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)

Arachidonic acid is released rapidly from cellular membrane phospholipids after pathological insults associated with the delayed development of brain edema. Intracerebral injection of arachidonic acid caused significant increases in brain water and sodium content with decreases in potassium content and Na+,K+-ATPase activity. The 125I-labeled bovine serum albumin spaces in brain (a measure of blood-brain barrier permeability) rose threefold 24 h after arachidonic acid injection. There was gross and microscopic evidence of edema. Saturated fatty acids and monounsaturated fatty acids were not effective. These data indicate that the endothelial cells of the blood-brain barrier are target sites for the action of arachidonic acid. It is hypothesized that the increased permeability of endothelial cells to macromolecules and water results from alterations of membrane phospholipids and increased vesicular transport, changes that are responsible for the delayed development of vasogenic edema.
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PMID:The role of arachidonic acid in vasogenic brain edema. 642 Jan 96

Hexachlorophene (HCP) has been found to dramatically affect erythrocyte membrane ATPase activity. The Na+,K+,Mg2+-ATPase of erythrocyte membranes was strongly inhibited by HCP. The Mg2+-ATPase was stimulated at lower concentrations of HCP, while at higher concentrations of HCP the activity decreased toward control levels. Inclusion of bovine serum albumin in the incubation medium protected each enzyme from the effect of HCP. A possible mechanism for the alteration of erythrocyte membrane ATPase activity by HCP is presented.
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PMID:Hexachlorophene-induced changes in erythrocyte membrane ATPase activity. 645 71

Attachment values of Mycoplasma pneumoniae to glass are normally very low when tested in buffer containing bovine serum albumin (10 mg/ml). However, the addition of one of the metabolizable sugars glucose, fructose, or mannose increased attachment more than 10-fold. The effect was dose dependent with a distinct optimum at about 0.25 mg/ml. Higher concentrations reduced this effect. Not only the sugars themselves but also the products of their catabolism, pyruvate and phosphoenolpyruvate, enhanced attachment. Pyruvate was effective in the same range of concentrations as the sugars, whereas phosphoenolpyruvate enhanced attachment at a significantly lower concentration (0.001 mg/ml). Higher levels of these substances also resulted in a decrease of attachment. The glucose-induced increase could be partially inhibited by glucose analogs, especially by 3-O-methyl-glucopyranoside, and by various inhibitors or glycolysis. Furthermore, attachment was strongly reduced by the uncoupling agents carbonylcyanide m-chlorophenylhydrazone and 2,4-dinitrophenol, as well as by dicyclohexylcarbodiimide, an inhibitor of the membrane-bound Mg2+-adenosine triphosphatase, whereas the ionophore valinomycin increased attachment by about 30%. These findings provide strong evidence for coupling between the attachment process of M. pneumoniae to glass and the utilization of metabolic energy.
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PMID:Role of energy metabolism in Mycoplasma pneumoniae attachment to glass surfaces. 678 36

Significant intracellular potassium depletion was documented in 57 patients with Crohn's disease by measurements of total body potassium, body water compartments, and red cell Na,K-ATPase units. Total body potassium deficits paralleled the activity of illness, but were not correlated to serum potassium levels. Treatment before surgery to improve individual body potassium content resulted in a reduced surgical mortality and complication rate compared with a retrospective series of 56 patients in whom pretreatment had simply been aimed at normalizing serum albumin and other standard serum parameters. In conclusion, preoperative nutritional support in Crohn's disease is recommended for patients with a total body potassium level less than 70% of normal. If whole body counting for direct measurement of total body potassium is not available, a Crohn's Disease Activity Index above 225 is proposed as the deciding level, and the parenteral administration of a standardized regimen consisting of 150 to 200 mval potassium plus 2500 to 3000 kcal daily for a two-week period is recommended.
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PMID:Total body potassium depletion and the need for preoperative nutritional support in Chrohn's disease. 681 56

Renin release was measured in the isolated rat kidney perfused with a recirculating artificial medium containing bovine serum albumin at 6.7 g per 100 ml of 11 g per 100 ml. At the higher concentration of albumin, glomerular filtration ceased and the rate of renin release over 70 minutes of perfusion was increased 6-fold. The addition of ouabain to the perfusate containing 11 g per 100 ml inhibited the release of renin, suggesting that inhibition of Na-K-ATPase or the related changes in cellular volume or composition prevented renin release. Lowering the osmolality of the perfusate by reducing the concentration of sodium chloride also prevented the increase in renin secretion produced by perfusion with 11 g per 100 ml albumin. Increasing the osmolality of the perfusate with mannitol restored the augmented renin release. These results are consistent with the hypothesis that alterations in the volume of certain cells, perhaps in the juxtaglomerular apparatus itself, can control renin release.
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PMID:Stimulation of renin release by hyperoncotic perfusion of the isolated rat kidney. 703 19

