scholarly journals The microbial metabolism of C1 compounds. The cytochromes of Pseudomaonas AM1

1975 ◽  
Vol 146 (2) ◽  
pp. 289-298 ◽  
Author(s):  
C Anthony
Keyword(s):  
Molecular Weight ◽  
Electron Transport ◽  
Cytochrome C ◽  
Isoelectric Point ◽  
Microbial Metabolism ◽  
Cytochrome O

Pseudomonas AM1 contains cytochromes a, b and c and more than one CO-binding pigment (cytochrome a3, cytochrome c and possibly a cytochrome o). The soluble cytochrome c has been purified; its isoelectric point is low and its molecular weight is 20000. This cytochrome is reduced in whole bacteria by all oxidizable substrates at rates determined by the primary dehydrogenases. A mutant lacking cytochrome c oxidizes all substrates except methanol, ethanol and methylamine; these no longer support growth. The role of cytochrome c in electron transport in Pseudomonas AM1 is discussed.

Characterization of Two Soluble Basic Cytochromes Isolated from the Anoxygenic Phototrophic Sulfur Bacterium Chlorobium phaeobacteroides

1989 ◽  
Vol 44 (1-2) ◽  
pp. 71-76 ◽  
Author(s):  
Ulrich Fischer
Keyword(s):  
Molecular Weight ◽  
Cytochrome C ◽  
Redox Potential ◽  
Isoelectric Point ◽  
Gel Filtration ◽  
Exchange Chromatography ◽  
Chlorobium Phaeobacteroides ◽  
Flavocytochrome C ◽  
Reduced State

Abstract Chlorobium phaeobacteroides contains two soluble basic c-type cytochromes, a flavocytochrome c-552 and a small cytochrome c-555. Both electron transfer proteins were highly purified by ion exchange chromatography and gel filtration. The flavocytochrome c-552 exhibits maxima at 552 nm, 523 nm and 416 nm in the reduced state and at 409.5 nm with two shoulders at 440 nm and 480 nm in the oxidized form. The best purity index (A280/A416)obtained was 0.65. The molecular properties of this flavocytochrome are as follows: isoelectric point, pH 9.5 - 10; redox potential, +63 mV; molecular weight, 56,000. Cytochrome c-555 is a small basic hemoprotein with an isoelectric point of pH 9.5 - 10, a molecular weight of 9,500 and a midpoint redox potential of +105 mV. The best purity index {A280/A418) obtained was 0.176. The oxidized form of this cytochrome has a maximum at 411.5 nm, while the reduced state shows three maxima (α-band at 554.5 nm; β-band at 523 nm, and γ-band at 418 nm). The a-band is asymmetrical with a typical shoulder at 551 nm.

Double-edged sword in cells: chemical biology studies of the vital role of cytochrome c in the intrinsic pre-apoptotic mitochondria leakage pathway

RSC Advances ◽  
2015 ◽  
Vol 5 (36) ◽  
pp. 28258-28269 ◽  
Author(s):  
Zhi-Peng Wang ◽  
Xiao-Zhe Ding ◽  
Jun Wang ◽  
Yi-Ming Li
Keyword(s):  
Cell Death ◽  
Electron Transport ◽  
Cytochrome C ◽  
Electron Transport Chain ◽  
Chemical Biology ◽  
Vital Role ◽  
Mitochondrial Electron Transport Chain ◽  
Transport Chain ◽  
Cyt C

Besides functioning as an electron transporter in the mitochondrial electron transport chain, cytochrome c (cyt c) is also one of the determinants in the execution of cell death.

