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 properties of divalent metal.ADP.vanadate (V(i)) complexes of the 6S extended and 10S folded conformations of gizzard myosin before and after UV irradiation have been studied. The half-lives of both 6S and 10S myosin.MgADP.V(i) complexes in the dark at 0 degrees C are on the order of 2 weeks. Brief irradiation with UV light, however, photomodified the enzyme as suggested by changes in the NH(4+)-, K(+)-, and Ca(2+)-ATPase activities, and destabilized the complexes. The 6S complex, when irradiated, released ADP and V(i) rapidly (t1/2 less than or equal to 1 min) as has been observed in comparable experiments with skeletal myosin subfragment 1 (S1) [Grammer et al. (1988) Biochemistry 27, 8408-8415]. The irradiated 10S complex released approximately 20% of the ADP and V(i) rapidly (t1/2 less than or equal to 1 min), but the remainder stayed trapped, possibly as the vanadyl (VO2+).ADP complex, for much longer times (t1/2 approximately 8 h). The site of photomodification was sought by reducing both photomodified 6S and 10S myosin with NaB3H4. Amino acid composition analyses identified [3H]serine as the only labeled residue(s), suggesting that the hydroxymethyl group of serine had been oxidized to an aldehyde as shown previously for photomodified skeletal myosin S1 [Cremo et al. (1989) J. Biol. Chem. 264, 6608-6611]. The 29-kDa NH2-terminal tryptic peptide from the heavy chain was found to contain essentially all of the [3H]serine. Preparations of 6S and 10S [3H]myosin were digested exhaustively with trypsin. An identical [3H]peptide was purified from each preparation and its sequence determined to be Glu169-Asp-Gln-Ser-Ile-Leu-(Cys)-Thr-Gly-[3H]Ser-Gly-Ala-Gly-Ly s183.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Stability and photochemical properties of vanadate-trapped nucleotide complexes of gizzard myosin in the 6S and 10S conformations: identification of an active-site serine. 138 24

Acetaldehyde, which is present in significant concentrations in cigarette smoke and is elevated during alcohol ingestion, has been demonstrated to impair mucociliary clearance of the lung. Acetaldehyde is also known to impair protein function through the formation of acetaldehyde-protein adducts. We hypothesized that acetaldehyde impairs bronchial epithelial cilia motion by inhibiting cilia dynein adenosinetriphosphatase (ATPase) activity through the formation of acetaldehyde adducts with cilia proteins. Acetaldehyde induced concentration- and time-dependent slowing of cilia beating and cilia-derived dynein ATPase activity in primary cultures and isolated axonemes of bovine airway epithelial cells. Cilia slowing and ATPase inhibitory effects were also observed with related aldehydes but not with ethanol. Acetaldehyde binding, assessed by gel electrophoresis using [14C] acetaldehyde, was demonstrated to occur with the dynein heavy chains and with tubulin and closely paralleled ATPase inhibition. We conclude that acetaldehyde directly impairs bronchial cilia function causing slowing of cilia beating, inhibits cilia dynein ATPase activity, and binds to cilia proteins critical for motion including dynein and tubulin. These data suggest that acetaldehyde-induced cilia dysfunction may be related to direct cilia ATPase inactivation and adduct formation with cilia dynein and tubulin. This may be an important mechanism by which airway host defenses are impaired in clinical settings where acetaldehyde exposure occurs, e.g., with cigarette smoking and alcohol ingestion.
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PMID:Acetaldehyde-mediated cilia dysfunction in bovine bronchial epithelial cells. 182 52

