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)

Each milligram gluten protein isolated from bread contains 0.03-0.06 mumol calcium. On theoretical grounds we have concluded that this calcium quantity is bound to the free carboxyl groups not participating in peptide bonds of dicarbonic aminoacids, especially glutaminic acid, making up a large proportion within the aminoacids of gluten. After treatment with EGTA, a well-known calcium complex forming compound, two gluten fractions can be distinguished: water-soluble gluten-ES, and gluten-EP soluble in acetic acid. The aminoacid composition of gluten-ES is similar to that of unfractionated gluten. It is rich in aminodicarbonic acid (glu), aminodicarbonic acid amide (gln) and proline. Further properties of gluten-ES are: immunological similarity to gluten; a molecular mass of 36 000 dalton; an absorption maximum at 275.6 nm; a Ca2+-binding capacity of 0.72 mumol Ca2+/mg protein as measured by atomic absorption spectrophotometry and by Ca2+ ion selective electrode; inhibitory effect of a small quantity (25-30 micrograms) of the compound on the Ca2+-Mg2+ dependent ATPase and Ca2+-uptake of fragmented sarcoplasmatic reticulum. Preliminary experiments have demonstrated that gluten-ES has an influence on other calcium ion mediated systems like actomyosin superprecipitation. We put forward the hypothesis that by its Ca2+-binding capacity, gluten-ES is capable of influencing the level of free calcium and may thus play a part in the pathomechanism of coeliac disease.
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PMID:Isolation and physicochemical and functional properties of a calcium binding gluten fraction. 293 Oct 90

1. The effect of gossypol acetic acid upon the energy-producing system of isolated liver mitochondria was studied. Gossypol was found to exert an uncoupling effect. 2. Oxygen consumption and ATPase activity were stimulated only when a monovalent alkali metal cations was present. 3. The mitochondrial proton gradient, produced by the enzymatic hydrolysis of ATP, was lower in the gossypol-treated mitochondria than in the control experiments. 4. It is proposed that gossypol stimulates oxygen consumption and the ATPase activity in mitochondria by a protonophoretic effect and a cation translocation process.
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PMID:Biochemical effects of gossypol in isolated mitochondria: monovalent cations and ATPase activity. 296 42

Formation of the phosphorylated intermediate (ECaP) of the human erythrocyte Ca2+-stimulated ATPase (Ca2+-ATPase) was more rapid and reached steady state sooner at 400 microM-Ca2+ than at 1 microM-Ca2+. Calmodulin increased the apparent rate of ECaP formation at 1 microM-Ca2+, whereas at 400 microM-Ca2+, calmodulin decreased the steady-state level of the ECaP without affecting its apparent rate of formation. Removal of endogenous Mg2+ with trans-1,2-diaminocyclohexane-NNN'N'-tetra-acetic acid, which decreased both the velocity and Ca2+-sensitivity of the Ca2+-ATPase, did not alter the Ca2+-sensitivity or the apparent rate of formation of ECaP. ECaP formation at high Ca2+ concentrations was not affected by Mg2+ concentrations as high as 1 mM, and the ECaP could be dephosphorylated by ADP and ATP along either the forward or reverse pathways. The results suggest that high Ca2+ concentrations inhibit Ca2+-ATPase activity by preventing dephosphorylation of the E2P complex, rather than by inhibition of the transformation from E1CaP ('high-Ca2+-affinity' ECaP) to E2CaP ('lower-energy' ECaP).
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PMID:Effects of Ca2+, Mg2+ and calmodulin on the formation and decomposition of the phosphorylated intermediate of the erythrocyte Ca2+-stimulated ATPase. 296 71

