Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:Q8NEX9 (reductase)
 26,410 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Histochemical techniques have been employed to characterize enzymatic activity in the mesocoxal muscles of the cockroach, Periplaneta americana. Through our studies of the enzymes myosin-ATPase, NADH reductase, succinic dehydrogenase (SDH), and lactic dehydrogenase (LDH), we were able to classify fibers within these muscles according to criteria established for muscle fibers of vertebrates. Many of the mesocoxal muscles possess two different and distinct populations of fibers, whereas the remaining muscles are homogeneous with respect to their constituent fibers. The data presented here indicate biochemical heterogeneity for muscles of differing structural and functional features and possible neurotrophic influences upon oxidative enzymes and myosin-ATPase isozymes.
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PMID:Enzyme histochemistry of the mesocoxal muscles of Periplaneta americana. 3 9

Exposure of rat brain Na+ + K+-ATPase (ATP phosphohydrolase E.C. 3.6.1.3) to concentrations of cassaine greater than 1 x 10(-4) M resulted in a poorly reversible inhibition of this enzyme. Inhibition did not require the presence of ATP and developed rapidly, but the final amount of inhibition observed was independent of time. The amount of inhibition observed at a given concentration of cassaine was reduced by increasing the concentration of membranes in the system. The inhibition of Na+ + K+-ATPase activity was associated with equivalent inhibition of the phosphorylation and (3H)-ouabain binding reactions of this enzyme, while the uninhibited enzyme was apparently kinetically normal. Concentrations of cassaine which produced this stable inhibition of Na+ + K+-ATPase had no effect on the Mg2+-activated ATPase or the NADH cytochrome-c-reductase activities of crude rat brain microsomal preparations. Cassaine inhibited the cholinesterase activity of rat brain microsomes with a Ki of about 5 x 10(-5) M, but his inhibition was fully reversible. The poorly reversible inhibitory actions of cassaine, thus, appeared specific for Na+ + K+-ATPase. Because this stable pattern of inhibition of the Na+ + K+-ATPase by cassaine required drug concentrations at least one hundred-fold greater than those which produce positive inotropic effects, it appears unlikely that this pattern of Na+ + K+-ATPase inhibition is involved in the cardiotonic actions of this drug.
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PMID:Studies on the stable inhibition of Na+ + K+-ATPase by cassaine. 13 Feb 44

1. Oxidative phosphorylation was reconstituted with a mitochondrial proton pump (oligomycin-sensitive ATPase) and segments of the oxidation chain (cytochrome oxidase or DPNH-Q1 reductase). A proton pump of bacteriorhodopsin substituted for the respiratory chain components, giving rise to light-induced ATP formation. 2. Since oxidative phosphorylation has thus become a special case of the problem of ion translocation in general, we have investigated and reconsituted other pumps. The reconstituted Ca++ pump of sarcoplasmic reticulum consists of two factors, the Ca++-dependent ATPase and a heat-stable coupling factor. 3. Other information obtained from reconstitution experiments include the role of asymmetry in organized membranes and the specificity of protein-phospholipid interaction. 4. Purified preparations of Ca++-ATPase catalyze the formation of ATP from Pi and ADP in a stepwise reaction stoichiometric with the enzyme and dependent on Ca++.
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PMID:Resolution and reconstitution of ion-transport systems. 13 Aug 18

The ATPase reaction and its pH lability demonstrate three fiber types in the adult mouse gastrocnemius; Type I (light staining with alkaline preincubation and dark with acid preincubation), Type IIA (dark after alkaline preincubation), type IIB (dark after alkaline and acid preincubation). The SDH and NADH-tetrazolium reductase reactions also demonstrate three types of fibers; those low (A), intermediate (B) or high (C) in oxidative enzyme activity. However, the use of both procedures in serial sections demonstrates that four different combinations occur; the IIB fibers are high in SDH activity, the I fibers are intermediate in SDH enzyme activity, while the IIA fibers are either low or intermediate in SDH activity. These fiber types are present within the gastrocnemius muscle in a distinct pattern of zones. The predominant fiber type, located in the superficial half of the muscle, is the IIA (A) fiber which is high in ATPase and low in SDH activity. This is consistent with the fact that the gastrocnemius is generally considered a white, fast muscle. The IIB and I fibers are fewer in number and are located deeper in the muscle.
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PMID:Skeletal muscle fiber types in the adult mouse. 13 38

The activity of the erythrocyte enzymes: glucose-6-phosphate dehydrogenase, pyruvate kinase, glutathion reductase and ATPase were measured in 8 patients with untreated myelomatosis. Glucose-6-phosphate dehydrogenase was significantly increased. Glucose-6-phosphate dehydrogenase values were negatively correlated with the glomerular filtration rate as measured by 51Cr-EDTA clearance. The results support the existence of a shortened red cell survival in peripheral blood related to the degree of renal insufficiency.
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PMID:Erythrocyte enzymes in myelomatosis. 13 47

An electrophilous inhibitor, p-(N,N-di-2-chloroethyl)amino-phenylacetic acid (I), specifically disturbs the mechanism of respiration and phosphorylation coupling in mitochondria. I inhibits respiration and ATPase activity in intact mitochondria and does not affect these processes in mitochondria and submitochondrial particles with partially or completely impaired coupling system. The data obtained show that I inhibits protonophoric function of NADH-ferricianide reductase from submitochondrial particles soluble ATPases from bovine heart and Micrococcus lysodeikticus mitochondria adsorded on octane water interface and has no effect on respective enzymes in water solutions. Cation-transferring enzymes are shown to behave with respect to the inhibitor on lipid water interface like respective enzymes in intact mitochondria, while in water solutions they behave like those in systems with the impaired coupling mechanism. Effect of I on protonophoric function of oligomycin-sensitive ATPase and bacteriorhodopsin plaques isolated from Halobacterium halobium is also studied. It is shown that the precence or the absence of I effect is due to a nature of lipid in the enzymatic complex. I is found also to inhibit specifically the transport of Ca2+ from water to octane in the presence of Ca2+-ATP-ase from rabbit sarcoplasmic reticulum.
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PMID:[Mechanism of action of the specific inhibitor of respiration and phosphorylation in mitochondria--n-(N,N-di-2-chlorethyl)aminophenylacetic acid]. 13 99

