Deficiency of subunits of Complex I and mitochondrial encephalomyopathy.
Enzymic activities of the respiratory chain and content of immunochemically detectable subunits in NADH-ubiquinone oxidoreductase (Complex I) were measured in mitochondria from the skeletal muscles of 4 patients with mitochondrial myopathy, encephalopathy, lactic acidosis, and strokelike episodes (MELAS). The rotenone-sensitive NADH-cytochrome c reductase activity was extremely decreased, ranging from 0% to 27% of the control value. In all patients, the content of subunits of Complex I was also reduced in parallel with the rotenone-sensitive NADH-cytochrome c reductase activity. It is suggested that the variation in the degree of deficiency of Complex I subunits could explain the clinical heterogeneity of patients with MELAS.
D000293:Adolescent; D001706:Biopsy; D001927:Brain Diseases / Q000473:pathology*; D002648:Child; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D007656:Ketoglutaric Acids / Q000378:metabolism; D008293:Malates / Q000378:metabolism; D008297:Male; D008931:Mitochondria, Muscle / Q000648:ultrastructure*; D009132:Muscles / Q000473:pathology; D016660:NAD(P)H Dehydrogenase (Quinone); D009468:Neuromuscular Diseases / Q000473:pathology*; D011773:Pyruvates / Q000378:metabolism; D019289:Pyruvic Acid; D011808:Quinone Reductases / Q000172:deficiency*
D007656:Ketoglutaric Acids; D008293:Malates; D011773:Pyruvates; C030298:malic acid; D019289:Pyruvic Acid; D016660:NAD(P)H Dehydrogenase (Quinone); D011808:Quinone Reductases