Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.6.1.3 (ATPase)
65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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

Frozen sections of equine musculus semitendinosus were examined for myosin adenosine triphosphatase (ATPase) and reduced nicotinamide adenine dinucleotide-tetrazolium reductase (NADH-TR), using standard histochemical procedures, and the proportions of the various fiber types and average fiber sectional size were determined. With ATPase staining, approximately 70% of the fibers were classified as alpha fibers (ATPase positive), and 30%, as beta fibers (ATPase negative). In addition, 2 populations of alpha fibers could be readily distinguished on the basis of the intensity of the ATPase reaction, and these were designated alpha positive and alpha intermediate. The relationship of this difference in ATPase reaction to contraction speed of the fibers is not known. With NADH-TR staining, fibers were classified as either red fibers (positive) having aerobic metabolism or white fibers (negative) having primarily anaerobic metabolism. All beta fibers were red by NADH-TR; thus, they conformed to the criteria for beta R fibers. All alpha positive fibers were white by NADH-TR, as were most of the alpha intermediate fibers, and would be classified alpha W. Some of the alpha intermediate fibers gave an intermediate reaction with NADH-TR and could be classified as alpha R fibers which have not transformed to alpha W fibers. The alpha positive fibers were 7 to 10 mum larger in diameter than either beta or alpha intermediate fibers.
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PMID:Fiber types and size in equine skeletal muscle. 13 Aug 14

Measurement of certain membrane-bound enzymic activities was used to study the orientation of the outer membrane of the double-membraned forespore of Bacillus megaterium KM. 2. Adenosine triphosphatase, NADH dehydrogenase and L-malate intact protoplasts, but were readily detected in intact stage II or IV forespores, consistent with reversed polarity of the outer forespore membrane relative to the mother-cell plasma membrane. 3. Measurement of NADH oxidase activity revealed that intact stage III forespores had the same high affinity for NADH as protoplast membrane preparations and protoplast lystates, consistent with ready access of NADH to oxidation sites on the outer forespores membrane. 4. Forespores and protoplasts showed osmometric behaviour in solutions of non-permanent solutes consistent with the presence of an intact permeability barrier in these structures.
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PMID:Biochemical evidence for the reversed polarity of the outer membrane of the bacterial forespore. 13 69

Membrane vesicles were prepared by osmotic lysis of spheroplasts from M13-infected Escherichia coli. Reduced nicotinamide adenine dinucleotide (NADH) oxidase (reduced NAD: oxidoreductase, EC 1.6.99.3) and Mg2+-Ca2+-activated adenosine triphosphatase (ATP phosphohydrolase, EC 3.6.1.3), which are normally localized to the inner surface of the cytoplasmic membrane, were 50% acceesible to their polar substrates in these vesicles. The major coat protein of coliphage M13 is also bound to the cytoplasmic membrane (prior to phage assembly) but with its antigenic sites exposed to the exterior of the cell. Antibody to M13 coat protein was used to fractionate membrane vesicles. Neither agglutinated nor unagglutinated vesicles had altered NADH oxidase and adenosine triphosphatase specific activities. This is inconsistent with such vesicles being a mixture of correctly oriented and completely inverted membrane sacs and suggests that NADH oxidase, adenosine triphosphatase, M13 coat protein, or all three proteins rearrange during vesicle preparation.
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PMID:Fractionation of membrane vesicles from coliphage M13-infected Escherichia coli. 13 27

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

Four cytoplasmic mutants of Saccharomyces cerevisiae showing loss of mitochondrial rutamycin-sensitive ATPase activity but having significant cytochrome oxidase and NADH-cytochrome c reductase have been isolated. Genetic studies indicate the mutations to be closely linked to each other and have been assigned to a new locus, PHO1. The mutations show a low frequency of recombination with the OL12 locus, suggesting a linkage to this marker. They are not, however, linked to the OLI1 locus. Linkage of the ATPase mutations to the OLI2 locus is also indicated by restoration of wild-type diploids by sigma- clones that retain the segment of mitochondrial DNA carrying OLI2. Based on the recombinants issued from crosses of the mutants with a triple drug-resistant strain and an analysis of the resistance markers present in sigma- clones that are effective in restoring a wild-type phenotype, the PHO1 locus has been placed in the segment of DNA located between PAR1 and OLI2.
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PMID:Localization on mitochondrial DNA of mutations leading to a loss of rutamycin-sensitive adenosine triphosphatase. 13 92

Phosphorylating submitochondrial particles from beef heart (ETPH) prepared here contained about 2.4 nmol of ATP and 1.9 nmol of ADP/mg of protein after repeated washing of the particles. Essentially all of the "tightly bound " ATP and ADP was removed by trypsin treatment. The trypsin-treated ETPH had increased ATPase activity, undiminished NADH oxidase and succinate oxidase activity, but energy-coupling activity (ATP-driven reversed electron transfer) was abolished. Removal of half the ATP and ADP occurred at low levels of trypsin and was associated with loss of half of the coupling activity. Gel filtration of ETPH in high ionic strength buffer also removed ADP and ATP from the particles, resulting in loss of energy-coupling activity, while ATPase activity was increased. The results support the contention that the tightly bound ADP is essential in energy coupling in mitochondria. Tightly bound ATP may also play an essential role.
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PMID:Removal of "tightly bound" nucleotides from phosphorylating submitochondrial particles. 13 46

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

The mechanism of action of some quinoline alkaloids and their derivatives on respiratory chain of rat liver and Candida lipolytica yeast mitochondria was studied. The alkaloids were shown to inhibit electron transfer in the respiratory chain. The site of their action is localized between b and c cytochromes. Besides their ability to inhibit electron transfer in the respiratory chain, alkaloids are shown to be specific inhibitors of "exogenous" NADH-dehydrogenase of C. lipolytica yeast mitochondria. In addition to their inhibiting properties alkaloids can stimulate ATPase activity of mitochondria. O-alkylation of pseudane-IX permits to differentiate the inhibiting and uncoupling properties of this alkaloid.
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PMID:[Mechanism of action of some quinoline alkaloids on respiratory chain of mitochondria]. 13 72

The masseter muscles of different mammals were studied by means of hisotchemical reactions: NADH: Nitro BT oxidoreductase (NADHOX), 3-hydroxybutyrate: NAD+ oxidoreductase (HBOX), glycerol-3-phosphate: menadione oxidoreductase (GPOX), and acid-stable and alkali-stable myosin adenosine triphosphatase (ATPase). The masseter mucles of cattle and sheep consisted only of the fibres that reacted moderately for GPOX and strongly for NADHOX, HBOX, and the acid-stable ATPase. The masseter fibres of rats and guinea pigs reacted uniformly and strongly for GPOX and the alkali-stable ATPase. The fibres of the rats showed a weak to strong reaction for NADHOX and mostly a negative reaction for HBOX, whereas those of the guinea pigs reacted uniformly and strongly for NADHOX and HBOX.The masseter fibres of swine and dogs showed a weak or strong reaction for the alkali-stable and a negative or weak reation for HBOX. The fibres of the swine were weak to strong in NADHOX activity and those of the dogs uniformly strong; the fibres of the two species gave a moderate to strong reaction for GPOX. The masseter fibres of the ruminant differed from those of the other species in histochemical properties, and appeared to have the histochemical characteristics that meed functional demands for slow, long-term exercise.
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PMID:A comparative histochemical study of the masseter muscle of the cattle, sheep, swine, dog, guinea pig, and rat. 13 87


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