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)

1. The intracellular pH was measured in growing Clostridium pasteurianum with and acid-base equilibrium distribution method. [14C]Dimethyloxazolidinedione, [14]methylamine and [14C]acetic acid were used as "deltapH-indicators". During growth the extracellular pH decreased from 7.1 to 5.1; simultaneously the intracellular pH changed from 7.5 to 5.9. Thus, the intracellular pH was more alkaline than the extracellular pH by 0.4 to 0.8 pH-units. 2. This pH gradient (interior alkaline) was abolished by the proton conductor carbonylcyanide m-chlorophenylhydrazone and the ATPase inhibitor N,N'-dicyclohexylcarbodiimide. The pH gradient could not be demonstrated in cells depleted of an energy substrate. These results suggest that the pH gradient is formed by an ATPase-driven extrusion of protons from the cells rather than by a Donnan potential. 3. Growth of the organism was inhibited by low concentrations of both carbonylcyanide m-chlorophenylhydrazone (5 muM) and dicyclohexylcarbodiimide (5 muM). This finding suggests that the pH gradient is essential for the growing cell as it may be required for substrate accumulation and other types of transport processes.
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PMID:The internal-alkaline pH gradient, sensitive to uncoupler and ATPase inhibitor, in growing Clostridium pasteurianum. 0 Feb 37

1. The terminal phosphate of (gamma-32P)ATP is rapidly incorporated into cardiac sarcoplasmic reticulum membranes (0.7--1.3 mumol/g protein) in the presence of calcium and magnesium. Cardiac sarcoplasmic reticulum membranes catalize an ATP-ADP phosphate exchange in the presence of calcium and magnesium. 2. Half-maximum activation of the phosphoprotein formation and ATP-ADP phosphate exchange is reached at an ionized calcium concentration of about 0.3 muM. The Hill coefficients are 1.3. 3. Transphosphorylation and ATP-ADP phosphate exchange require magnesium and are maximally activated at magnesium concentrations close to or equal to the ATP concentration. 4. The phosphoprotein level is reduced to about 45% at an ADP/ATP ratio of 0.1. The rate of calcium-dependent ATP splitting declines, whilst the rate of the calcium-dependent ATP-ADP phosphate exchange increases when the ADP/ATP ratio is varied from 0.1 to 1. The sum of both, the rate of ATP splitting and the rate of ADP-ATP phosphate exchange remains constant. 5. Phosphoprotein formation and ATP-ADP phosphate exchange are not affected by azide, dinitrophenol, dicyclohexyl carbodiimide and oubain, whilst both activities are reduced by blockade of -SH groups localized on the outside of the sarcoplasmic reticulum membrane. 6. The isolated phosphoprotein is acid stable. The trichloroacetic acid denatured 32P-labelled membrane complex is dephosphorylated by hydroxylamine, which might indicate that the phosphorylated protein is an acyl-phosphate. 7. Polyacrylamide gel elctrophoresis (performed with phenol/acetic acid/water) of phosphorylated sarcoplasmic reticulum fractions demonstrates that the 32P-incorporation occurs into a protein of about 100000 molecular weight. 8. It is suggested that the phosphoprotein represents a phosphorylated intermediate of the calcium-dependent ATPase which formation occurs as an early step in the reaction sequence of calcium translocation by cardiac sarcoplasmic reticulum similar as in skeletal muscle.
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PMID:Characterization of cardiac sarcoplasmic reticulum ATP-ADP phosphate exchange and phosphorylation of the calcium transport adenosine triphosphatase. 0 67

1. Phenylglyoxal reacts rapidly with isolated myosin heads (subfragment 1) and induces two successive and distinguishable effects on their enzymic properties: first, a twofold activation of the Ca2+ and Mg2+-dependent ATPases with no effect onthe K+-ATPase followed by inhibition of the K+, Ca2+ and actin-activated Mg2+-ATPases. A specific protein-reagent reagent complex is formed during the second phase of the modification reaction (Ki approximately 5 x 10(-3) M). 2. ADP and ATP with or without cations provide efficient protection only against the loss of ATPase activities, suggesting that the second inhibitory process is occurring at or close to the active site. 3. On the basis of [14C]phenylglyoxal-labelling experiments and the composition of modified subfragment-1 derivatives, it is demonstrated that the sequential modification of two reactive arginyl residues is responsible for the observed activation-inhibition phenomena. Blocking of the first reactive residue produces a shift in the pH/activity curves related to the Ca2+ and Mg2+-dependent ATPases with an apparent activation effect. Modification of the second guanidino group does not destroy the affinity of the protein for the nucleotide substrates but does alter the nucleotide binding site as reflected in the inability of Mg2+. ATP to dissociate the modified subfragment-1--actin complex. It is concluded that electrostatic interactions between this positively charged group and the negatively charged ATP and ADP molecules may be critical for the hydrolytic efficiency of myosin heads. 4. After dissociation and separation of the polypeptide constituents of the protein in acetic acid medium, both labelled sites are found to reside in the heavy chain.
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PMID:Involvement of an arginyl residue in the catalytic activity of myosin heads. 4 10

