Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.6.99.3 (diaphorase)
 5,903 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Mitoplasts were prepared from 3-h ischemic livers in an attempt to define the structural alterations in the inner membrane that may account for the functional deficiencies of ischemic mitochondria. Mitoplasts from both control and ischemic livers had similar specific activities of cytochrome oxidase and succinate-cytochrome c reductase. With both preparations, the specific activity of rotenone-insensitive NADH-cytochrome c reductase was 10-fold lower than in the mitochondria from which they were prepared. Ischemic mitoplasts had no respiratory control with ADP, and had a slightly reduced phospholipid to protein ratio and an increased cholesterol to protein ratio. As a result, the cholesterol to phospholipid molar ratio was increased from the control of 0.04 to 0.08. There were also differences in the content of individual phospholipid species. Phosphatidylcholine increased by 15%, while cardiolipin decreased by 60%. There were increases in sphingomyelin and in the lysophospholipids of phosphatidylcholine, ethanolamine, and cardiolipin. Pretreatment with chlorpromazine did not prevent these changes. Linoleic acid was decreased by 35% in ischemic phospholipids, and the content of free fatty acids was increased 4-fold. Electron spin resonance spectroscopy of mitoplasts spin labeled with either 5- or 12-doxyl stearic acid revealed an increased molecular order (decreased fluidity) of ischemic inner mitochondrial membranes consistent with the increased cholesterol to phospholipid ratio. The data indicate activation of a phospholipase A in ischemic mitochondria with the resulting accumulation of products of lipid hydrolysis. This conclusion further emphasizes the close similarity between the structural and functional consequences of ischemia in the intact animal and the effect on isolated mitochondria of the activation of the endogenous phospholipase A. In both cases the major functional alterations are attributable to changes in the permeability of the inner mitochondrial membrane induced by the accumulation of lysophospholipids.
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PMID:Structural alterations of the inner mitochondrial membrane in ischemic liver cell injury. 298 20

The photosynthetic chromatophore membranes of Rhodopseudomonas capsulata were fused with liposomes to investigate the effects of lipid dilution on energy transfer between the bacteriochlorophyll-protein complexes of this membrane. Phosphatidylcholine-containing liposomes were mixed with chromatophores at pH 6.0 to 6.2, and the mixture was fractionated on discontinuous sucrose gradients into four membrane fractions with lipid-to-protein ratios that varied 11-fold. Freeze-fracture electron microscopy revealed that the fractions contained closed vesicles formed by the fusion of liposomes to chromatophores. Particles with 9-nm diameters on the P fracture faces did not appear to change in size with increasing lipid content, but the number of particles per membrane area decreased proportionally with increases in the lipid-to-protein ratio. The bacteriochlorophyll-to-protein ratios, electrophoretic polypeptide profiles on sodium dodecyl sulfate-polyacrylamide gels, and light-induced absorbance changes at 595 nm caused by photosynthetic reaction centers were not altered by fusion. The relative fluorescence emission intensities due to the B875 light-harvesting complex increased significantly with increasing lipid content, but no increases in fluorescence due to the B800-B850 light-harvesting complex were observed. Electron transport rates, measured as succinate-cytochrome c reductase activities, decreased with increased lipid content. The results indicate an uncoupling of energy transfer between the B875 light-harvesting and reaction center complexes with lipid dilution of the chromatophore membrane.
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PMID:Fusion of liposomes and chromatophores of Rhodopseudomonas capsulata: effect on photosynthetic energy transfer between B875 and reaction center complexes. 399 75

An influence of corticosteroids on the phospholipid composition of several tissues has been demonstrated previously. Increases in the activity of rat liver microsomal cytochrome c reductase and aryl hydrocarbon hydroxylase after corticoid administration were also demonstrated. The phospholipid composition of liver microsomes is now reported to be altered by similar corticosteroid treatment. Phosphatidylcholine, phosphatidylethanolamine, and sphingomyelin levels in rat liver microsomes were decreased significantly after in vivo cortisol administration. The levels of palmitic, stearic, oleic, linoleic, and arachidonic acids in phosphatidylcholine and of palmitic acid in phosphatidylserine-phosphatidylinositol were also affected. Cholesterol was increased after adrenalectomy and decreased to control levels after the administration of cortisol. Some of the microsomal enzymes which are affected by corticosteroids or adrenalectomy are known to require phospholipids for full activity. The alteration of enzyme activities and membrane phospholipid composition by similar dosage schedules of corticosteroids suggests a possible relation between the two effects. By affecting the lipid composition of the membranes, corticosteroids may regulate or modulate the activity of the lipid-requiring enzyme systems.
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PMID:Corticosteroid-induced lipid changes in rat liver microsomes. 726 26

The membrane components of the castor bean spherosomes were characterized. The storage triacylglycerols of isolated spherosomes were extracted with diethyl ether, and the membrane was isolated by sucrose gradient centrifugation. It had an apparent equilibrium density of 1.12 grams per cubic centimeter, and possessed an antimycin A-insensitive NADH cytochrome c reductase and an acid lipase. Phosphatidylcholine, phosphatidylethanolamine, and phosphatidylinositol in roughly equal amounts were the major phospholipids. The membrane proteins were resolved into several major and minor protein bands of molecular weights ranging from 10,000 to 70,000 by acrylamide gel electrophoresis, and the protein pattern in the gel was different from those of the endoplasmic reticulum, mitochondrial, and glyoxysomal membranes.The varying amounts of spherosomal components in the seed were followed throughout seed maturation and germination. A striking similarity existed in the developmental pattern of each of the spherosomal components. This finding suggests that the spherosome is synthesized and degraded as one individual unit. The spherosomes isolated from maturing seeds exhibited rapid hydrolysis of the storage lipid in vitro, thus raising the problem of cellular control in preventing in vivo autolysis of the spherosomes during seed maturation.
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PMID:Spherosomes of Castor Bean Endosperm: MEMBRANE COMPONENTS, FORMATION, AND DEGRADATION. 1666 55