Difference between revisions of "Kiss 2014 FASEB J"
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|year=2014 | |year=2014 | ||
|journal=FASEB J | |journal=FASEB J | ||
|abstract=Substrate-level phosphorylation mediated by succinyl-CoA ligase in the mitochondrial matrix produces highenergy | |abstract=Substrate-level phosphorylation mediated by succinyl-CoA ligase in the mitochondrial matrix produces highenergy phosphates in the absence of oxidative phosphorylation. Furthermore, when the electron transport chain is dysfunctional, provision of succinyl-CoA by the Ξ±-ketoglutarate dehydrogenase complex (KGDHC) is crucial for maintained operation of succinyl-CoA ligase yielding ATP, preventing the adenine nucleotide translocase from reversing. Here we addressed the source of NAD+ supply for KGDHC under anoxic conditions and inhibition of Complex I. Using pharmacological tools, specific substrates and by examining tissues from pigeon liver exhibiting no diaphorase activity we show that mitochondrial diaphorases in the mouse liver contributed up to 81 % to the NAD+ pool during respiratory inhibition. Under these conditions, KGDHC function, essential for the provision of succinyl-CoA to succinyl-CoA ligase, is supported by NAD+ derived from diaphorases. By this, diaphorases contribute to the maintenance of substrate-level phosphorylation during respiratory inhibition, which is manifested in the forward operation of adenine nucleotide translocase. Finally, we show that reoxidation of the reducible substrates for the diaphorases is mediated by Complex III of the respiratory chain. | ||
phosphates in the absence of oxidative phosphorylation. Furthermore, when the electron transport chain | |||
is dysfunctional, provision of succinyl-CoA by the Ξ±-ketoglutarate dehydrogenase complex (KGDHC) is crucial | |||
for maintained operation of succinyl-CoA ligase yielding ATP, preventing the adenine nucleotide translocase | |||
from reversing. Here we addressed the source of NAD+ supply for KGDHC under anoxic conditions and | |||
inhibition of | |||
liver exhibiting no diaphorase activity we show that mitochondrial diaphorases in the mouse liver contributed | |||
up to 81% to the NAD+ pool during respiratory inhibition. Under these conditions, KGDHC function, essential | |||
for the provision of succinyl-CoA to succinyl-CoA ligase, is supported by NAD+ derived from diaphorases. By | |||
this, diaphorases contribute to the maintenance of substrate-level phosphorylation during respiratory inhibition, | |||
which is manifested in the forward operation of adenine nucleotide translocase. Finally, we show that reoxidation | |||
of the reducible substrates for the diaphorases is mediated by | |||
|keywords=Succinyl-CoA ligase, Adenine nucleotide translocase, DT-diaphorase, Reducing equivalent, Safranin | |keywords=Succinyl-CoA ligase, Adenine nucleotide translocase, DT-diaphorase, Reducing equivalent, Safranin | ||
|mipnetlab=HU Budapest Chinopoulos C,Β HU Budapest Tretter L | |mipnetlab=HU Budapest Chinopoulos C,Β HU Budapest Tretter L | ||
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|couplingstates=LEAK, OXPHOS | |couplingstates=LEAK, OXPHOS | ||
|instruments=Oxygraph-2k, O2k-Fluorometer, TPP | |instruments=Oxygraph-2k, O2k-Fluorometer, TPP | ||
|additional=Safranin | |additional=Safranin, MitoFit2022rTCA | ||
}} | }} |
Revision as of 11:08, 14 February 2022
Kiss G, Konrad C, Pour-Ghaz I, Mansour JJ, NΓ©meth B, Starkov AA, Adam-Vizi V, Chinopoulos C (2014) Diaphorases provide NAD+ in anoxia. FASEB J 28:1682-97. |
Kiss G, Konrad C, Pour-Ghaz I, Mansour JJ, Nemeth B, Starkov AA, Adam-Vizi V, Chinopoulos C (2014) FASEB J
Abstract: Substrate-level phosphorylation mediated by succinyl-CoA ligase in the mitochondrial matrix produces highenergy phosphates in the absence of oxidative phosphorylation. Furthermore, when the electron transport chain is dysfunctional, provision of succinyl-CoA by the Ξ±-ketoglutarate dehydrogenase complex (KGDHC) is crucial for maintained operation of succinyl-CoA ligase yielding ATP, preventing the adenine nucleotide translocase from reversing. Here we addressed the source of NAD+ supply for KGDHC under anoxic conditions and inhibition of Complex I. Using pharmacological tools, specific substrates and by examining tissues from pigeon liver exhibiting no diaphorase activity we show that mitochondrial diaphorases in the mouse liver contributed up to 81 % to the NAD+ pool during respiratory inhibition. Under these conditions, KGDHC function, essential for the provision of succinyl-CoA to succinyl-CoA ligase, is supported by NAD+ derived from diaphorases. By this, diaphorases contribute to the maintenance of substrate-level phosphorylation during respiratory inhibition, which is manifested in the forward operation of adenine nucleotide translocase. Finally, we show that reoxidation of the reducible substrates for the diaphorases is mediated by Complex III of the respiratory chain. β’ Keywords: Succinyl-CoA ligase, Adenine nucleotide translocase, DT-diaphorase, Reducing equivalent, Safranin
β’ O2k-Network Lab: HU Budapest Chinopoulos C, HU Budapest Tretter L
Labels: MiParea: Respiration
Organism: Mouse
Tissue;cell: Liver
Preparation: Isolated mitochondria
Coupling state: LEAK, OXPHOS
HRR: Oxygraph-2k, O2k-Fluorometer, TPP
Safranin, MitoFit2022rTCA