Cytochromes of the Purple Sulfur Bacterium Ectothiorhodospira shaposhnikovii

1984 ◽  
Vol 39 (9-10) ◽  
pp. 894-901 ◽  
Author(s):  
Werner H. Kusche ◽  
Hans G. Trüper
Keyword(s):  
Molecular Weight ◽  
Cytochrome C ◽  
Redox Potential ◽  
Cytochrome B ◽  
High Spin ◽  
Isoelectric Point ◽  
Sodium Dodecylsulfate ◽  
Reduced Form ◽  
Reduced Sulfur Compounds ◽  
Purple Sulfur Bacterium

Abstract Two c-type cytochromes (a high spin cytochrome c′ and a low spin cytochrome c-553(549) with asymmetrical α-band) and a low spin cytochrome b-558 from the purple sulfur bacterium Ectothiorhodospira shaposhnikovii were purified by ion exchange chromatography and gel filtration and characterized. Cytochrome c′ has a molecular weight of 33000 (determined by sodium dodecylsulfate electrophoresis), an isoelectric point at pH 4.5 and a redox potential of +37 mV. Absorption spectra show in the oxidized state maxima at 404 nm and in the range of 635 nm, in the reduced form maxima at 426.5 nm, 549 nm and a shoulder at 435 nm. The best purity index obtained was 0.48 (A280/A426.5). Reduced cytochrome c′ reacts with carbon monoxide. Cytochrome c-553(549) has a molecular weight of 10400, an isoelectric point at pH 5.1 and a redox potential of +248 mV. The oxidized form shows the Soret-band at 410 nm. The reduced protein reveals an asymmetrical a-band at 553 nm with a shoulder at 549 nm, the a-band at 522 nm with a shoulder at 528 nm and the γ-band at 416 nm. The best purity index obtained was 0.18 (A280/A416). Roth cytochromes could be isolated from the soluble fraction as well as from Triton X-100 treated membranes. Furthermore very low amounts of cytochromes c-553 and c-552.5 could be detected in detergent treated chromatophores. Cytochrome 6-558 - obtained from cells grown in the presence of reduced sulfur compounds in the medium - seems to be soluble or only weakly bound to the membrane. It has a molecular weight of 15800. an isoelectric point at pH 4.1 and a redox potential of -210 mV. The hemoprotein shows absorption maxima at 424.5 nm. 526.5 nm and 556.5 nm in the reduced form and at 416 nm in the oxidized state. The best purity index obtained was 0.26 (A280/A42,4.5). In addition, there were hints for the occurrence of a high spin cytochrome b′. The cytochrome pattern as well as the amount of cytochromes were dependent on growth conditions.

The role of plastidic cytochrome c in algal electron transport and photophosphorylation

1978 ◽  
Vol 501 (2) ◽  
pp. 275-285 ◽  
Author(s):  
Herbert Böhme ◽  
Karl Josef Kunert ◽  
Peter Böger
Keyword(s):  
Electron Transport ◽  
Cytochrome C

scholarly journals The electron-transport chains of the obligate methylotroph Methylophilus methylotrophus

1980 ◽  
Vol 192 (2) ◽  
pp. 429-439 ◽  
Author(s):  
Andrew R. Cross ◽  
Christopher Anthony
Keyword(s):  
Electron Transport ◽  
Cytochrome C ◽  
Redox Potentials ◽  
Obligate Methylotroph ◽  
Methylophilus Methylotrophus ◽  
Cytochrome O ◽  
Cytochromes C ◽  
Band Absorption ◽  
Membrane Bound ◽  
Α Band

