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)

The rate coefficient for (22)Na release from previously labeled human erythrocytes was determined in the presence of 0.1-10 mM sodium fluoride (F). The oxidized nicotinamide adenine dinucleotide (NAD(+)) level at the end of 2 hr of incubation in tris(hydroxymethyl)aminomethane (Tris)-Ringer medium was also measured. Both parameters decreased proportionately as F concentration was raised. Both F-induced changes were immediate and were reversed by 10 mM pyruvate. The decrease in NAD(+) concentration following enolase inhibition by F is attributed to a diminished rate of formation in the reaction catalyzed by lactic dehydrogenase (LDH) with undiminished continued utilization in the reaction catalyzed by glyceraldehyde-3-phosphate dehydrogenase (GAPDH). It is postulated that the NAD(+) lowering limited the GAPDH step, resulting in proportionate decreases in the rates of phosphoglycerate kinase (PGK) and Na,K-dependent adenosine triphosphatase (Na,K-ATPase), a reaction sequence thought to link glycolysis with active Na extrusion. Adding pyruvate with F increased NAD(+) production at the LDH step, thus reactivating GAPDH, PGK, and Na,K-ATPase and leading to the observed restoration of (22)Na release. The results suggest, therefore, that F inhibits active Na transport in intact human erythrocytes indirectly through a lowering of NAD(+), although, direct inhibition of the Na,K-ATPase by F may possibly occur simultaneously.
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PMID:The role of oxidized nicotinamide adenine dinucleotide in fluoride inhibition of active sodium transport in human erythrocytes. 434 51

The ATPase activity of rabbit isolated renal tubule segments was measured using a microtechnique in which the hydrolysis of ATP was enzymatically coupled to the appearance of an alkali-converted, highly fluorescent form of nicotinamide adenine dinucleotide. The methods are simple, reproducible, and have a high sensitivity in which picomole quantities of hydrolyzed ATP can readily be measured. Several methods for permeabilizing the cell membranes for measurement of Na+-K+-ATPase activity were evaluated, including osmotic (distilled water or 300 mM imidazole) and temperature (freezing) shock and addition of the nonionic detergent octylglucoside. An octylglucoside concentration of 0.5% was found to cause a maximum activation of the Na+-K+-ATPase and was comparable with that observed when tubules were permeabilized by exposure to distilled water and freezing. Incubation of tubules in 300 mM imidazole was less effective in permeabilizing the cell membranes. In all subsequent studies, the cells were permeabilized by exposure to distilled water and freezing as done by others. The methods were used to assay for the basal levels of Na+-K+-ATPase in the superficial proximal convoluted tubule, the superficial proximal straight tubule, and the cortical collecting tubule and were found to average 44.9 +/- 6.3, 26.4 +/- 2.4, and 11.8 +/- 2.2 pmol ADP X mm-1 X min-1, respectively. Furthermore, elevation of plasma mineralocorticoids by daily injections of deoxycorticosterone acetate (2 mg X kg-1 X day-1) for 4-15 days caused a doubling in the Na+-K+-ATPase activity of the cortical collecting duct, confirming the results of others. The methods presented can easily be adapted for microanalysis of other ATPases.
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PMID:Micromethodology for measuring ATPase activity in renal tubules: mineralocorticoid influence. 609 64

A total of 147 muscle spindles was studied histochemically in serial transverse sections of 42 cat tenuissimus muscle specimens. Nuclear bag1, nuclear bag2 and nuclear chain intrafusal muscle fibers were distinguished by the differential staining resulting from the reactions for myosin adenosine 5'-triphosphatase and nicotinamide adenine dinucleotide tetrazolium reductase. The majority of intrafusal fibers were of the same histochemical type at both fiber poles. However, seven muscle spindles contained one nuclear bag fiber each that presented as a bag1 in one pole and as a bag2 in the other pole. These "mixed" nuclear bag fibers were found in spindles that also contained at least one bag1 and one bag2 fiber of equivalent histochemical presentation in both fiber poles. The "mixed" bag fibers displayed differences of apparent fiber diameter and relative polar length between the two fiber poles. The motor innervation pattern, as revealed by staining for cholinesterase, was also dissimilar between the two poles of "mixed" bag fibers. The study indicates that the spindle equatorial region may in some instances serve as a boundary between two morphologically and histochemically different poles of the same intrafusal fiber.
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PMID:The occurrence of "mixed" nuclear bag intrafusal fibers in the cat muscle spindle. 616 92

