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 (Na+ + K+)-ATPase is localized to the cerebral endothelium, i.e. the blood-brain barrier, and is important for the maintenance of the brain electrolyte environment. Data from the present study indicate that Pb2+ inhibits the binding of [3H]ouabain to the cerebral microvascular (Na+ + K+)-ATPase in a time- and dose-dependent manner. Pb2(+)-induced inhibition developed slowly with a maximum obtained after 40 min. Inhibition of [3H]ouabain binding to the enzyme was 48% at 10 microM Pb2+ and appeared maximal (89%) at 100 microM Pb2+ when compared to [3H]ouabain binding in untreated microvessels at 40 min. In contrast, 100 microM Al3+ caused a 55% increase in [3H]ouabain binding to the (Na+ + K+)-ATPase, relative to untreated microvessels at 40 min. Insulin or bovine serum albumin stimulated [3H]ouabain binding to the enzyme when added at similar concentrations. However, the addition of both insulin and bovine serum albumin did not result in an additive effect. These results show that insulin exerts a nonspecific effect on [3H]ouabain binding to the (Na+ + K+)-ATPase similar to that evoked by bovine serum albumin. However, the metal ions Pb2+ and Al3+ provoke selective alterations in the cerebromicrovascular (Na+ + K+)-ATPase with Pb2+ inhibiting and Al3+ stimulating [3H]ouabain binding.
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PMID:Control of [3H]ouabain binding to cerebromicrovascular (Na+ + K+)-ATPase by metal ions and proteins. 216 70

The investigation involved 4 mastitis-free cows, exposed to 168 h of suspended milking to induce prolonged milk stasis and premature mammary regression during mid-lactation. After 48 h the milk stasis elicited mastitis-like changes in the clinical, somatic cell count (SCC), bovine serum albumin (BSA) and beta-N-acetyl-D-glucosaminidase (NAG) characteristics of the udder secretions. Such changes in secretions from non-mastitic regressive mammary glands raise doubts about the present knowledge, definition, and diagnosis of so-called non-specific or aseptic mastitis. Determinations of fluctuating lacteal concentrations of lactose, galactose, mannose and glucose suggest that the secretory epithelium altered its metabolism and integrity in response to the intramammary perturbation by following a certain pattern of regressive adjustments which: (i) were apparently triggered during the initial 24 h of perturbation by disturbed Na-K-ATPase activities, followed by a cascade of changes in ion regulation, carbohydrate metabolism and increased formation of lactic acid as a metabolic end-product; (ii) advanced in a stepwise fashion during 0-24, 24-72 and 72-168 h of perturbation from recognition response to alarm reactions and manifestation of regression respectively; (iii) showed that markedly decreased carbohydrate levels preceded major increases of the SCC, BSA and NAG values; (iv) indicated that after 72 h of milk stasis leucocytic infiltrations sharply increased the SCC to more than 500,000 per ml and accelerated the manifestation of regression. The results of this study imply that extensive premature regression of healthy, and especially, pre-irritated udders could have significant implications for the development of different types of bovine mastitis during lactation and should be further investigated.
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PMID:Udder health implications of premature bovine mammary regression. I. Clinical, subclinical and reducing-sugar changes in milk during 168 hours of suspended milking in mid-lactation. 233 96

Albumin-free testis mitochondrial ATPase activity failed to be stimulated by either 2,4-dinitrophenol (DNP) or carbonyl cyanide rho-trifluoromethoxyphenylhydrazone (FCCP). DNP scarcely enhanced the state 4 respiration and mitochondria proved to be poorly coupled. When 1% bovine serum albumin was added to the isolation medium, DNP or FCCP stimulated ATPase nearly twofold and the dose-response curves for the uncouplers on the QO2 reached a plateau at five- to sixfold. The DNP coupling index (q) also showed a 30-40% improvement. A dose-response curve for oligomycin on the rate of [gamma-32P]ATP synthesis showed a stimulation of ATP synthase activity by 10-100 ng inhibitor/mg protein, suggesting a possible blockade of "open" F0 channels. In the albumin preparation oligomycin inhibited ATP synthesis in the range 10-100 ng/mg protein. Since testis ATPase is known to be loosely bound to the membrane, an effect of albumin, improving tightness in the interaction of the F1 and the F0 sectors of the ATPase, is suggested.
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PMID:The insensitivity to uncouplers of testis mitochondrial ATPase. 244 29

