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)

A method is described for preparation of membrane vesicles (diameter 80nm) capable of respiration-linked ATP synthesis. Vesicles prepared from succinate-grown bacteria oxidized NADH, succinate and ascorbate plus NNN'N'-tetramethylphenylenediamine; vesicles prepared from methanol-grown bacteria also oxidized methanol and formaldehyde, but they were otherwise identical. The uncoupling agent carbonyl cyanide chlorophenylhydrazone and the adenosine triphosphatase inhibitor dicyclohexylcarbodi-imide both inhibited ATP synthesis, whereas they had no effect on the rate of respiration. Rotenone inhibited ATP synthesis and respiration with NADH as substrate; antimycin A inhibited with succinate as substrate, and cyanide inhibited with all substrates. P/O ratios were usually 0.7-1.3 with NADH, 0.6-1.0 with succinate and 0.2-0.6 with reduced NNN'N'-tetramethylphenylenediamine or methanol as respiratory substrate. When 2,6-dichlorophenol-indophenol was used as an alternative electron acceptor to O(2) (NADH as donor) the P/2e ratio was 1.65. Although these P/O ratios are minimum values, because they do not take into account unknown amounts of uncoupled O(2) consumption, they are consistent with previous proposals [O'Keeffe & Anthony (1978) Biochem, J.170, 561-567] based on measurements of proton translocation in whole cells. The results also confirm that methanol dehydrogenase and cytochromes c and a/a(3) are arranged so that the first step in methanol oxidation is coupled to synthesis of ATP.
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PMID:The microbial metabolism of C1 compounds. Oxidative phosphorylation in membrane preparations of Pseudomonas AM1. 22 Sep 60

Mechanisms determining the natriuresis in ECV expansion are not yet completely known. The present study was therefore performed to investigate (1) the extent to which prostaglandins (PG) are involved in the natriuresis of ECV expansion and (2) by which mechanisms PG may affect renal Na absorption. In nonexpanded rats the prostaglandin synthetase inhibitor indomethacin (INDO) had no effect on renal function. In 16 Sprague-Dawley rats EVC expansion with isotonic saline corresponding to an increase in body weight of 10% was induced and maintained for 60 min. Ten animals received an oral dose of 10 mg/kg BW of INDO prior to ECV expansion. Six animals served as controls (C). Blood pressure (INDO: 132 +/- 4 (SE); C: 130 +/- 3 mm Hg), GFR (INDO: 12.5 +/- 1.0; C: 10.5 +/- 0.9 ml/min/kg BW), fractional K excretion (INDO: 32.1 +/- 2.6; C: 43.4 +/- 4.8%), CH2O and Na-k-ATPase activities in renal cortex, medulla and papilla did not significantly differ in either group. Significant differences were observed in urinary flow rate (INDO: 0.82 +/- 0.8; C: 1.82 +/- 0.23 ml/min/kg KG) and fractional Na absorption (INDO: 91.9 +/- 1.1; C: 81.7 +/- 1.2%). The results indicate that PG are involved in the natriuresis following acute expansion of the ECV and suggest that PG may inhibit the intrinsic tubular capacity for Na absorption in the rat.
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PMID:The role of prostaglandins in the natriuresis of acutely salt-loaded rats. 85 79

Parvalbumin (PV) is a soluble Ca++ binding protein which is particularly concentrated in fast muscles of rodents. We have developed a new protocol to fix frozen sections of muscle by formaldehyde vapor, which enabled us to immunochemically stain serial frozen sections for PV. Fiber types were defined on the basis of myosin ATPase stability, and of isomyosins identified by a variety of antibodies because ATPase stability alone yielded ambiguous results in the mouse. Slow Type I fibers in mouse and rat were devoid of PV and had intermediate to high SDH levels. Fast fiber subtypes IIA, IIB, and IIX-like were defined in the mouse on the basis of the similarity of their myosin heavy chain immunoreactivity to these types in the rat. The soleus muscle was usually PV negative, but a small population of strongly PV-positive IIX-like fibers was present in the mouse. In mouse fast muscle, small diameter IIA fibers were PV negative with high SDH activity. In both mouse and rat, PV reactivities of IIB and IIX fibers were higher than those of IIA and I, whereas SDH levels of IIA, IIX, and I fibers were higher than those of IIB. Thus, PV content correlated with the type of myosin ATPase but not with SDH levels. The method described for immunocytochemistry of PV may be applicable to other highly soluble proteins.
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PMID:Direct correlation of parvalbumin levels with myosin isoforms and succinate dehydrogenase activity on frozen sections of rodent muscle. 182 16

