Inhibition of Complex I by Ca2+Reduces Electron Transport Activity and the Rate of Superoxide Anion Production in Cardiac Submitochondrial Particles†

Biochemistry ◽  
2007 ◽  
Vol 46 (5) ◽  
pp. 1350-1357 ◽  
Author(s):  
Satoshi Matsuzaki ◽  
Luke I. Szweda
Keyword(s):  
Electron Transport ◽  
Superoxide Anion ◽  
Complex I ◽  
Transport Activity ◽  
Submitochondrial Particles ◽  
Superoxide Anion Production ◽  
Anion Production ◽  
Electron Transport Activity

scholarly journals The specificity of mitochondrial complex I for ubiquinones

1996 ◽  
Vol 313 (1) ◽  
pp. 327-334 ◽  
Author(s):  
Mauro ESPOSTI DEGLI ◽  
Anna NGO ◽  
Gabrielle L. McMULLEN ◽  
Anna GHELLI ◽  
Francesca SPARLA ◽  
...  
Keyword(s):  
Membrane Potential ◽  
Electron Transport ◽  
Complex I ◽  
Reductase Activity ◽  
Redox Activity ◽  
Mitochondrial Complex I ◽  
Transport Activity ◽  
Mitochondrial Complex ◽  
Potential Generation ◽  
Electron Transport Activity

We report the first detailed study on the ubiquinone (coenzyme Q; abbreviated to Q) analogue specificity of mitochondrial complex I, NADH:Q reductase, in intact submitochondrial particles. The enzymic function of complex I has been investigated using a series of analogues of Q as electron acceptor substrates for both electron transport activity and the associated generation of membrane potential. Q analogues with a saturated substituent of one to three carbons at position 6 of the 2,3-dimethoxy-5-methyl-1,4-benzoquinone ring have the fastest rates of electron transport activity, and analogues with a substituent of seven to nine carbon atoms have the highest values of association constant derived from NADH:Q reductase activity. The rate of NADH:Q reductase activity is potently but incompletely inhibited by rotenone, and the residual rotenone-insensitive rate is stimulated by Q analogues in different ways depending on the hydrophobicity of their substituent. Membrane potential measurements have been undertaken to evaluate the energetic efficiency of complex I with various Q analogues. Only hydrophobic analogues such as nonyl-Q or undecyl-Q show an efficiency of membrane potential generation equivalent to that of endogenous Q. The less hydrophobic analogues as well as the isoprenoid analogue Q-2 are more efficient as substrates for the redox activity of complex I than for membrane potential generation. Thus the hydrophilic Q analogues act also as electron sinks and interact incompletely with the physiological Q site in complex I that pumps protons and generates membrane potential.

scholarly journals Localization of superoxide anion production to mitochondrial electron transport chain in 3-NPA-treated cells

Mitochondrion ◽  
2006 ◽  
Vol 6 (5) ◽  
pp. 235-244 ◽  
Author(s):  
Attila Bacsi ◽  
Mitchell Woodberry ◽  
William Widger ◽  
John Papaconstantinou ◽  
Sankar Mitra ◽  
...  
Keyword(s):  
Electron Transport ◽  
Superoxide Anion ◽  
Electron Transport Chain ◽  
Mitochondrial Electron Transport Chain ◽  
Superoxide Anion Production ◽  
Transport Chain ◽  
Anion Production

Lactate and P o 2 Modulate Superoxide Anion Production in Bovine Cardiac Myocytes

Circulation ◽  
1997 ◽  
Vol 96 (2) ◽  
pp. 614-620 ◽  
Author(s):  
Kamal M. Mohazzab-H. ◽  
Pawel M. Kaminski ◽  
Michael S. Wolin
Keyword(s):  
Cardiac Myocytes ◽  
Superoxide Anion ◽  
Superoxide Anion Production ◽  
Anion Production

Photoinhibition of Electron Transport Activity of Photosystem II in Isolated Thylakoids Studied by Thermoluminescence and Delayed Luminescence

1988 ◽  
Vol 43 (11-12) ◽  
pp. 871-876 ◽  
Author(s):  
Imre Vass ◽  
Narendranath Mohanty ◽  
Sándor Demeter
Keyword(s):  
Electron Transport ◽  
Photosystem Ii ◽  
Photosystem I ◽  
Half Life ◽  
Delayed Luminescence ◽  
Transport Activity ◽  
Primary Target ◽  
Electron Transport Activity ◽  
The Stability ◽  
Spinach Thylakoids

Abstract The effect of photoinhibition on the primary (QA) and secondary (QB) quinone acceptors of photosystem I I was investigated in isolated spinach thylakoids by the methods of thermoluminescence and delayed luminescence. The amplitudes of the Q (at about 2 °C) and B (at about 30 °C) thermoluminescence bands which are associated with the recombination of the S2QA- and S2QB charge pairs, respectively, exhibited parallel decay courses during photoinhibitory treatment. Similarly, the amplitudes of the flash-induced delayed luminescence components ascribed to the recombination of S20A and S2OB charge pairs and having half life-times of about 3 s and 30 s, respectively, declined in parallel with the amplitudes of the corresponding Q and B thermoluminescence bands. The course of inhibition of thermoluminescence and delayed luminescence intensity was parallel with that of the rate of oxygen evolution. The peak positions of the B and Q thermoluminescence bands as well as the half life-times of the corresponding delayed luminescence components were not affected by photoinhibition. These results indicate that in isolated thylakoids neither the amount nor the stability of the reduced OB acceptor is preferentially decreased by photoinhibition. We conclude that either the primary target of photodamage is located before the O b binding site in the reaction center of photosystem II or QA and OB undergo simultaneous damage.

Sign in / Sign up

Export Citation Format

Share Document