The voltage-sensitive sodium channel is an intrinsic membrane protein that is nonrandomly distributed in neurons, suggesting a possible interaction with other cellular constituents. In this study, we have directly tested the hypothesis that components of the cytoskeleton interact with sodium channels. Utilizing the methods of sodium dodecyl sulfate-polyacrylamide gel electrophoresis and blot overlay, we have identified a 33-kilodalton cytoskeletal protein (p33) that binds 32P-labeled sodium channel purified from rat brain. This binding is a high-affinity (KD less than 1 nM) protein-protein interaction that is blocked by low concentrations of unlabeled sodium channels but is not blocked by monosaccharides, the complex glycoprotein fetuin, the transmembrane protein Na+-K+-ATPase, or bovine serum albumin. Levels of p33 are highest in lung and spleen while lower levels are found in brain, peripheral nerve, skeletal muscle, liver, and testes. This tissue distribution implies that the sodium channel may not be the only ligand for p33.
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PMID:Identification of a 33-kilodalton cytoskeletal protein with high affinity for the sodium channel. 245 30

Diverse studies of three cytoplasmic proteins of Escherichia coli--SecB, trigger factor and GroEL--have suggested that they can maintain precursor proteins in a conformation which is competent for membrane translocation. These proteins have been termed 'chaperones'. Using purified chaperone proteins and precursor protein substrates, we find that each of these chaperones can stabilize proOmpA for translocation and for the translocation-ATPase. These chaperones bind to proOmpA to form isolable complexes. SecB and GroEL will also form complexes with another exported protein, prePhoE. In contrast, these chaperones do not form stable complexes with a variety of soluble proteins such as SecA protein, bovine serum albumin, ovalbumin or ribonuclease A. While chaperones may transiently interact with soluble proteins to catalyze their folding, the stable interaction between chaperones and presecretory proteins, maintaining an open conformation which is essential for translocation, may commit these proteins to the secretion pathway.
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PMID:Three pure chaperone proteins of Escherichia coli--SecB, trigger factor and GroEL--form soluble complexes with precursor proteins in vitro. 253 Oct 87

Canine renal Na,K-ATPase was treated with ATP dialdehyde, "oxATP" (20 microM), as described by G. Ponzio, B. Rossi, and M. Lazdunski (1983, J. Biol. Chem. 258, 8201-8205). In this system, a by-product, formaldehyde, was the inactivator. We modified the system to minimize such inhibition and to speed up the reaction. oxATP itself inactivated the enzyme at a rate that was slow at first and later speeded up. We fitted a precursor-product model to the data. Labeling with [3H]oxATP indicated about three sites per alpha beta protomer at complete inactivation. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the labeled enzyme showed radioactivity in many components, in the alpha and beta subunits and in small molecules at the tracker dye region. ATP (20 mM) prevented all labeling and inactivation. Ponzio et al. concluded that oxATP labels covalently an ATP binding site. Our experiments did not support this conclusion. Ouabain did not affect labeling. Sodium stimulated both inhibition and labeling more than potassium did, indicating a high-affinity ATP binding site, if any. But nucleotide specificity for preventing or producing inhibition did not correspond to nucleotide specificity for binding of ATP to the native enzyme. Blocking the ATP binding center with fluorescein isothiocyanate or fluorosulfonyl benzoyl adenosine had no effect on [3H]oxATP labeling. ATP also prevented [3H]oxATP labeling of bovine serum albumin or of integral-membrane proteins.
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PMID:Inhibition and labeling of sodium, potassium ATPase by the dialdehyde derivative of ATP. 253 59

A decrease in total activity of ATPase and in specific activity of Na+,K+-ATPase as well as less rapid and distinct decrease in specific activity of acetylcholinesterase were observed in synaptosomal membrane after binding of bilirubin in vitro. Irradiation with blue light of the bilirubin-containing membrane particles caused a more distinct decrease in activity of these enzymes. Blood serum albumin, added to the suspension of bilirubin-containing particles of synaptosomal membrane, affected significantly the alterations in activity of membrane-bound enzymes caused by the irradiation. Character of the effect depended on pH of the medium and presence of organophilic ligands in blood serum albumin molecule.
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PMID:[Functional changes in the synaptic membrane during in vitro interaction with bilirubin and serum albumin]. 256 Aug 69