The activity of three forms of ATPase were examined in fractions of the brain of the gerbil treated with ethylene glycol-N-N-tetra-acetic acid (EGTA) under a variety of conditions of primary and secondary (reflow) ischemia. In animals which were unilateral ischemic (ligation of the right common carotid), damage to Na+, K+-ATPase alone was observed only after at least 6 hr of ischemia had elapsed. The phenomenon occurred in only symptomatic gerbils and was absent in animals which were either asymptomatic or only displayed partial neurological symptoms. Under conditions of bilateral cerebral ischemia, in which both carotid arteries were clamped, only irreversible ischemia (60 min) followed by reflow, was associated with highly significant damage to cerebral Na+, K+-ATPase. In regional studies of the forebrain involving ischemia for 60 min plus 30 min reflow, damage to Na+, K+-ATPase was evident in the cerebrum, hippocampus, striatum and thalamus, while the hypothalamus and olfactory bulb were spared. Pretreatment of gerbils with allopurinol, clonazepam or combinations of thiopental plus either indomethacin or methylprednisolone offered protection to cerebral Na+, K+-ATPase subsequent to secondary ischemia. With only minor exceptions (striatum) neither Ca2+, Mg2+- nor Mn2+-ATPase were altered by stroke or treatment with drugs.
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PMID:Classification of ischemic-induced damage to Na+, K+-ATPase in gerbil forebrain. Modification by therapeutic agents. 299 3

Rats were treated orally with gossypol acetic acid at 30 or 10 mg/kg daily, 6 days a week, for 8, 12, 14 or 16 weeks. At the end of each treatment regimen, treated rats and an equal number of control rats were killed for histological and histochemical studies. From 8 weeks onward, as a result of the treatment, the tubular lumen of the corpus epididymides became narrowed with thickened pseudostratified epithelium and there was a reduction in the amount of spermatozoa. There was an increase in esterase, alkaline phosphatase, acid phosphatase and ATPase activity. These changes increased in intensity with the duration of treatment. Scanning electron microscopic examinations of the corpus epididymides of rats treated for 16 weeks, compared with those of controls, revealed similar changes, namely, narrowing of the tubular lumen, thickening of the pseudostratified epithelium and reduction in the number of spermatozoa.
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PMID:Effect of gossypol acetic acid on the epididymis: histochemical and scanning electron microscope studies. 304 Nov 22

Zinc, lead and cadmium in the form of chloride salts when added to a standard assay system containing 80 X 10(-6) ejaculated washed human spermatozoa caused a dose and duration-dependent inhibition of their motility. The activity of certain key enzymes of carbohydrate and energy metabolism, viz, glycogen phosphorylase, glucose-6-phosphatase, fructose-1, 6-diphosphatase, glucose-6-phosphate isomerase, amylase, Mg2+- dependent ATPase and lactic and succinic acid dehydrogenases were also found to be inhibited. The order of inhibitory effects of the heavy metals were zinc less than lead less than cadmium. The metal chelating agent, ethylene diamine tetra-acetic acid (EDTA, disodium salt) also interfered with the spermatozoal motility and inhibited the enzyme activities.
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PMID:Effect of selected metal ions on the motility and carbohydrate metabolism of ejaculated human spermatozoa. 314 74

Nine hydrophobic carbodiimides were synthesized and their chemical reactivities (towards acetic acid) and inhibitory capacities (towards the (Ca2+ + Mg2+)-ATPase were measured. No correlation between chemical reactivity and inhibitory efficacy emerges, but a significant effect of molecular bulk on reactivity towards the calcium-protectable carboxyl groups of the ATPase is noted: methyl-substituted compounds inhibit the enzyme in the presence of Ca2+, while aryl- or cyclohexyl-substituted compounds do not inactivate in the presence of Ca2+.
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PMID:Inhibition of (Ca2+ + Mg2+)-ATPase by carbodiimides. A structure-activity study. 315 70

