European Journal of Cell Biology, 85 Suppl.56(2006 March)-ElsevierGmbH-Jena-http://www.elsevier.de/ejcb          43

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Transport and ATP synthesis in mitochondria
II.Glutathione an endogenous regulatory factor for mitochondrial
phosphate/proton symport

Reinhold Kiehl

Research RKI-Institute

Abbreviations:NSPM, N'-[N"-n-nonyl-4-sulfamoyl-phenyl]-maleimide, MNT, n-mono-nonyl-thiourea; NTU, 6-nonyl-2-thiouracil; NPTU, N-phenyl-N'-nonyl-thiourea; NPA, 2-azido-4-nitrophenol; DNP, 2,4-dinitrophenol; GSH, reduced glutathione, GSSG, oxidized glutathione; RCR, respiratory control ratio. Summary: Incubation of well-coupled beef heart mitochondria with [35S] n-nonylthiouracil results in the isolation of [ 35S] thiosulfenic acid of glutathione. Calculation to 100 % inhibiting concentrations for State 4 - State 3 transition, and to 100 % inhibiting concentrations for 2.4-dinitrophenol uncoupling by n-nonylthiouracil demonstrates that almost the whole glutathione pool is involved. Under our conditions, most of the glutathione is associated with the mitochondrial membrane and no free reduced glutathione could be found. Importantly, phosphate modulates the bound and free glutathione concentrations. A mechanism suggesting glutathione as an endogenous regulatory factor (presumably at a suitable receptor site) for the mitochondrial phosphate/proton symport (and possibly for the other carriers, including transhydrogenase and H+-pumping ATPase) is presented. The effects of the sulfenyl- and thiol trapping compounds n-nonylthiouracil, thiophosphate, 2-azido-4-nitrophenol, diamide, cadmium and N'-[N"-n-nonyl-4-sulfamoylphenyl]-maleimide, as well as the high energy compound picrylacetate in this mechanism are discussed. The results are linked to cellular events and their importance for medicine (pharmacology and toxicology) is emphasized.

Key words: n-nonylthiouracil, inhibition of RCR. and uncoupling, glutathione, regulatory factor for Pi/H+ symport, regulatory model.

References:Kiehl, R., EJCB, 84 Suppl. 55 (2005 March)SI0-20, part1, and Internet-files at www. rki-i. com, www.dr-kiehl. net(free pdf- or html-files, book-chapters under publications, materials)

kiehl@rki-i.com

Jahrestagung der Deutschen Gesellschaft für Zellbiologie http://www.zellbiologie2006.de

 

 

European Joumal of Cell Biology, 85 Suppl.56 (2006 March)-ElsevierGmbH-Jena-http://www.elsevier.de/ejcb 37

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Transport and ATP synthesis in mitochondria
III. Hypothesis: Mitochondrial ATP synthesis on the phosphate/proton symport system with oxidized glutathione as a catalyst

ReinholdKiehl

Research RKI-Institute

Abbreviations:GSH, reduced glutathione; GSSG, oxidized glutathione; DNP, 2,4-dinitrophenol; NSPM, N'-[N"-n-nonyl-4-sulfamoylphenyl]-maleimide; NTU, n-nonylthiouracil, RCR, respiratory control ratio. Summary: We present as a hypothesis the mechanism for mitochondrial ATP synthesis in the 30 kDa phosphate/proton-symport system with oxidized glutathione as a catalyst. The effects of the uncoupler 2,4-dinitrophenol and arsenate in this mechanism are discussed. lt is postulated that the mitochondrial F0F1-ATPase is actually, under normal physiological conditions, a K-Pump. Coupling between ATP synthase and ATPase is suggested. Our hypothesis represents the first description of a proton-driven build-up of high-energy intermediates (activated disulfides, sulfenyl phosphate) resulting in phosphoryl transfer or transport activities.

Key words: ATP-synthesis, uncoupling, K-pump, activated disulfide, sulfenylphosphate.

References:Kiehl, R., EJCB, 84 SuppL 55 (2005 March) SI0-20, part I, DGZ- Tagung 2006, part II submitted and Internet-files at www.rki-i.com, www.dr-kiehl.net (free pdf- or html-files, book-chapters under publications, materials)

kiehl@rki-i.com

Jahrestagung der Deutschen Gesellschaft für Zellbiologie
http://www.zellbiologie2006.de

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