Kuznetsov 1997 Biochim Biophys Acta

Kuznetsov AV, Winkler K, Kirches E, Lins H, Feistner H, Kunz WS (1997) Application of inhibitor titrations for the detection of oxidative phosphorylation defects in saponin-skinned muscle fibers of patients with mitochondrial diseases. Biochim Biophys Acta 1360: 142-150.

» PMID: 9128179

Kuznetsov AV, Winkler K, Kirches E, Lins H, Feistner H, Kunz WS (1997) Biochim Biophys Acta

Abstract: Inhibitor titrations were applied to characterize functional changes in mitochondrial energy metabolism in the skeletal muscle of patients with mitochondrial diseases. For this we titrated the maximal mitochondrial respiration rate of saponin-skinned muscle fibers isolated from the skeletal muscle biopsy with the specific inhibitors of mitochondrial oxidative phosphorylation complexes I, IV and V-rotenone, azide and oligomycin. For three patients with deletions of mitochondrial DNA and one patient with a complex I deficiency the titrations revealed at rather normal respiration activities of saponin-skinned fibers significant differences to healthy controls: (i) The inhibitor titration curves of the affected enzyme were much steeper and (ii) for almost complete inhibition of respiration a smaller amount of the inhibitor is necessary. The detailed analysis of the titration curves within the framework of metabolic control theory indicated elevated flux control coefficients of the respective complex of respiratory chain. On the other hand, for one patient with a mitochondrial DNA depletion syndrome, decreased respiration activities of skinned fibers but no redistribution of flux control was observed. We conclude, therefore, that application of inhibitor titrations and the quantitative description of the titration curve can be a valuable approach to elucidate functional defects of mitochondrial oxidative phosphorylation. • Keywords: Mitochondrial disease; Saponin-skinned muscle fiber; Inhibitor titration; Metabolic control analysis; Flux control coefficient

Labels: MiParea: Respiration, mt-Medicine, Patients  Pathology: Inherited 

Tissue;cell: Skeletal muscle  Preparation: Permeabilized tissue  Enzyme: Complex I, Complex III, Complex IV; Cytochrome c Oxidase"Complex IV; Cytochrome c Oxidase" is not in the list (Adenine nucleotide translocase, Complex I, Complex II;succinate dehydrogenase, Complex III, Complex IV;cytochrome c oxidase, Complex V;ATP synthase, Inner mt-membrane transporter, Marker enzyme, Supercomplex, TCA cycle and matrix dehydrogenases, ...) of allowed values for the "Enzyme" property., Complex V; ATP Synthase"Complex V; ATP Synthase" is not in the list (Adenine nucleotide translocase, Complex I, Complex II;succinate dehydrogenase, Complex III, Complex IV;cytochrome c oxidase, Complex V;ATP synthase, Inner mt-membrane transporter, Marker enzyme, Supercomplex, TCA cycle and matrix dehydrogenases, ...) of allowed values for the "Enzyme" property.  Regulation: Inhibitor, Threshold;excess capacity  Coupling state: OXPHOS 

HRR: Oxygraph-2k