Various physiological important activities of Mycoplasma gallisepticum were inhibited by the copper(I) complex of 2,9-dimethyl-1,10-phenanthroline [Cu(DMP)2NO3]. The energy-yielding metabolism was inhibited because the conversion of pyruvate into lactate was found to be blocked by Cu(DMP)2NO3, indicating a selective inhibition of lactate dehydrogenase. Also, the production rate of acetate and the rate of oxygen uptake by whole cells of M. gallisepticum appeared to be strongly decreased. Experiments with crude cell extracts showed an inhibition of reduced nicotinamide adenine dinucleotide (NADH) oxidase by Cu(DMP)2NO3 and an even stronger inhibition of NADH oxidase and lactate dehydrogenase by CuSO4. No preferential inhibition of adenosine 5'-triphosphatase and pyruvate kinase was found. Investigations on the influence of Cu(DMP)2NO3 on deoxyribonucleic acid, ribonucleic acid, and protein synthesis with growing cells of M. gallisepticum showed a selective inhibition of the incorporation of [14C]thymidine into deoxyribonucleic acid. Cu(DMP)2NO3 induced a decrease in the total amount of accessible sulfhydryl groups of whole cells of M. gallisepticum, indicating that the observed diverse toxicity of Cu(DMP)2NO3 may be associated with the interaction of copper ions with protein sulfhydryl groups.
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PMID:Mode of action of the copper(I) complex of 2,9-dimethyl-1,10-phenanthroline on Mycoplasma gallisepticum. 617 82

A fixative solution that preserves the activity of some relevant enzymes in muscle histochemistry is described. Portions of human muscle biopsy specimens and selected murine muscles were fresh frozen or placed in the fixative at room temperature for up to 1 month before freezing. Cryostat sections of fresh frozen and fixed frozen tissue were assayed for nicotinamide adenine dinucleotide phosphate (NADH)-tetrazolium reductase (NADH), several adenosine triphosphatases (ATPases), myoadenylate deaminase (MD), and phosphorylase. NADH, ATPase, and MD activity were preserved following fixation but phosphorylase was not preserved. Murine spleen and kidney were similarly tested for acid phosphatase (acid phos), alkaline phosphatase (alk phos), and nonspecific esterase (NSE). Alk phos activity was preserved but acid phos and NSE activity were significantly reduced following fixation. This fixative is useful in some circumstances for processing or shipping human muscle biopsy specimens and experimental tissues.
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PMID:A fixative for use in muscle histochemistry. 618 97

The striated muscle component of the opossum oesophagus has been studied for fibre type as revealed by histochemical stains for succinic acid dehydrogenase, adenosine triphosphatase, nicotinamide adenine dinucleotide dehydrogenase and after staining with the periodic acid-Schiff reagent. The reactions were compared to those obtained in a single human oesophagus. In both species, the striated muscle consisted of Type II fibres throughout, but at the pharyngeal end, some Type I fibres passed into the muscularis externa from the lower pharyngeal constrictor and extended for a short distance along the oesophagus. Differences in the reactions to these histochemical stains indicated that the Type II fibres of the opossum oesophageal musculature are subtype A, while those of the human are subtype B.
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PMID:Histochemistry of the striated musculature in the opossum and human oesophagus. 621 Jun 50

We determined muscle fiber type and capillarity in cremaster muscle samples from rats and hamsters of different ages. Histochemical estimation of oxidative capacity was made from the activity of either nicotinamide dinucleotide tetrazolium reductase (NADH-TR) or succinic dehydrogenase (SDH), and fibers were termed fast or slow from myofibrillar ATPase activity. Fibers were classified as type I (low ATPase, high NADH-TR/SDH), type IIa (high ATPase, high SDH/NADH-TR), type IIb (high ATPase, low SDH/NADH-TR), or type IIc (no acid reversal of ATPase, high NADH-TR). Type IIb fibers accounted for 60-80% of the muscle area in both species at all ages. The principal change with maturation was muscle fiber hypertrophy. Mean cross-sectional fiber area increased from 488 +/- 70 (SE) and 453 +/- 19 micron2 in young hamsters and rats, respectively, to 1,255 +/- 99 and 1,540 +/- 101 micron2 in adults. Capillary density (no. of capillaries/mm2 tissue) paralleled fiber hypertrophy; it decreased significantly with maturation from 684 +/- 60 (SE) to 228 +/- 26/mm2 in hamsters and from 341 +/- 15 to 213 +/- 15/mm2 in rats. In vitro estimates of capillary density are compared with previously obtained in vivo data (31), and sources of error are identified. We conclude that reported differences in microvascular function in the cremaster muscle in vivo during maturation or between species cannot be ascribed to changes in muscle composition.
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PMID:Capillarity and fiber types in the cremaster muscle of rat and hamster. 622 29

