Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0016719 (Friedreich's ataxia)
 2,098 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have measured the activity of malic enzyme NADP+ dependent in the nuclear, mitochondrial, lysosomal and cytosolic fractions of cultured skin fibroblasts from twelve patients with Friedreich's ataxia and nine control subjects. Hexosaminidase, cytochrome-C-oxidase, lactate dehydrogenase and malic enzyme NAD+ dependent were used as marker enzymes. The activity of malic enzyme NADP+ dependent was not significantly reduced in the mitochondrial fraction of patients with Friedreich's ataxia as compared with controls. When corrected for possible contamination between mitochondrial and cytosolic fractions, malic enzyme NADP+ dependent activity was still not significantly reduced in patients with Friedreich's ataxia. Unless critical methodological differences were overlooked in this or previously published studies, we conclude that mitochondrial malic enzyme deficiency is not the primary genetic defect underlying Friedreich's ataxia.
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PMID:Friedreich's ataxia: malic enzyme activity in cellular fractions of cultured skin fibroblasts. 650 17

Malic enzymes were studied in skeletal muscle from seven patients with Friedreich's ataxia (FA) and nine controls. Muscle contained three different malic enzymes. There were two strictly NADP+-dependent enzymes, one in the cytosol and one in mitochondria. These two enzymes are not allosteric. In FA muscle, activity of the mitochondrial NADP+-linked enzyme was significantly low and the cytosol NADP+-linked enzyme was significantly increased. A third malic enzyme, NAD+(P)-dependent, was found in the mitochondrial fraction. That enzyme had allosteric properties, and its activity was about the same in FA and control muscle.
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PMID:Skeletal muscle NAD+(P) and NADP+-dependent malic enzyme in Friedreich's ataxia. 668 15

Polarographic assays of oxidative phosphorylation in muscle mitochondria indicated abnormal pyruvate-malate metabolism in Friedreich ataxia (FA). Pursuing this clue, more specific assays were performed. Mitochondrial malic enzyme (MEm; malate: NADP+ oxidoreductase) specific activity was 10% of controls in fibroblasts from eight FA patients (p less than 0.0001). Cytosolic malic enzyme was modestly increased in FA fibroblasts. Mitochondrial and cytosolic malate dehydrogenase and aspartate aminotransferase, and malate transport on the dicarboxylate and alpha-ketoglutarate carriers were normal in fibroblasts or leukocytes. MEm activity is normally highest in the nervous system and heart is important in regulating carbohydrate metabolism. MEm deficiency could cause FA; further studies are required to substantiate this hypothesis.
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PMID:Friedreich ataxia: III. Mitochondrial malic enzyme deficiency. 719 31