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

---

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

Alterations in the levels of selected enzymes have been studied in the liver, kidney and brain of mouse following mercuric chloride (1 mg/Kg body wt./d) administration for 10, 20 and 30 d. The activity of acid phosphatase increased in all the tissues, the highest increase was recorded in the kidneys which showed as much as 4.5 fold elevation following mercuric chloride administration for 30 d. Although the alkaline phosphatase activity in the liver and the brain increased following HgCl2 administration, the kidneys experienced a tremendous decline in this enzyme following the same treatment. Mercury-induced changes in ATPase were complex inasmuch as the nature and magnitude of these changes varied with the tissue as well as the duration of the treatment. Whereas the liver ATPase declined after all the treatment intervals, this enzyme increased in the kidney and brain following administration of HgCl2 for 10 d. However, both the kidneys and brain registered a substantial fall in ATPase activity when HgCl2 administration was continued for 30 d. The levels of both glucose-6-phosphatase and succinic dehydrogenase decreased in all the tissues following HgCl2 administration. Invariably, the magnitude of decrease was the highest after 30 d treatment with HgCl2.
...
PMID:Enzyme changes in the brain, liver and kidney following repeated administration of mercuric chloride. 302 11

The effect of mercury chloride (HgCl2) and methyl mercury chloride (MeHg) on brain synaptosomal Na+/K+-ATPase was determined in vitro. It was shown that HgCl2 is a more powerful inhibitor than MeHg. The IC50 were 5 X 10(-7) M for HgCl2 and 2.3 X 10(-6) M for MeHg. A non-competitive type of inhibition was observed with the two mercurials. Removal of contaminating lipids with the non-ionic detergent Lubrol did not affect the inhibition of either mercurial. It is concluded that non-essential lipids do not play a significant role in the inhibitory effect of MeHg and that the potency of these mercurials on to inhibit brain synaptosomal Na+/K+-ATPase largely depends on their capacity to block sulfhydryl groups.
...
PMID:Studies on the inhibition of brain synaptosomal Na+/K+-ATPase by mercury chloride and methyl mercury chloride. 302 27

Cathepsin B was purified from rabbit skeletal muscle by ammonium sulfate fractionation and successive chromatographies on Sephadex G-75, phosphocellulose, peptide-conjugated Sepharose, DEAE-Toyopearl and Sephadex G-100. The purified enzyme gave a single protein band on SDS/polyacrylamide gel electrophoresis. The enzyme did not abolish the Ca sensitivity of the ATPase activity of myofibrils. The molecular mass of the enzyme was found to be 27 kDa on gel filtration and SDS/polyacrylamide gel electrophoresis. The optimum pH for the hydrolysis of N alpha-benzoyl-DL-arginine-beta-naphthylamide was 6.5. The enzyme was stable in the range of pH 4.5-5.5. Tetrathionate reacted with thiol groups of the enzyme reversibly so that it stabilized the enzyme. The enzyme was strongly inhibited by iodoacetate, HgCl2, antipain, leupeptin, N alpha-p-tosyl-L-lysine chloromethane and L-tosylphenylalanylchloromethane, but not by pepstatin or trypsin inhibitor.
...
PMID:Purification and some properties of cathepsin B from rabbit skeletal muscle. 333 70

Effect of sublethal concentrations, 0.088, 0.044, 0.029, 0.022 and 0.0176 mg HgCl2 per liter (1/5, 1/10, 1/15, 1/20, and 1/25 fractions of 96-h LC50) on Na+-K+, Mg2+, and total ATPase activities in brain, gills, kidney and liver of Notopterus notopterus have been studied after 30 days exposure. Na+-K+ ATPase were inhibited maximally and significantly in brain and minimally and insignificantly in liver. Mg2+ ATPase was inhibited maximally and significantly (P less than 0.01) in brain and minimally and insignificantly in kidney. The relative inhibition of total, Na+-K+ and Mg2+ ATPases for the tissues studied were brain greater than gill greater than kidney greater than liver. At the concentration (1/25 fraction) the enzyme activity returned to the normal range.
...
PMID:In vivo effect of mercuric chloride on tissue ATPases of Notopterus notopterus. 613 59

