title: Molecular basis of mitochondrial myopathies: polypeptide analysis in complex-I deficiency.
abstract: Clinical and biochemical data are reported for three patients with mitochondrial myopathy. One patient presented only with exercise-induced muscle weakness, whereas the other two showed signs of multisystem disease. Polarographic determination of oxygen uptake in skeletal muscle mitochondria suggested complex-I (nicotinamide adenine dinucleotide [reduced] ubiquinone oxidoreductase) deficiency. Sodium dodecyl sulphate polyacrylamide gel electrophoresis and immunoblotting with antibody to the holoenzyme of complex-I and specific antibodies to certain of the Fe-S subunits of complex-I showed a relatively normal profile in the least affected patient and a generalised reduction in the intensities of all crossreacting bands in the other two patients. The most severely affected patient also showed a disproportionate and pronounced reduction in the 24 K Fe-S subunit. Clinical severity of muscle involvement correlated with the biochemical deficiency as determined polarographically and with the immunoblot appearances.
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D008931:Mitochondria, Muscle / Q000378:metabolism*; D009135:Muscular Diseases / Q000378:metabolism* / Q000503:physiopathology; D016660:NAD(P)H Dehydrogenase (Quinone); D010101:Oxygen Consumption; D011808:Quinone Reductases / Q000172:deficiency*
chemical_list: D016660:NAD(P)H Dehydrogenase (Quinone); D011808:Quinone Reductases