Osteopenia is a recognized complication of diabetes mellitus in humans and experimental animals. We recently found that tetracyclines prevent osteopenia in the streptozotocin-induced diabetic rat and that this effect was associated with a restoration of defective osteoblast morphology (Golub et al., 1990). The present study extends these initial ultrastructural observations by assessing osteoblast function in the untreated and tetracycline-treated diabetic rats. After a 3-week protocol, non-diabetic control and diabetic rats, including those orally administered a tetracycline, minocycline (MC), or a non-antimicrobial tetracycline analog (CMT), were perfusion-fixed with an aldehyde mixture; the humeri were dissected and processed for ultracytochemical localization of alkaline phosphatase (ALPase) and Ca-ATPase activities. Some rats from each experimental group received an intravenous injection of 3H-proline as a radioprecursor of procollagen, and the humeri were processed for light microscopic autoradiography. In addition, the osteoid volume in each experimental group was quantitatively examined by morphometric analysis of electron micrographs. During the diabetic state, active cuboidal osteoblasts in the endosteum of control rats were replaced by flattened bone-lining cells that contained few cytoplasmic organelles for protein synthesis (Golgi-RER system), and active transport (mitochondria). Treating diabetic rats with MC, and even more so with CMT, appeared to "restore" osteoblast structure. During diabetes, bone-lining cells incorporated little 3H-proline or secreted little labeled protein and produced only a very thin osteoid layer. Tetracycline administration to the diabetics increased both the incorporation of 3H-proline by osteoblasts and their secretion of labeled protein toward the osteoid matrix, in a pattern similar to that seen in the non-diabetic controls.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Tetracycline administration restores osteoblast structure and function during experimental diabetes. 183 18

Immunocytochemistry was used to investigate the localization of F1 ATPase in mitochondria of cryosections of adult mouse heart muscle cells. The initial aldehyde fixation was the only denaturation step for antigens. The fine structure was preserved with contrast enhancement as the sections were maintained hydrated, with the advantage that the entire procedure is completed in one working day. The reaction was highly specific, and entire mitochondria were labeled with the Protein A-gold complex. A new analytical technique, electron spectroscopic imaging (ESI), contributed to a better visualization of the localization of the F1 factor.
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PMID:Immunoelectron localization of mitochondrial F1 factor in cryosections of heart muscle cells. 188 2

Several alterations of the small-intestinal morphology and function have been documented after alcohol ingestion. There are morphologic changes macroscopically and microscopically after acute alcohol administration in the proximal part of the small intestine, which are quickly reversible. There are no macroscopic changes and, in most patients, very discrete light microscopic changes in the small intestine after chronic alcohol ingestion. The ultrastructural changes are, however, profound, as seen by both transmission and scanning electron microscopy. The permeability is probably increased, permitting entrance of possible noxious agents, which may explain some of the extraintestinal tissue damage observed in chronic alcoholism. The transit is increased, at least after acute alcohol administration, perhaps contributing to the diarrhea commonly seen after heavy drinking. Several of the enzymes located in the brush border are affected; lactase activity can be depressed and perhaps result in a transient milk intolerance in predisposed individuals. The activity of GGT is increased and may partly account for the GGT elevation in serum after heavy drinking. Other enzymes, such as Na(+)-K(+)-ATPase, can be inhibited and result in a decreased absorption of substances that require active, energy-dependent transport mechanisms. The secretion of water and electrolytes may be increased (an effect on cAMP?). The absorption of several nutrients, vitamins, and other elements is disturbed. The bacterial flora is increased and changed, which may give rise to symptoms and also increase the production of acetaldehyde by bacterial metabolism of ethanol. Acetaldehyde is more toxic than ethanol, and an increased concentration of acetaldehyde can possibly accentuate the damage to the liver and other organs. The bacterial overgrowth can possibly cause endotoxinemia. Although studies on alcohol-related intestinal alterations have been relatively sparse, the acute and chronic effects of alcohol thus seem to be considerable. From available results it is, however, difficult to draw any definite conclusions about the clinical importance of many of the findings. Future research will need to study the relationship between, for example, the chronic morphologic changes, the absorptive dysfunction, and permeability alterations, on the one hand, and the gastrointestinal symptoms, the extraintestinal damage, and various deficiencies, on the other hand.
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PMID:Alcohol and the small intestine. 200 95