p-Aminohippurate (PAH) uptake by teased flounder renal tubules was concentrative, Na-dependent, dependent on aerobic metabolism and inhibited by competitor organic anions and ouabain. Dose-response data for ouabain inhibition of PAH transport and tubule Na,K-adenosine triphosphatase (ATPase) activity were identical. In ouabain-treated tubules, reductions in PAH uptake correlated with alterations in total tissue Na and K even though both were not affected during the first 5 to 10 min of ouabain exposure. No such delay was found with HgCl2 and, as with ouabain, reductions in transport correlated well with alterations in tissue Na and K. Tissue respiration data indicated that low concentrations of HgCl2 rapidly affected the Na,K-ATPase. With higher HgCl2 concentrations, intracellular metabolic sites appeared to be affected. Transport studies with ouabain-poisoned tubules and plasma membrane vesicles indicated that the energetically uncoupled PAH carrier(s) were affected by HgCl2, but carrier sensitivities to Hg were lower than for the Na,K-ATPase. The data indicate that HgCl2 inhibits PAH transport primarily by reducing ion gradients that drive PAH transport. Both inhibition of Na,K-ATPase and increases in membrane permeability to Na and K appear to be involved.
...
PMID:Heavy metal inhibition of p-aminohippurate transport in flounder renal tissue: sites of HgCl2 action. 627 Mar 7

The inhibitory effect of mercuric chloride on mouse kidney enzymes and the treatment of this inhibition with some thiol-containing compounds, e.g., dithiothreitol (DTT), dimercaptosuccinic acid (DMS) and D-penicillamine (Pen) was examined. To produce a significant inhibition of renal enzymes in vivo, it was necessary to administer 5 mg Hg/kg/day, s.c., once daily for 3 doses, and to sacrifice the animals 1 day after the last injection. With this Hg dose, microsomal Mg2+-Na+-K+-ATPase, mitochondrial Mg2+-HCO-3-ATPase and supernatant carbonic anhydrase activities decreased to about 30%, 70% and 60% of normal values, respectively. Combined administration of DTT (5-20 mg/kg, i.p.) and DMS (5-20 mg/kg, i.p.) with HgCl2 restored the enzyme activities to near normal or normal levels in parallel to the administered doses. The effect of Pen was slightly less than that of the above 2 compounds. This may be due to the number of thiol radicals, as Pen is a monothiol and the other 2 compounds are dithiol compounds. Since the toxicity of DMS is very low compared with DTT, DMS may be more suitable for the treatment of mercury poisoning.
...
PMID:The protective effects of thiol-containing compounds on mercuric chloride-induced acute inhibition of enzymes from mouse kidney. 632 Apr 97

Acute effects of methylmercuric chloride and mercuric chloride on thyroidal functions were examined. The organic mercurial concentration of 4 x 10(-5) M inhibited by 50% of Na+K+ATPase in the membraneous preparation from the hog thyroid, and 6 x 10(-7) M of the inorganic mercurial showed the same extent of the inhibition. The Mg2+ ATPase activity in the preparation was neither affected by CH3HgCl up to a concentration of 2 x 10(-3) M, nor by HgCl2 up to 1 x 10(-4) M. After an intraperitoneal injection to mice of 5 micrograms of mercurial per gram body weight daily for 2 consecutive days, the 4-hour and the 24-hour uptakes of 131I by the thyroids were partially reduced by both organic and inorganic mercurials. A significant reduction in percentages of labeled iodothyronines was demonstrated to suggest that mercurial may cause a coupling defect in the synthesis of iodothyronines. Incubation of hog thyroglobulin with 8 x 10(-3) M of methylmercuric chloride caused no observable aberration in slab disc electrophoreogram, but the protein was apparently denatured by the same concentration of mercuric chloride suggesting that thyroglobulin may carry a large binding capacity against either mercurial, but the inorganic mercurial can be more potent denaturant of the protein. The in vitro lysosomal hydrolysis of the mercurial-pretreated rat thyroglobulin which was labeled with 125I in vivo and fortified with the carrier hog thyroglobulin was not affected, but the direct addition of either mercurial in the medium resulted in a significant inhibition of the proteolytic action. Iodotyrosine deiodinase in the thyroid was inhibited by both mercurials in in vitro and in vivo systems. A partial reduction in the serum bound 131I-iodide in both mercurial treated groups was observed at 4 hours and 24 hours after the radioiodide administration. The blood thyroxine levels estimated by radioimmunoassay were quite reduced in the inorganic mercurial treated group and also moderately reduced in the methylmercurial treated group, indicating that the hormone secretion was affected by mercurials.
...
PMID:Effects of organic and inorganic mercurials on thyroidal functions. 645 81