The hepatic microsomal Ca2+- and Mg2+-dependent ATPase phosphoenzyme intermediates were distinguished by using the chelators EGTA and CDTA (trans-cyclohexane-1,2-diamine-NNN'N'-tetra-acetic acid). The Ca2+-ATPase intermediate is a hydroxylamine-labile base-labile 125 000-Mr phosphoprotein. The Mg2+-ATPase intermediate is a hydroxylamine-stable base-stable 30 000-Mr phosphoprotein. This enzyme intermediate probably reflects the large basal ATPase activity of hepatic microsomal fraction. It is dependent on Mg2+, since formation of the phosphoenzyme is abolished in the presence of CDTA. Under these conditions, the basal ATPase activity is dramatically decreased. These data demonstrate two separate and distinct enzymes which are responsible for the two ATPase activities of hepatic microsomal fraction. Furthermore, these data indicate that more meaningful data about the microsomal Ca2+-ATPase might be obtained if the free ion concentrations are controlled with CDTA.
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PMID:Phosphorylated intermediates of two hepatic microsomal ATPases. 315 73

1. A mechanical tissue chopper was used to obtain 35-75 mg explants from 21- to 28-day-old chick liver to determine assay conditions (substrates, buffers, time), regulators (metals and hormones) and points of endogenous regulation of de novo lipogenesis (ATPase, reductive potential and protein phosphorylation). High- and low-bicarbonate-based buffers (Earl's balance salts, EBSS and Hanks' balanced salts, HBSS; respectively) were used in conjunction with sources and types of bovine serum albumin (BSA), divalent cations (Mg2+ or Ca2+), substrate (glucose or acetate) and hormones (insulin and catecholamines). 2. Neither EBSS nor HBSS changed in vitro lipogenesis, CO2 or glucose production when 20 mM HEPES was added to these salts. 3. Neither the presence nor the source of BSA (Sigma or Armour) affected metabolism. In contrast, reducing the vessel reaction surface area (5.1 vs 10.5 cm2) decreased metabolic rates. 4. Acetate was more readily utilized than glucose as an in vitro fatty acid precursor. Use of glucose was complicated by production of glucose from endogenous precursors and by label recycling. Divalent cations (Mg2+ or Ca2+) had little affect upon lipogenesis. 5. Chicken insulin (50 ng/ml) did not affect lipogenesis; however, incorporation of acetate into fatty acids was decreased by dibutyryl cyclic AMP. A catecholamine-induced decrease in vitro lipogenesis indicates that major points of regulation are under control of phosphorylation-dephosphorylation steps.
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PMID:Measurement of glucose and lipid metabolism in avian liver explants. 342 27

Inhibition of renin secretion from incubations of rat kidney cortex by angiotensin II (AII), ouabain and K+ depletion, depended on the presence of external Ca2+. AII inhibition of isoprenaline-stimulated renin secretion was only partially dependent on external Ca2+. Ouabain and K+ depletion inhibited isoprenaline-stimulated renin release but only in the presence of external Ca2+. Since, in Ca2+-free medium, isoprenaline stimulated renin release when the Na+/K+-ATPase was blocked, isoprenaline probably does not act through the Na+/K+-ATPase. Lanthanum blocked the stimulation of renin release by isoprenaline. Ethylenediamine tetra-acetic acid (EDTA) and ethyleneglycol-bis-(beta-amino-ethyl ether) N,N'-tetra-acetic acid (EGTA) increased renin secretion to a similar degree in Ca2+- and Mg2+-free buffer. When Mg2+ was present the effect of EGTA, but not EDTA, was considerably reduced. Verapamil reduced the fall in basal renin secretion in normal but not Ca2+-free buffer. Verapamil did not block the inhibitory effects of AII or ouabain and did not alter the stimulation of renin secretion by isoprenaline. Bay K 8644 inhibited renin secretion from cortex incubated in medium containing 15 mM K+ and this was dependent on extracellular Ca2+. In normal buffer (5.9 mM K+) Bay K 8644 increased renin secretion.
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PMID:Stimulation and suppression of renin release from incubations of rat renal cortex by factors affecting calcium flux. 354 5


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