The present paper is concerned with Na-K-ATPase. In the first part it deals with the effect of such factors as Na+, K+, Mg2+, ATP, pH on activity investigated using a soluble Na-K-ATPase from porcine cerebral cortex. In the second part a method for assaying red blood cell Na-K-ATPase is described. This method consists of specific steps for washing and preparation of red cell membranes, pretreatment of Na-K-ATPase with sodium dodecyl sulfate (SDS) and bovine serum albumin (BSA) and determination of enzymatic released inorganic phosphate. Na-K-ATPase prepared and treated in this way shows a higher activity than the conventionally prepared form of enzyme, as latent enzyme sites are exposed by the SDS treatment. The kinetic behaviour of Na-K-ATPase prepared and assayed by using this method is characterized and compared with that of soluble Na-K-ATPase.
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PMID:Studies on the determination of Na-K-ATPase in red blood cell membranes. 256 99

In this paper, progress towards the goal of understanding communication between the nucleus and cytoplasm using an in vitro system is reviewed. To probe the mechanism of nuclear targeting, we developed an in vitro transport system and have begun to dissect the highly selective process of nuclear transport. The basic parameters of transport were defined using an easily isolated nuclear protein, nucleoplasmin. To study the interaction of nuclear targeting signals with the pore, an artificial nuclear transport substrate was constructed, which consists of human serum albumin coupled to the signal sequence of the SV40 T-antigen. A similar peptide-protein conjugate was made using a mutant signal sequence. These conjugates were fluorescently labeled and/or tagged with gold and tested for transport in the in vitro system. High levels of nuclear transport of the wild-type signal sequence-containing protein were observed, while no transport of the mutant signal sequence-containing protein was seen. Thus, the in vitro system correctly recognizes the single amino acid change between the wild-type and mutant signal sequences. We found that the observed nuclear transport was completely dependent on the presence of ATP. Using the in vitro system we identified a specific inhibitor of nuclear transport, the lectin wheat germ agglutinin (WGA), which we find binds directly to the nuclear pore. Probing blots of nuclear proteins with 125I-WGA identified a family of nuclear pore glycoproteins, including one major glycoprotein of 62K (K = 10(3)Mr) molecular weight. With the inhibitor and the in vitro assay, it has been possible to experimentally separate nuclear transport into two steps: (1) a step in which the signal sequence-bearing protein binds to the pore, followed by (2) a step in which the protein translocates through the pore. It is this second step which is the ATP-dependent step of transport, since pore binding but not translocation was seen to occur in the absence of ATP.
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PMID:Nuclear transport in vitro. 261 52

The effects of thyroid hormone on nuclear-encoded mitochondrial inner membrane proteins were investigated by in vitro translation of the endogenous mRNA present in a postmitochondrial fraction from the livers of rats treated in vivo with hormone. The levels of the mRNAs were estimated by quantitative immunoabsorption of the translation mixture. Total protein synthesis was increased 2.6-fold after 4 days of in vivo hormone treatment, but only 10-15% of the polypeptides were dramatically altered (greater than 5-fold). Among the most highly elevated were cytochrome c1 (greater than 10-fold increase) and the Rieske iron-sulfur protein of the cytochrome bc1 complex. Other inner membrane proteins (core protein 1, beta subunit of F1 ATPase, subunit IV of cytochrome oxidase, 3-hydroxybutyrate dehydrogenase) and non-mitochondrial proteins (rat serum albumin, beta 2-microglobulin) were not altered significantly by hormone treatment. Cytochrome c1 and the Rieske protein increased after 12 h of hormone treatment, a relatively early response in mammalian mitochondrial biogenesis. The possible significance of this response for the regulation of mitochondrial synthesis and assembly is discussed.
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PMID:Thyroid hormone regulation of nuclear-encoded mitochondrial inner membrane polypeptides of the liver. 277 68


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