Formaldehyde (HCHO) has been reported to impair mucociliary clearance. The present investigation using rabbit and porcine tracheal explants in vitro examined (1) the impairment of ciliary activity, an essential component of mucociliary clearance; (2) the reversibility of ciliary dysfunction after HCHO exposure; and (3) the mechanism by which ciliary activity is reduced by HCHO. HCHO treatment of rabbit tracheal rings significantly decreased zones of active ciliated epithelium in direct proportion to concentration and exposure duration. There was also a significant concentration-dependent reduction of ciliary beat frequency. Removal of HCHO permitted recovery of zones of ciliary activity to normal beat frequencies; greater inhibitory concentrations of HCHO required greater time for return of function. Treatment of porcine tracheae with increasing concentrations of HCHO for time periods inhibitory to rabbit ciliary activity correspondingly reduced the yield of cilia extractable from treated epithelium. Furthermore, the specific activity of ATPase of extracted ciliary axonemes was diminished with increasing HCHO concentration, indicating loss of function. A recovery period following identical exposures of the porcine tracheae to the lower HCHO concentrations resulted in normal yields of functionally intact ciliary axonemes. Similarly, a recovery period after the highest HCHO concentration produced more functional axonemes than obtained from exposed tracheae without a recovery period, although less than normal yields. Therefore, ciliary dysfunction elicited by a defined range of HCHO concentrations is reversible. The yield and functional integrity of ciliary axonemes from epithelium exposed to HCHO with a recovery period are significantly greater than those without such a recovery period, suggesting an alteration and subsequent repair of epithelial surface components following HCHO exposure.
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PMID:Inhibition and recovery of mammalian respiratory ciliary function after formaldehyde exposure. 213 68

Activities of Ca2(+)-dependent ATPase, Mg2(+)-dependent ATPase, Na(+)-K(+)-dependent ATP-ase, alkaline phosphatase, and 5'-nucleotidase were demonstrated after incubation of 40-microns vibratome sections of bovine parathyroids and subsequent visualization by electron microscopy. Prior to sectioning, parathyroid tissue was fixed with 1% glutaraldehyde for localization of alkaline phosphatase, and with 2% formaldehyde and 1% glutaraldehyde for demonstration activities of ATPases and 5'-nucleotidase. The activities of the five enzymes were found at the apicolateral domain of the plasma membrane in parathyroid cells, i.e. at the site parathyroid cells face neighbouring parenchymal cells. Ca2(+)-ATPase activity was also seen on mitochondria, Golgi complex and RER. The presence of these plasma membrane associated enzymes at the apicolateral domain only indicate polarity in parathyroid cells. It further suggests that many processes including transmembrane transport take place at the apicolateral domain, the site of parathyroid cells opposing blood capillaries.
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PMID:Parathyroid cell polarity as revealed by cytochemical localization of ATPases, alkaline phosphatase and 5'-nucleotidase. 214 38

H(+)-K(+)-ATPase and carbonic anhydrase II (CA II) are two enzymes that are involved in the production and secretion of the hydrogen ion by the gastric parietal cell and maintenance of intracellular pH therein. The present studies were undertaken to examine whether H(+)-K(+)-ATPase and CA II expression change in the rat fundus in association with the development of acid secretory capacity. Changes in enzyme mRNA content in the gastric fundus of developing rat pups 1-6 wk of age were evaluated using dot blots and ribonuclease protection assays. In additional studies the localization of H(+)-K(+)-ATPase and carbonic anhydrase II mRNA was examined by in situ hybridization in Formalin-fixed gastric tissues from rats 1, 3, 6, and 8 wk of age. We observed that H(+)-K(+)-ATPase mRNA content increased with age in the developing rat fundus while CA II mRNA exhibited a reciprocal decrease. These changes in enzyme mRNA were accompanied by concomitant changes in the regional distribution of the cells expressing the genes for the two enzymes. Although the changes in H(+)-K(+)-ATPase mRNA paralleled the development of acid secretory capacity, CA II mRNA levels might be regulated by the requirement for maintenance of intracellular pH during periods of cellular proliferation and by exposure of the gastric surface epithelium to the highly acidic luminal environment of the stomach.
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PMID:H(+)-K(+)-ATPase and carbonic anhydrase II gene expression in the developing rat fundus. 216 89

Spectrophotometric and cytochemical methods were used to investigate the localization and/or the sensitivity of phosphatase activities in aldehyde-fixed beet leaves and membrane fractions. The nonspecific acid phosphatase substrates, p-nitrophenyl phosphate and beta-glycerol phosphate, each exhibited unique spectrophotometric patterns of hydrolysis as a function of pH. Additionally, beta-glycerol phosphatase activity was primarily present on the tonoplast, whereas p-nitrophenyl phosphatase was present on the plasma membrane. Because of the unique pH response of each enzyme and their different localization, we conclude that they cannot be entirely "nonspecific." The spectrophotometric pattern of ATP hydrolysis differed from that of p-nitrophenol phosphate in that it decreased at pH 5.0-5.5 and was greatly inhibited by 10 mM sodium fluoride; however, both activities were on the plasma membrane. Therefore, we conclude that these activities represent either two enzymes or only one enzyme that differs in its ability to hydrolyze these two substrates. Generally, enzymatically produced lead deposits on the plasma membrane of non-vascular cells were as frequent and large as those on phloem cells; frequently, deposits on sieve element plasma membranes were relatively small. We therefore conclude that there is no evidence for the presence of relatively intense ATPase activity on the plasma membrane of phloem cells in beet leaf, in contrast to other species. Studies with membrane fractions indicated that formaldehyde could completely inhibit the inhibitor-sensitive phosphatase activities in mitochondrial and vacuolar fractions while preserving significant activity in the plasma membrane fraction.
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PMID:Spectrophotometric and cytochemical analyses of phosphatase activity in Beta vulgaris L. 241 91

