Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

(1) Biopsies from the gastrocnemius muscle of patients with Duchenne dystrophy were partitioned into a myofibrillar plus nuclear fraction, a mitochondrial fraction and a supernatant fraction. The fractions were assayed for mitochondrial enzymes and protein, in order to obtain information about the integrity of mitochondrial structure and function. Muscles from boys and adults without neuromuscular disease were treated likewise. (2) In adults, muscle possesses a significantly higher specific activity (on protein basis) of monoamine oxidase and rotenone-insenitive NADH-cytochrome c reductase (RINCR) than in boys. In childhood, monoamine oxidase activity increases with age. At the age of 5 yr, the specific activity is 50% of the adult value. RINCR activity is constant in childhood. With adolescence it increases from 20 +/- 2 (SEM) to 35 +/- 6 mumoles cytochrome c reduced per min per g protein, and it remains at this level. Palmitoyl-CoA synthetase activity remains constant with age. (3) In Duchenne dystrophy the extractable protein content from muscle is decreased to 75%. The specific activities of the matrix enzymes propionyl-CoA carboxylase and glutamate dehydrogenase are 1.8 and 2.8 times increased, the inner membrane enzyme cytochrome c oxidase is 2.8 times increased, the inner membrane enzyme cytochrome c oxidase is 2.8 times increased. Of the outer membrane enzymes RINCR is 2.0 times increased, while palmitoyl-CoA synthetase is not changed in acitivity. In Duchenne dystrophy monoamine oxidase activity also increases with age. In part this may be due to mitochondria from adipose tissue and macrophages, which are increasingly present in older patients. The specific activities of enzymes with a predominant cytosolic localisation, creatine kinase and adenylate kinase, are increased by a factor of 1.5 and 1.7. (4) The subcellular distribution of the studied enzymes in human skeletal muscle was found to be similar as in animal studies. In mitochondrial fractions from Duchenne patients the recoveries of the following enzymes are decreased: glutamate dehydrogenase (from 25 to 9%), creatine kinase (1.1-0.66%), adenylate kinase (0.44-0.22%), hexokinase (7.1-2.7%), monoamine oxidase (36-21%), RINCR (30-17%), and palmitoyl-CoA synthetase (40-21%). The recoveries of last 3 mitochondrial outer membrane enzymes in the supernatant fractions are correspondingly increased. These results indicate an increased fragility of the mitochondrial membranes in dystrophic muscles. (5) The reported changes are clearly evident in a one-year-old patient, which indicates that the mitochondria are involved early in the disease process.
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PMID:Early changes of muscle mitochondria in Duchenne dystrophy. Partition and activity of mitochondrial enzymes in fractionated muscle of unaffected boys and adults and patients. 624 85

In carrying out a new study of nucleotide concentrations in dystrophic muscle, we utilized myosin as a reference base. In nine control vastus lateralis muscle samples, nucleotide concentrations were 105 +/- 11 (SEM) moles of adenosine triphosphate (ATP) and 446 +/- 57 (SEM) nmoles of creatine phosphate (CP) per milligram of myosin. In seven Duchenne dystrophic vastus lateralis muscle samples, nucleotide concentrations were 127 +/- 25 (SEM) nmoles of ATP and 462 +/- 119 (SEM) moles of CP per milligram of myosin. The CP:ATP ratio of 3.6 +/- 0.367 from Duchenne muscle was not significantly different from normal, 4.32 +/- 0.243 ((p less than 0.20). In addition, myokinase activity, which is automatically assayed in these assays, was significantly increased in the Duchenne samples (p less than 0.10). The percent of myosin per total protein in the Duchenne biopsies was also diminished by 29% (p less than 0.01). These studies suggest that ATP and CP concentrations are not decreased in Duchenne dystrophic muscle when expressed in relation to the amount of contractile protein.
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PMID:Duchenne muscular dystrophy: adenosine triphosphate and creatine phosphate content in muscle. 719 21

In this study we describe the molecular identification, kinetic characterization and biochemical properties of an E-NTPDase and an 5'-nucleotidase in Walker 256 cells. For the ATP, ADP and AMP hydrolysis there were optimum pH in the range 6.5-8.0, and absolute requirement for divalent cations (Mg(2+)>Ca(2+)). A significant inhibition of ATP and ADP hydrolysis was observed in the presence of high concentrations of sodium azide and 0.5 mM of Gadolinium chloride. These activities were insensitive to ATPase, adenylate kinase and alkaline phosphatase classical inhibitors. The K(m) values were 464.2+/-86.6 microM (mean+/-SEM, n=4), 137.0+/-31 microM (mean+/-SEM, n=5) and 44.8+/-10.2 microM (mean+/-SEM, n=4), and V(max) values were 655.0+/-94.6 (mean+/-SEM, n=4), 236.3+/-27.2 (mean+/-SEM, n=5) and 177.6+/-13.8 (mean+/-SEM, n=5) nmol of inorganic phosphate min(-1) mg of protein(-1) for ATP, ADP and AMP, respectively. Using RT-PCR analysis we identified the mRNA of two members of the ecto-nucleoside triphosphate diphosphohydrolase family (NTPDase 2 and 5) and a 5'-nucleotidase. The presence of NTPDases and 5'-nucleotidase enzymes in Walker 256 tumor cells may be important to regulate the ratio adenine nucleotides/adenine nucleoside extracellularly, therefore motivating tumor growth.
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PMID:Nucleotide metabolizing ecto-enzymes in Walker 256 tumor cells: molecular identification, kinetic characterization and biochemical properties. 1716 79