Human erythrocytes from healthy male donors were fractionated with respect to in vivo age by simple centrifugation in order to characterize changes in the functional integrity of the membrane during the life-span of the cell. The three enzymes, Na/K-ATPase, glyceraldehyde-3-phosphate dehydrogenase and NADH-ferricyanide reductase, were found not to change with age, but significant age-dependent decreases were observed in the cases of acetylcholinesterase, phosphoglycerate kinase, purine nucleoside phosphorylase, adenylate kinase, Mg-ATPase and alkaline phosphatase. The possibility that these changes were attributable to mechanisms other than age-related inactivation, such as reticulocyte contamination, differential resealing and crypticity, was investigated. Only the decrease in acetylcholinesterase could be explained wholly in terms of reticulocyte contamination. A decrease in membrane integrity on ageing was observed, which accounted for approximately half the change in alkaline phosphatase and may have contributed to the other enzyme activity changes. This membrane integrity effect masked a real decrease in the highly cryptic NADH-ferricyanide reductase, this decrease being apparent only after total disaggregation of the membrane with nonionic surfactant.
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PMID:Changes in the activities of some membrane-associated enzymes during in vivo ageing of the normal human erythrocyte. 14 40

A histochemical analysis has been performed of the activity of myofibrillar ATPase, NADH2tetrazolium-reductase, succinic dehydrogenase and phosphorylase and of the content of fat and glycogen in the muscles of the cat's lumbar back region. The correlation between the fiber composition and the previously studied contraction properties of the muscles was analyzed. All muscles contain fibers with a low activity (type I) and such with a high activity (type II) of myofibrillar ATPase following preincubation at pH 9.4. Type II fibers showed either a low (type II A) or an intermediate (type II B) reaction when stained for ATPase, preincubation at pH 4.6. Type I fibers have a high, II A an intermediate-high and II B fibers a low activity of oxidative enzymes. The longissimus, iliocostalis and sacrocaudalis dorsalis lateralis muscles are characterized by high percentages of type II B fibers and low proportions of type I and type II A fibers. The central region of the longissimus which is connected to a well developed intermuscular septum is composed of a high proportion of type I fibers. The multifidi, interspinales and intertransversarii mediales muscles have higher proportions of type I and type II A fibers than the other muscles in the region.
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PMID:Histochemical fiber composition of lumbar back muscles in the cat. 15 Jan 95

EUE cells from a human heteroploid line cultured in hypertonic medium (0.274 M NaCl) modify their lipid pattern: sulfolipid concentration reaches 86 to 90 microgram/mg protein whilst it ranges between 19 to 32 microgram/mg in cells cultured in isotonic medium. Ganglioside concentration reaches 2.6 nmoles of sialic acid/mg protein (after 75 days) and 13 (after 85 days) in hypertonic saline medium. Whilst it is 0.5 in isotonic medium. Phospholipid concentration does not show any similar change. Cytoenzymatic analysis reveals that dehydrogenases (lactate, G-6-P dehydrogenases, tetrahydrofolate reductase and NADH diaphorase) appear strongly enhanced in cells grown on hypertonic medium. On the contrary higher acid phosphatase and ATPase activity was demonstrable in cells grown on isotonic medium. These results are similar (except for ATPase activity) to those observed in salt secreting glands involved in strong osmotic work. The results are discussed in relation to the problem of energy supply in cells performing osmotic work.
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PMID:Biochemical and histochemical features of human cultured cells (EUE) adapted to hypertonic medium. 15 74

Sulfate-reducing bacteria, Desulfovibrio vulgaris, strain Miyazaki, were grown on either sulfate, sulfite, or thiosulfate as the terminal electron acceptor. Better growth was observed on sulfite and less growth on thiosulfate than on sulfate. Enzyme levels of adenylylsulfate (APS) reductase [EC 1.8.99.2], reductant-activated inorganic pyrophosphatase [EC 3.6.1.1], sulfite reductase [EC 1.8.99.1] (desulfoviridin), hydrogenase [EC 1.12.2.1], and Mg2+-activated ATPase [EC 3.6.1.3] were compared in crude extracts of these cells at various stages of growth. 1) The specific activity of APS reductase in sulfite-grown cells was only one-fourth that in sulfate-grown cells throughout growth. Thiosulfate-grown cells had an activity intermediate between those of sulfate- and sulfite-grown cells. 2) Cells grown on sulfite had lower specific activity of reductant-activated inorganic pyrophosphatase than cells grown on sulfate or thiosulfate. 3) The specific activity of sulfite reductase (desulfoviridin) was highest in sulfite-grown cells. The sulfite medium gave the enzyme in high yield as well as with high specific activity. 4) The specific activities of hydrogenase and Mg2+-ATPase were not significantly altered by electron acceptors in the growth medium.
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PMID:Biochemical studies on sulfate-reducing bacteria. XIV. Enzyme levels of adenylylsulfate reductase, inorganic pyrophosphatase, sulfite reductase, hydrogenase, and adenosine triphosphatase in cells grown on sulfate, sulfite, and thiosulfate. 17 50


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