernatant (144000 × g) of cell free extracts, NADH-dependent, ii) a mem brane-bound, NADH-dependent, and iii) a soluble, found in the supernatant N AD PH dependent. The membrane-bound NADH dehydrogenase (E.C. 1.6.99.3) has been solubilized by sodium deoxycholate treatm ent of m em branes and purified 75 fold by column chrom atography on Sephadex G-150 and DEAE cellulose in the presence of sodium cholate. The native enzyme has an apparent molecular mass (Mr) of 97 000, containing polypeptides of Mr of about 15 000. The pH optim um was at 7.5. The enzyme was specific for NADH. The Michaelis constant for NADH and DCIP were 4.0 and 63 μm, respectively. The enzyme was inactivated by FMN, riboflavin and NADH. In contrast, the soluble NADH-dehydrogenase (i) was activated by FMN.

Characterization of a Structural Model of Membrane Bound Cytochrome c-550 from Bacillus subtilis

2000 ◽  
Vol 377 (1) ◽  
pp. 22-30 ◽  
Author(s):  
Pamela S. David ◽  
Previn S. Dutt ◽  
Brent Wathen ◽  
Zongchoa Jia ◽  
Bruce C. Hill
Keyword(s):  
Bacillus Subtilis ◽  
Cytochrome C ◽  
Structural Model ◽  
Membrane Bound

scholarly journals Characterization of oxidation of glutathione by cytochrome c

2021 ◽  
Author(s):  
K. B. Csomó ◽  
B. Alasztics B ◽  
A. P. Sándor ◽  
A. A. Belik ◽  
G. Varga ◽  
...  
Keyword(s):  
Cytochrome C ◽  
Respiratory Chain ◽  
Oxygen Electrode ◽  
Oxidize Glutathione ◽  
Mitochondrial Oxygen Consumption ◽  
Anionic Phospholipids ◽  
Cyt C ◽  
Membrane Bound ◽  
Anionic Lipids

AbstractCytochrome c is a member of the respiratory chain of the mitochondria. Non-membrane-bound (free) cytochrome c can be reduced by gluthatione as well as ascorbic acid. We investigated the effect of pH, Ca2+, Mg2+ and anionic phospholipids on the reduction of cytochrome c by glutathione.The reduction of cytochrome c by thiols was measured using photometry. Mitochondrial oxygen consumption was detected by use of oxygen electrode. Glutathione does not reduce cytochrome c at pH = 7.0 in the absence of Ca2+ and Mg2+. The reduction of cytochrome c by glutathione is inhibited by anionic lipids, especially cardiolipin. The typical conditions of apoptosis—elevated pH, Ca2+ level and Mg2+—increases the reduction of cytochrome c. Glutathione (5 mM) causes increased mitochondrial O2 consumption at pH = 8.0, in the presence of ADP either 1 mM Mg2+ or 1 mM Ca2+. Our results suggest that membrane bound cyt c does not oxidize glutathione. Free (not membrane bound) cytochrome c can oxidize glutathione. In mitochondria, O2 is depleted only in the presence of ADP, so the O2 depletion observed in the presence of glutathione can be related to the respiratory chain. Decreased glutathione levels play a role in apoptosis. Therefore, membrane unbound cyt c can contribute to apoptosis by oxidation of glutathione.

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