Mediated D-glucose and cycloleucine uptakes by killifish intestinal slices and everted sacs were reduced in a dose- and time-dependent manner by HgCl2 exposure, but nonmediated components of nutrient uptake were not affected. Transport processes in intestinal slices from sea water and fresh water-adapted fish exhibited identical sensitivities to HgCl2. The inhibitory effects of mucosal plus serosal exposure (slices) were no greater than the effects of mucosal exposure alone (sacs), indicating that primary inhibitory sites were on the brush border membrane of the tissue. One- to 5-min slice exposures (which caused substantial inhibition of nutrient transport) did not affect cellular water or electrolyte levels (indirect measures of Na,K-adenosine triphosphatase activity). With brush border membrane vesicles from killifish and flounder small intestine, HgCl2 affected only the Na-dependent component of D-glucose up-take. Vesicle Na permeability was not increased by HgCl2 exposure. Kinetic studies with killifish slices and flounder vesicles indicated that both Km and Vmax for glucose transport were affected by HgCl2. Taken together, these findings indicate that HgCl2 blocks intestinal nutrient transport by interacting directly with brush border membrane transport proteins; the kinetic data indicate that multiple sites on these proteins are probably affected.
...
PMID:HgCl2 inhibition of nutrient transport in teleost fish small intestine. 745 9

Acute inhibitory effects of mercuric chloride on the activities of several enzymes from rat duodenal mucosa and kidney cortex and the protection provided by 2,3-dimercaptopropane-1-sulfonate (DMPS) were examined. Activities of carbonic anhydrase in homogenate, brush border and cytosol and of Mg(2+)-dependent, HCO3-stimulated ATPase in homogenate and brush border of duodenal mucosa and kidney cortex and activities of kidney microsomal Mg(2+)-dependent, Na(+)-K(+)-stimulated ATPase were all decreased following administration of HgCl2 (1-3 mg Hg/kg body weight s.c. once daily for 3 days). Decreases occurred generally in a dose-dependent manner and went back to near normal or normal levels by the combined administration of 20 and 30 mg DMPS/kg per day for 3 days. The concentration of serum urea nitrogen was increased about 8 times by the administration of 2 mg Hg/kg and restored to normal by the concomitant administration of 30 mg DMPS/kg. After the administration of 2 mg Hg/kg per day for 3 days, about half of the renal cortical proximal tubuli were necrotic. Administration of 30 mg DMPS/kg restored these changes to almost normal. The results suggest that DMPS is useful in mitigating acute Hg poisoning and that part of the protective effect of DMPS on enzyme damage induced by Hg poisoning may be due to its chelating action.
...
PMID:Protective effects of 2,3-dimercaptopropane-1-sulfonate on mercuric chloride-induced acute inhibition of enzymes from rat duodenal mucosa and kidney cortex. 813 22

Although lysosomes maintain large pH gradients and may be subjected to significant osmotic gradients in vivo, little is known about their passive permeability properties. In recent studies, vacuolar H(+)-adenosine-triphosphatases (ATPases), such as those found in lysosomes, have been suggested to act as water channels. In addition, the erythrocyte and proximal tubule water channel CHIP28 is present on the plasma membrane of proximal tubule cells and may undergo endocytosis so that it is incorporated in lysosomes. We therefore examined water, proton, and small nonelectrolyte permeabilities in freshly purified lysosomes from rat renal proximal tubule. Lysosomes were purified by differential and Percoll gradient centrifugation. The preparation contained only lysosomes when examined by electron microscopy. Moreover, analysis by flow cytometry showed virtually all particles to be positive for acid phosphatase and cathepsin B activities. Permeabilities were measured on a stopped-flow fluorimeter by monitoring the self-quenching or pH-sensitive quenching of entrapped fluorescein derivatives. Osmotic water permeability (Pf) averaged 0.011 +/- 0.003 cm/s (n = 6), a value similar to that of biological membranes containing water channels. However, Pf was insensitive to the organic mercurial reagent p-chloromercuribenzene-sulfonate and to HgCl2 and exhibited an activation energy of 10.8 +/- 0.8 kcal/mol. These results indicate that water flux in lysosomes occurred via the lipid bilayer, and not via water channels. Addition of ATP led to lysosomal acidification (proton flux = 4.6 +/- 0.8 x 10(-11) mmol H+.s-1.cm-2), which was completely inhibited by 0.1 microM bafilomycin. Pf was insensitive to this agent as was the passive proton permeability (0.36 +/- 0.18 cm/s, n = 4). Permeabilities to small nonelectrolytes varied in proportion to the oil-water partition coefficient, confirming the applicability of Overton's rule to lysosomes. We conclude that proximal tubular lysosomes exhibit high Pf, which occurs via the lipid bilayer and not via vacuolar H(+)-ATPase.
...
PMID:Permeability properties of rat renal lysosomes. 830 10


<< Previous 1 2 3 4 5 6 Next >>

---