The effects of the condensation product of N-methyl-p-methoxyphenethylamine with formaldehyde (compound 48/80) and ruthenium red on the partial reactions of the catalytic cycle of the sarcoplasmic reticulum Ca2+-ATPase of skeletal muscle were studied. The ATPase activity and both Ca2+ and Sr2+ uptake were inhibited by compound 48/80 when oxalate was used as a precipitating agent. The degree of inhibition decreased when oxalate was replaced by orthophosphate as the precipitating anion. Both the fast Ca2+ efflux and the synthesis of ATP observed during reversal of the Ca2+ pump were inhibited by compound 48/80. Inhibition of the reversal of the Ca2+ pump was caused by a competition between compound 48/80 and orthophosphate for the phosphorylation site of the enzyme. The fast Ca2+ release promoted by arsenate was impaired by compound 48/80. Ruthenium red competes with Ca2+ for the high affinity binding site of the Ca2+-ATPase, but did not interfere with the binding of Ca2+ to the low affinity binding site of the enzyme. In presence of Ca2+ concentrations higher than 5 microM, ruthenium red in concentrations up to 200 microM had no effect on both ATPase activity and Ca2+ uptake. However, the fast Ca2+ efflux promoted by arsenate and the fast Ca2+ efflux coupled with the synthesis of ATP observed during the reversal of the Ca2+ pump were inhibited by ruthenium red, half-maximal inhibition being attained in presence of 10-20 microM ruthenium red. In contrast to the effect of compound 48/80, ruthenium red did not inhibit the phosphorylation of the enzyme by orthophosphate. The ATP in equilibrium with Pi exchange catalyzed by the Ca2+-ATPase in the absence of transmembrane Ca2+ gradient was also inhibited by ruthenium red.
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PMID:Effect of compound 48/80 and ruthenium red on the Ca2+-ATPase of sarcoplasmic reticulum. 243 Sep 71

To study the topology of Na+,K+-ATPase monoclonal antibodies (MAbs) specific for membrane-bound enzyme were produced. Using immunofluorescence staining of viable cells or smears of a pig kidney embryonic (PKE) cell line, two groups of MAbs were selected, namely those binding to extra- or intracellular portions of the alpha-subunit. The extracellular location of peptide loop 804-841 linking the Vth and VIth intramembrane hydrophobic segments was proved using MAb VG2. Another MAb, IIC9, interacting with PKE cells only after membrane perforation (4% formaldehyde and 0.1% Tween-20), was shown to bind to the hydrophilic loop 868-945. The antigenic determinants recognized by MAb IIC9 and VG2 are located in peptides 887-904 and 810-825, respectively. The C-terminus of the alpha-subunit molecule was positioned on the outer side of the cytoplasmic membrane utilizing affinity-purified antibodies to the synthetic peptide corresponding to fragment 999-1008.
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PMID:Topology of Na+,K+-ATPase. Identification of the extra- and intracellular hydrophilic loops of the catalytic subunit by specific antibodies. 244 69

We describe a technique for analysis by light microscopic immunocytochemistry of the distribution of plasmalemmal proteins in polarized epithelial cells. For this purpose, Madin Darby Canine Kidney (MDCK) cells were grown to confluency on Cytodex beads, the beads were fixed with formaldehyde, and semi-thin (0.5 micron) sections were cut at liquid nitrogen temperature on an ultracryomicrotome. The distribution of the basolaterally distributed plasmalemmal protein, Na,K-ATPase, was assessed by indirect immunofluorescence using a monospecific polyclonal antibody directed against the alpha-subunit of the Na pump. Such preparations enable epithelial monolayers to be evaluated in cross-section, thus permitting unambiguous topological assessment of apical and basolateral membrane proteins. Thus, the spatial uncertainties encountered in en face examination of membrane protein distribution in epithelia grown on solid supports are largely obviated. In addition, we describe a technique for removal of the bead matrix, which markedly reduces nonspecific background staining and improves access of reagents to the basal cell surface, thus permitting localization of basal lamina components.
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PMID:Immunocytochemical localization of plasmalemmal proteins in semi-thin sections of epithelial monolayers. 244 92


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