A gentamicin-resistant mutant of Pseudomonas aeruginosa PAO503 was selected after ethyl methane sulfonate mutagenesis. The strain, P. aeruginosa PAO2401 had increased resistance to all aminoglycosides tested but exhibited no change for other antibiotics. The mutation designated aglA (aminoglycoside resistance) was 50% cotransducible with the 8-min ilvB,C marker on the P. aeruginosa chromosome. It showed a marked reduction in cytochrome c(552) and nitrate reductase (Nar) and a change in terminal oxidase activity. Cytochrome c(552) is a component of the P. aeruginosa Nar. No changes in succinate and reduced nicotinamide adenine dinucleotide dehydrogenases, ubiquinone content, Mg(2+)/Ca(2+) membrane adenosine triphosphatase, and energy coupling of electron transport to adenosine 5'-triphosphate synthesis were detected. Transport of gentamicin and dihydrostreptomycin was impaired in PAO2401, but transport of proline, arginine, glutamine, glucose or the polyamine spermidine was not reduced. Ribosomes of PAO2401, and PAO503 bound dihydrostreptomycin equally well, and cell extracts did not inactivate gentamicin or dihydrostreptomycin. Strain PAO2401 is resistant to gentamicin and dihydrostreptomycin because of impaired transport of these compounds. The transport studies indicate a selective coupling of dihydrostreptomycin and gentamicin transport with terminal electron transport. This conclusion was supported by results from another mutant (PAO417-T2) with increased Nar activity, enhanced dihydrostreptomycin and gentamicin transport and a reduction in resistance to these drugs. These results are discussed in relation to a refined model for aminoglycoside transport and briefly relative to plasmid-mediated aminoglycoside resistance.
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PMID:Aminoglycoside-resistant mutation of Pseudomonas aeruginosa defective in cytochrome c552 and nitrate reductase. 624 53

We report the results of studies in which the cytoplasmic coupling between Na+,K+-ATPase activity (presumably a measure of active transport) and the mitochondrial respiratory rate was investigated in a tubule suspension from the rabbit kidney cortex. Simultaneous measurements of the redox state of mitochondrial nicotinamide adenine dinucleotide (NAD) (performed fluorometrically), the cellular ATP and ADP concentrations, and the oxygen consumption rate (QO2) were made under conditions known to alter the Na+,K+-ATPase turnover. Ouabain (25 microM) caused: (i) a 54% inhibition of QO2, (ii) a net reduction of NAD, and (iii) a 30% increase in the ATP/ADP ratio. The addition of K+ (5 ?M) to K+-depleted tubules caused: (i) an initial 127% stimulation of QO2 followed by a new steady-state QO2 50% above control, (ii) an initial large oxidation of NAD followed by a new steady state more oxidized than the control level, and (iii) a 47% decrease in the cellular ATP/ADP ratio. These data indicate that the cellular ATP and ADP concentrations or the ATP/ADP ratio may be part of the coupling mechanism linking Na+,K+-ATPase turnover and the aerobic metabolic rate in kidney.
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PMID:Coupling of active ion transport and aerobic respiratory rate in isolated renal tubules. 624 59

Oxygen (O2) consumption and net K+ uptake were measured simultaneously upon reintroduction of K+ into a K+-depleted suspension of renal tubules. The K+/O2 stoichiometries of 11.8 +/- 0.2 and 8.4 +/- 0.6 were obtained for reduced nicotinamide adenine dinucleotide- and flavoprotein-linked substrates, respectively. These values complement classical K+ to adenosine triphosphate (ATP) and ATP/O2 stoichiometries, thereby demonstrating a remarkably efficient coupling between the processes of Na+- and K+-dependent adenosinetriphosphatase-mediated ion transport and oxidative phosphorylation within the intact cell.
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PMID:Oxygen consumption and cellular ion transport: evidence for adenosine triphosphate to O2 ratio near 6 in intact cell. 624 81


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