5,6,7,8-tetrahydrocarbzzole-3-acetic acid (AH 2835) given to maternal rats throughout their gestation produces an experimental model of the autosomally inherited human infantile polycystic disease Potter type I in the rat foetuses. The affected animals have cystic lesions in their kidneys, liver and pancreas like those seen in the human. Evidence is presented for the aetiology of the experimental lesion being related to the action of AH 2835 on the specific activity of the ouabain sensitive (Na+ + K+)-ATPase of absorptive epithelia. It is noted that two cystic kidney diseases, the ocngenital nephrotic syndrome and infantile polycystic disease Potter type I are both inherited as autosomal recessive traits and are therefore likely to be caused by enzyme abnormalities, and that the compound AH 2835 can be used to produce experimental models of both of these diseases.
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PMID:Polycystic disease of kidney, liver and pancreas; a possible patholgenesis. 13 39

The histochemical activities of myofibrillar adenosine triphosphatase (ATPase), succinic dehydrogenase (SDH) and alpha glycerophosphate dehydrogenase (alpha-GPD) were studied in intrafusal muscle fibres of rat fast and slow muscles. The ATPase reaction was carried out after the three standard acid preincubations. The cold K2-EDTA preincubated ATPase reaction product was similar to that seen following the regular or alkali-preincubated ATPase reaction, except that the intermediate bag fibres exhibited much higher activity after cold K2-EDTA preincubation. Following either acetic acid solution or cold and room temperature K2-EDTA-preincubation, followed by the ATPase reaction, chain fibres of the fast muscles vastus lateralis and extensor digitorum longus exhibited a very low amount of reaction product as compared with those of the slow soleus. Veronal acetate and K2-EDTA preincubations (and equally preincubation in acetic acid solution) resulted in acid stable ATPase activity along the entire length of the typical bag fibres but only in the polar regions of the intermediate bag fibres. On the basis of differing alpha-GPD reaction, two sub populations of nuclear chain fibres were discovered in one spindle. It is a matter of conjecture, to what extent the histochemical differences of intrafusal fibres from fast and slow muscles reflects functional distinctions in the response to stretch of muscle spindles from fast and slow muscles.
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PMID:A histoenzymatic study of rat intrafusal muscle fibres. 15 74

The relationship between Na-K-ATPase activity and p-aminohippurate (PAH) transport was examined in renal cortical slices of mixed-breed rabbits by using ouabain to vary the level of Na-K-ATPase activity. Ouabain increased passive PAH uptake, measured in the presence of probenecid. Slice homogenate Na-K-ATPase activity was inhibited by 50% with about 2 X 10(-6) M ouabain. When the concentration was 10(-5) M or above, active PAH uptake was inhibited. Lower concentrations (10(-7) and 10(-6) M) of ouabain stimulated active PAH uptake. Acetate stimulated PAH uptake when medium ouabain was less than 10(-4) M. Ouabain, 10(-5) M and higher, caused intracellular K+ to fall and Na+ to rise. The changes in active PAH uptake observed with ouabain correlated much better with changes in intracellular K+ or Na+ levels (P less than 0.01) than with changes in slice homogenate Na-K-ATPase activity. Vmax for active PAH uptake decreased with 5 X 10(-5) M ouabain, and tended to increase with 10(-7) M ouabain. Ouabain did not alter Km for active PAH uptake. The data support the hypothesis that there is a functional link between active PAH transport and Na-K-ATPase activity. This linkage may be an indirect one mediated by changes in intracellular cation concentrations.
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PMID:Relationship between PAH transport and Na-K-ATPase activity in the rabbit kidney. 21 77