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

Using isolated healthy human leucocytes and erythrocytes as model cells, we investigated the inhibitory effect of ethanol, its metabolites and of other toxic alcohols on the active fluxes of rubidium (Rb: equivalent to K) and sodium (Na), and on Na,K-ATPase activity. Ethanol (80 mmol X l-1) inhibited total and ouabain-sensitive 86Rb influx and 22Na efflux in leucocytes, this being dose-related for total, ouabain-sensitive and ouabain-insensitive fluxes at higher concentrations. In erythrocytes inhibition occurred at 20 mmol X l-1 for 86Rb influx, dose-related at higher concentrations as for leucocytes. 22Na efflux was inhibited at 80 mmol X l-1 and above. Acetaldehyde (0.1 and 0.2 mmol X l-1), 1,2-propanediol (0.8 mmol X l-1) and 2,3-butanediol (0.4 mmol X l-1) inhibited all fractions of 86Rb influx in erythrocytes, but not in leucocytes. Methanol, 2-propanol and 1,2-ethanediol (16 and 32 mmol X l-1) inhibited 86Rb influx in erythrocytes, but not in leucocytes. The order of potency was 2-propanol greater than 1,2-ethanediol greater than methanol. Na,K-ATPase activity was inhibited in lysed leucocyte and erythrocyte preparations only at very high concentrations of the alcohols--suggesting that inhibition is due to an alteration in membrane structure and not to a direct effect on the enzyme.
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PMID:The acute in vitro effect of ethanol, its metabolites and other toxic alcohols on ion flux in isolated human leucocytes and erythrocytes. 242 65

Ca-dependent ATPase activity in the rat anterior pituitary was demonstrated in 50-microns tissue slices of aldehyde-fixed tissue with the medium of Takano et al. (Cell Tissue Res. 243:91. 1986).--The outer surface of the plasma membrane of the parenchymal as well as the folliculo-stellate cells was lined with lead precipitate. The reaction deposit was particularly well localized in intercellular spaces both between two parenchymal cells, and between a parenchymal and a folliculo-stellate cell. A fine reaction deposit was also seen in the endoplasmic reticulum and Golgi apparatus of some parenchymal cells. Elimination of Ca2+ from the tissue and the substrate medium drastically reduced the amount of reaction product. If ATP was omitted or replaced by sodium beta-glycerophosphate, no reaction product was seen. Changing the Ca2+ concentration or addition of Mg2+ to the standard medium caused a decrease in reaction intensity. Substitution of Mg2+ for Ca2+ resulted, again in well-localized lead deposition which we attribute to the activity of another enzyme. We suggest that the activity we described in the membrane of glandular cells may correspond to the enzyme involved in the long-term regulation of intracellular Ca2+ level.
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PMID:Ultrastructural study of the Ca2+-dependent ATPase activity in rat adenohypophyseal cells. 252 36

Maternal alcohol consumption produces various abnormalities in the offspring, termed fetal alcohol syndrome. We investigated various biochemical modifications occurring in the brain and the liver of pups born to alcohol-consuming rats. The parameters analysed were: superoxide dismutase, a protector against free radicals injury, enolase isoenzymes as markers of nerve cell maturation, glutamine synthetase involved in ammonia detoxification, alcohol and aldehyde deshydrogenases in order to evaluate the contribution of acetaldehyde teratogenicity and ATPase activities involved in ion and neurotransmitter transport. Activities of all these enzymes were decreased in the brain even when alcohol was withdrawn from the mother diet either during pregnancy or lactation. Activities were also decreased in the liver, except enolase and alcohol deshydrogenase activities, which were increased, suggesting possible adaptative events in the presence of alcohol. It seems likely that the multiple alterations observed in experimental fetal alcohol syndrome may be caused by free radicals following decreased superoxide dismutase activity in addition to the toxicity of alcohol and its metabolites.
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PMID:An experimental study of fetal alcohol syndrome in the rat: biochemical modifications in brain and liver. 256 12

The inhibition of myofibrillar ATPase activity by aldehyde fixation in tissue pieces of myocardium of the rat was measured by scanning histophotometry. The relative amount of the final reaction product of the histochemical method for ATPase (Padykula and Herman 1955) was taken as a measure for the enzyme activity. Along scanning lines in slides from the surface to the centre of tissue block, a higher activity was found in the centre in contrast to the marginal zone. Compared with the centre of the block (approximately equal to 100%), in the marginal region a loss of about 40% (in paraformaldehyde PFA) and of 75% (in glutaraldehyde GA) was found, the latter with a sharp decline between the marginal zone and the central part. For quantitative enzyme histochemistry by histophotometry unfixed material is recommended.
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PMID:Histophotometrical measurements concerning the distribution of myofibrillar ATPase activity within the tissue block after aldehyde fixation. 296 14


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