The cytochrome complement of Methylophilus methylotrophus and its respiratory properties were determined during batch culture and in continuous culture under conditions of methanol-, nitrogen- and O2-limitation. About 35% of the cytochrome c produced by the bacteria was released into the growth medium, and of the remaining cytochrome c about half was membrane-bound and half was soluble. Two cytochromes c were always present on membranes (redox potentials 375mV and 310mV), and these probably correspond to the soluble cytochromes c described previously [Cross & Anthony (1980) Biochem. J.192, 421–427]. A third minor component of cytochrome c (midpoint potential 356mV) was only detected on membranes of methanol-limited bacteria. M. methylotrophus always contained two membrane-bound cytochromes b with α-band absorption maxima of about 556 and 563nm (measured at room temperature) and midpoint potentials of 110 and 60mV respectively. There appeared to be relatively more of the cytochrome b563 in methanol-limited bacteria. A third b-type cytochrome with an α-band absorption maximum at 558 (at 77K) reacted with CO and had a high midpoint redox potential (260mV); it is thus a potential oxidase and hence is called cytochrome o. The roles of these cytochromes in electron transport were confirmed by investigating the patterns of respiratory inhibition. It is proposed that two cytochromes are physiological oxidases: cytochrome a+a3, which is present only in methanol-limited conditions, and the cytochrome o, which is induced 10-fold in conditions of methanol excess. Schemes for electron transport from methanol and NAD(P)H to O2 in M. methylotrophus under various limitations are proposed. Spectra and potentiometric titrations of cytochromes in whole cells and membranes of M. methylotrophus grown under various nutrient limitations have been deposited as Supplementary Publication SUP 50111 (10 pages) at the British Library Lending Division, Boston Spa, Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1978) 169, 5.

scholarly journals The role of cytochrome c diffusion in mitochondrial electron transport.

1988 ◽  
Vol 263 (11) ◽  
pp. 5248-5253 ◽  
Author(s):  
S S Gupte ◽  
C R Hackenbrock
Keyword(s):  
Electron Transport ◽  
Cytochrome C

The role of ligands in electron transport in nanocrystal solids

Nanoscale ◽  
2020 ◽  
Vol 12 (45) ◽  
pp. 23028-23035
Author(s):  
Artem R. Khabibullin ◽  
Alexander L. Efros ◽  
Steven C. Erwin
Keyword(s):  
Electron Transport ◽  
Theoretical Modeling

Theoretical modeling of wavefunction overlap in nanocrystal solids elucidates the important role played by ligands in electron transport.

Activation of cytochrome c to a peroxidase compound I-type intermediate by H2O2: relevance to redox signalling in apoptosis

2004 ◽  
Vol 71 ◽  
pp. 97-106 ◽  
Author(s):  
Mark Burkitt ◽  
Clare Jones ◽  
Andrew Lawrence ◽  
Peter Wardman
Keyword(s):  
Cytochrome C ◽  
Hydroxyl Radical ◽  
Redox Regulation ◽  
Chemotherapeutic Agents ◽  
Tyrosyl Radical ◽  
Compound I ◽  
Definitive Evidence ◽  
Enhanced Production ◽  
Physico Chemical

The release of cytochrome c from mitochondria during apoptosis results in the enhanced production of superoxide radicals, which are converted to H2O2 by Mn-superoxide dismutase. We have been concerned with the role of cytochrome c/H2O2 in the induction of oxidative stress during apoptosis. Our initial studies showed that cytochrome c is a potent catalyst of 2′,7′-dichlorofluorescin oxidation, thereby explaining the increased rate of production of the fluorophore 2′,7′-dichlorofluorescein in apoptotic cells. Although it has been speculated that the oxidizing species may be a ferryl-haem intermediate, no definitive evidence for the formation of such a species has been reported. Alternatively, it is possible that the hydroxyl radical may be generated, as seen in the reaction of certain iron chelates with H2O2. By examining the effects of radical scavengers on 2′,7′-dichlorofluorescin oxidation by cytochrome c/H2O2, together with complementary EPR studies, we have demonstrated that the hydroxyl radical is not generated. Our findings point, instead, to the formation of a peroxidase compound I species, with one oxidizing equivalent present as an oxo-ferryl haem intermediate and the other as the tyrosyl radical identified by Barr and colleagues [Barr, Gunther, Deterding, Tomer and Mason (1996) J. Biol. Chem. 271, 15498-15503]. Studies with spin traps indicated that the oxo-ferryl haem is the active oxidant. These findings provide a physico-chemical basis for the redox changes that occur during apoptosis. Excessive changes (possibly catalysed by cytochrome c) may have implications for the redox regulation of cell death, including the sensitivity of tumour cells to chemotherapeutic agents.

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