Potentiometric and Magnetometric Study of the Duroquinone System

Michaelis, Leonor; Schubert, Maxwell; Reber, R. K.; Kuck, J. A.; Granick, Steve

doi:10.1021/ja01274a042

Cited by 54 publications

(8 citation statements)

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“…Furthermore, at higher sulfide concentrations (>200yM) the reduction of quinone in the absence of membranes increased subsrantially within the measuring time of a few minutes. Probably, chemical reduction of quinones is autocatalytically stimulated by the accumulation of small amounts of semiquinone during the course of the reaction [14]. Therefore, we avoided using sulfide and quinone concentrations higher than 40 PM, and we corrected SQR rates for the rates obtained with boiled membranes.…”

Section: Resultsmentioning

confidence: 99%

Sulfide quinone reductase (SQR) activity in Chlorobium

et al. 1992

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Membranes of the green sulfur bacterium. Clrlorobiu,~ lhticoh f. rltiostr~uto~lriit~r,t. catalyze the reduction of externally added isoprcnoid quinones by sultide. This activity is highly sensitive to stigmatellin and aurachins. It is also inhibited by 2-n-nonyl4hydroxyquinolinc&oxidc, anlimycin. myxothiazol and cyanide. II is concluded that in sulfide oxidizing bacteria like Ct'tlorobittttr, sulfide oxidation involves a sulfidequinone reductasc (SQR) similar to the one round in Oscilurori~t littmcticu [Atieli. B..

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Section: Resultsmentioning

confidence: 99%

Sulfide quinone reductase (SQR) activity in Chlorobium

et al. 1992

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“…Oxygen oxidation Most of the organic developing agents belong to types which can form semiquinones as oxidation intermediates (71, 72). Durohydroquinone, for example, is oxidized to duroquinone by way of the radical durosemiquinone (73). The percentage of the radical in equilibrium with the fully oxidized and fully reduced forms increases markedly with the alkalinity of the solution.…”

Section: The Developing Agentsmentioning

confidence: 99%

Reduction of Silver Halides and the Mechanism of Photographic Development.

James¹,

Kornfeld²

1942

Chem. Rev.

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“…However, the possibility of formation of the semiquinone anion radical, as described by V, depends critically on stabilization mechanisms for QH • . For example, in alkaline aqueous solution of stable semiquinones, Q •- is almost exclusively formed . Unfortu-nately, the structure of quinhydrones in media of low dielectric permittivity has not been studied.…”

Section: Discussionmentioning

confidence: 99%

Potential Dependence of Transmembrane Electron Transfer across Phospholipid Bilayers Mediated by Ubiquinone 10

et al. 1996

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Transmembrane electron transfer across phospholipid bilayer membranes (BLMs) mediated by ubiquinone have been investigated. The membranes were prepared by the brush method and patch-clamp micropipet techniques and were used to separate identical aqueous Fe(II)/Fe(III) citrate solution. Electron transfer across the BLMs was observed on applying a potential difference across the system. The current, and thus the transmembrane electron transfer rate, were found to be dependent on the redox potential of the bathing solutions. The overall transfer coefficient was 0.5, and it was concluded that the rate-determining step is the transfer of the semiubiquinone radical anion across the hydrophobic interior of the membrane, instead of charge transfer reactions at the membrane/electrolyte solution boundaries. The results obtained could not be understood in terms of tunneling to the neutral ubiquinone molecule residing in the bilayer.

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Potentiometric and Magnetometric Study of the Duroquinone System

Cited by 54 publications

References 0 publications

Sulfide quinone reductase (SQR) activity in Chlorobium

Sulfide quinone reductase (SQR) activity in Chlorobium

Reduction of Silver Halides and the Mechanism of Photographic Development.

Potential Dependence of Transmembrane Electron Transfer across Phospholipid Bilayers Mediated by Ubiquinone 10

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