Ethanol and acetaldehyde, alone or in combination, at physiologic concentrations, significantly inhibit mitochondrial protein synthesis in vitro. Mitochondria from rats chronically fed ethanol also display a reduced rate of mitochondrial protein synthesis in vitro. This effect is further aggravated by addition of ethanol to the incubation medium. Sodium dodecyl sulfate-gel electrophoresis of mitochondria fractionated with acetic acid-lubrol, which were incubated in the presence of ethanol or acetaldehyde, revealed a modest over-all decrease in labeling. However, a polypeptide fraction in the molecular weight range of 36,000 to 40,000 was conspicuously decreased. This range includes subunits of cytochrome oxidase, cytochrome b, and ATPase. Liver mitochondria from rats fed ethanol chronically showed a comparable decrease in the 36,000- to 40,000-molecular weight peak after incubation with radioactive leucine in vitro and fractionation with acetic acid-lubrol. Similar results were obtained when mitochondrial protein synthesis was determined in vivo in chronically treated rats. The data suggest that chronic ethanol consumption interferes with mitochondrial membrane biogenesis and that several products are more sensitive to this effect than others.
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PMID:The effects of ethanol and acetaldehyde on the products of protein synthesis by liver mitochondria. 50 71

Permeabilized endothelial cell monolayers retracted on exposure to ATP and Ca2+. ADP, inosine triphosphate (ITP), GTP, adenosine 5'-(gamma-thio)triphosphate (ATP-gamma S), and 5'-adenylylimidodiphosphate failed to support retraction. However, ATP gamma S, a substrate for myosin light-chain kinase (MLCK) but not myosin adenosinetriphosphatase (ATPase), combined with ITP, a substrate for myosin ATPase but not MLCK, supported retraction. Two MLCK pseudosubstrate peptides, M5 and SM-1, inhibited endothelial cell retraction equally and more effectively than myosin kinase-inhibitory peptide with a sequence based on the phosphorylated site of myosin light chain. M5 was shown to inhibit thiophosphorylation of endothelial cell myosin light chains. Endothelial cells incubated with exogenous unregulated kinase in the presence of ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetra-acetic acid retracted on addition of ATP. This retraction was accompanied by thiophosphorylation of the 19 kDa myosin light chains in the presence of ATP gamma 35S. The N-ethylmaleimide-modified subfragment 1 of myosin heads, a specific inhibitor of actin-myosin interaction, prevented retraction. These data add support to the proposal of a central role for MLCK activation of myosin in endothelial retraction.
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PMID:Regulation of permeabilized endothelial cell retraction by myosin phosphorylation. 185 58

A continuous-flow method was developed for determining the stoichiometry of the gastric proton pump H,K-ATPase (EC 3.6.1.36) in its hydrolysis of ATP and translocation of H+ and the K+ congener 86Rb+. H,K-ATPase-containing vesicles which had been isolated from pig gastric mucosa were incubated at 37 degrees C for 2 h in 150 mM 86RbCl, 0.5 mM ethylenebis(oxyethylenenitrilo)tetra-acetic acid and 3 mM 2-(N-morpholino)ethane sulphonic acid (Mes) adjusted to pH 6.1 with Tris, and then applied onto a 0.45 micron pore size cellulose acetate filter. The immobilized vesicles were superfused with 0.15 mM Mes/Tris buffer, pH 6.1, containing 150 mM choline chloride and 0.2 mM MgCl2. After changing to a medium containing 0.1 mM ATP, the amounts and rates of H+ uptake, 86Rb+ efflux and ATP hydrolysis were measured. The initial ratio of Rb+ transported to ATP hydrolysed gave values of 0.96 +/- 0.26 (mean +/- SD, n = 28). The initial ratio of ATP-dependent Rb+ efflux to H+ uptake gave values of 0.92 +/- 0.28 (mean +/- SD, n = 28). The Mg-ATPase activity was measured in vesicles which had been incubated with choline chloride instead of RbCl. This activity was 15.8 +/- 8.7% (mean +/- SD) of the total ATPase activity in the initial fractions used for calculation of the stoichiometry. It is argued that this Mg-ATPase may be an intrinsic activity of the H,K-ATPase and that the relation between these activities is dependent on the amount of K+ (or Rb+) present in the assay.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:A continuous-flow technique for analysis of stoichiometry and transport kinetics of gastric H,K-ATPase. 196 37

A direct comparison of the ulcer-healing effects of two H(+)-K(+)-ATPase inhibitors (pantoprazole and omeprazole), one M1 antimuscarinic (telenzepine) and one H2 receptor antagonist (cimetidine) was performed in the rat. Gastric and duodenal ulcers were induced by local application of acetic acid and thereafter treated over 10 days by the test drugs. Overall and on a molar basis, ulcer healing was comparably accelerated by pantoprazole, omeprazole and telenzepine and less so by cimetidine. The same rank order was found with respect to the inhibition of gastric acid secretion in the modified Shay rat.
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PMID:Direct comparison between the ulcer-healing effects of two H(+)-K(+)-ATPase inhibitors, one M1-selective antimuscarinic and one H2 receptor antagonist in the rat. 198 99


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