Dt diaphorase II. Relation to respiratory chain of intact mitochondria

Abstract-The differential effects of papaverine (Pap) and rotenone (Rot) were studied on the highly respiration-dependent contracture of guinea pig taenia coli in 40 mM potassium (40-K) medium, on isolated DT diaphorase activity and on mitochondrial respiration.The inhibition of guinea pig taenia coli to the 40-K induced tension by Rot (5 x 10-7 M) was fully reversed by the addition of a water soluble vitamin K3 (VK3) derivative or menadione sodium bisulfite (MSB). A low concentration (10-'-10-6 M) of Pap which had no effect on the 40-K induced tension inhibited the VK3 restored tension from the Rot suppression, corresponding to a Pap inhibition of the isolated DT diaphorase.Inhibition of the effective concentration of Pap to the 40-K induced tension development was never reversed by addition of VK3 or MSB. In taenia coli, both MSB and VK3 established a bypass of the Rot sensitive site on the mitochondrial respiratory chain by means of the DT diaphorase system. The difference in washout efficacy between Pap and Rot on the inhibition of 40-K induced tension was ascribed to a difference in their mitochondria) binding properties.

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“…4. These results were identical with that of VK3 in rat liver mitochondria reported elsewhere (6,8).…”

Section: Effect Of Pap and Rot On Isolated D T Diaphor•asesupporting

confidence: 92%

“…respiration of rat liver mitochondria with VK3 (6,8). The addition of MSB to the homo genate did not restore the inhibition induced by Pap.…”

Section: Effect Of Pap and Rot On Isolated D T Diaphor•asementioning

confidence: 85%

The Inhibitory Effect of Papaverine on Respiration-Dependent Contracture of Guinea Pig Taenia Coli in High-K Medium. Iii. The Differential Effect of Papaverine and Rotenone on Dt Diaphorase

Tsuda

Urakawa

Fukami

1977

Japanese Journal of Pharmacology

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“…Electrochemical behavior of semi-or dihydroquinones (quinoles) can be different (6,38). Reduced quinones can autoxidize, inducing ROS generation, or can transfer electrons to Complexes II, III, or IV, shunting ETC functions, changing redox balance in mitochondria, and working as potent antioxidants (13,23,37,46,47,49,55).…”

Section: Discussionmentioning

confidence: 99%

“…It is known that exogenous quinones can both be oxidized and reduced by ETC complexes (11,13,23,28,37,46,47,49,55). However, because they are not a primary substrate of these enzymes, the efficiency of oxidation/reduction has to be strongly dependent on the availability of primary substrates and "saturation" of electrons in the ETC (reduction states of components of ETC), just as the electron leak from ETC and superoxide production depend on the reduction states of ETC components and the proton gradient (25).…”

Section: Discussionmentioning

confidence: 99%

“…Menadione, duroquinone, and coenzyme Q 1 are capable of recovering respiratory and phosphorylating mitochondrial functions shunting ETC complexes during rotenone inhibition of respiration. Being reduced by mitochondrial DT-diaphorase, these quinones either can transfer electrons directly to Complex III, coenzyme Q, or they can play a role of succinate dehydrogenase substrates (9,10,13,23,37). Quinone derivatives are among rare compounds successfully used as therapeutic agents to treat mitochondrial diseases (5,9) and bypass the damaged sites in mitochondria.…”

Section: Introductionmentioning

confidence: 99%

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Redox regulation of mitochondrial functional activity by quinones

et al. 2016

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Quinones are among the rare compounds successfully used as therapeutic agents to correct mitochondrial diseases and as specific regulators of mitochondrial function within cells. The aim of the present study was to elucidate the redox-dependent effects of quinones on mitochondrial function. The functional parameters [respiratory activity, membrane potential, and reactive oxygen species (ROS) generation] of isolated rat liver mitochondria and mitochondria in intact cells were measured in the presence of eight exogenously applied quinones that differ in lipophilicity and one-electron reduction potential. The quinones affected the respiratory parameters of mitochondria, and dissipated the mitochondrial membrane potential as well as influenced (either decreased or enhanced) ROS generation, and restored the electron flow during electron transport chain inhibition. The stimulation of ROS production by juglone and 2,5-di-tert-butyl-1,4-benzoquinone was accompanied by a decrease in the acceptor control and respiration control ratios, dissipation of the mitochondrial membrane potential and induction of the reverse electron flow under succinate oxidation in isolated mitochondria. Menadione and 2,3,5-trimethyl-1,4-benzoquinone, which decreased the mitochondrial ROS generation, did not affect the mitochondrial potential and, vice versa, were capable of restoring electron transport during Complex I inhibition. In intact C6 cells, all the quinones, except for coenzyme Q 10 , decreased the mitochondrial membrane potential. Juglone, 1,4-benzoquinone, and menadione showed the most pronounced effects. These findings indicate that quinones with the reduction potential values E 1/2 in the range from −99 to −260 mV were effective redox regulators of mitochondrial electron transport.

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Some Aspects of Enzyme Reactions in Heterogeneous Systems

Packer

1970

Advances in Enzymology - And Related Areas of Molecular Biology

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Dt diaphorase II. Relation to respiratory chain of intact mitochondria

Cited by 75 publications

References 20 publications

The Inhibitory Effect of Papaverine on Respiration-Dependent Contracture of Guinea Pig Taenia Coli in High-K Medium. Iii. The Differential Effect of Papaverine and Rotenone on Dt Diaphorase

The Inhibitory Effect of Papaverine on Respiration-Dependent Contracture of Guinea Pig Taenia Coli in High-K Medium. Iii. The Differential Effect of Papaverine and Rotenone on Dt Diaphorase

Redox regulation of mitochondrial functional activity by quinones

Some Aspects of Enzyme Reactions in Heterogeneous Systems

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