Male rats developed fatty liver after being fed on an ethanol-containing diet for 31 days. Liver mitochondria from these animals catalysed ATP synthesis at a slower rate when compared with mitochondria from pair-fed control rats (control mitochondria), and demonstrated lowered respiratory control with succinate as substrate, owing to a decrease in the State-3 respiratory rate. Respiration in the presence of uncoupler was comparable in mitochondria from both groups of rats. Translocation of both ATP and ADP was decreased in mitochondria from ethanol-fed rats, with ADP uptake being lowered more dramatically by ethanol feeding. Parameters influencing adenine nucleotide translocation were investigated in mitochondria from ethanol-fed rats. Experiments performed suggested that lowered adenine nucleotide translocation in these mitochondria is not the result of inhibition of the translocase by either long-chain acyl-CoA derivatives or unesterified fatty acids. Analysis of endogenous adenine nucleotides in these mitochondria revealed lowered ATP concentrations, but no decrease in total adenine nucleotides. In experiments where the endogenous ATP in these mitochondria was shifted to higher concentrations by incubation with oxidizable substrates or defatted bovine serum albumin, the rate of ADP translocation was increased, with a linear correlation being observed between endogenous ATP concentrations and the rate of ADP translocation. The depressed ATP concentration in mitochondria from ethanol-fed rats suggests that the ATP synthetase complex is replenishing endogenous ATP at a slower rate. The lowered ATPase activity of the ATP synthetase observed in submitochondrial particles from ethanol-fed animals suggests a decrease in the function of the synthetase complex. A decrease in the rate of ATP synthesis in mitochondria from ethanol-fed rats is sufficient to explain the decreased ADP translocation and State-3 respiration.
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PMID:Control of adenine nucleotide metabolism in hepatic mitochondria from rats with ethanol-induced fatty liver. 709 25

In Drosophila ovarian follicles, communication via gap junctions can be observed between the oocyte and its surrounding follicular epithelium. In the present study, the intercellular exchange of the fluorescent tracer Lucifer Yellow was analysed following pressure-injections of five different sera or protein solutions into the oocyte of stage-10 follicles. Three of the tested sera are directed against a channel-forming 16 kDa protein, which is a component of the vacuolar H(+)-ATPase and of Nephrops norvegicus gap junctions. When one of these antisera was injected 5-10 min prior to the dye, the percentage of follicles showing dye-coupling between oocyte and follicle cells was extremely small. On the other hand, injections of non-immune serum or of bovine serum albumin solution had only minor inhibitory effects. With indirect immunofluorescence, the three Nephrops antisera revealed a discrete punctate pattern at the membranes between neighbouring follicle cells as well as between follicle cells and oocyte. Most likely, this fluorescent pattern represents the distribution of gap junctions in the follicular epithelium. On immunoblots, the Nephrops antisera recognized a 29 kDa Drosophila ovary protein with high specificity. Affinity purification of one of these antisera against the 29 kDa protein revealed that this protein of Drosophila and the 16 kDa membrane-channel protein of Nephrops are immunologically related. Thus, the Nephrops antisera might help to reveal, in future injection experiments, the functional role of gap-junction mediated communication in Drosophila.
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PMID:Antisera against a channel-forming 16 kDa protein inhibit dye-coupling and bind to cell membranes in Drosophila ovarian follicles. 769 43

Helicobacter pylori and the fatty acids produced by this organism were compared for their acid inhibitory activity in isolated parietal cells and their interaction with gastric H+/K(+)-ATPase. H pylori (intact organisms, sonicates, methanolic extracts, and extracts from culture medium) and the fatty acids cis 9,10-methyleneoctadecanoic acid and tetradecanoic acid inhibited at fairly high concentrations histamine- and dibutyryl cyclic adenosine monophosphate stimulated acid production in isolated parietal cells, dissipated (with a slow onset) the H+/K(+)-ATPase created H+ gradient in gastric membrane vesicles, and inhibited H+/K(+)-ATPase activity in a concentration dependent manner. The inhibitory potency of H pylori and the fatty acids in relation to H+/K(+)-ATPase depended on the amount of membrane protein. Bovine serum albumin prevented enzyme inhibition and proton dissipation from gastric vesicles. The data indicate that H pylori establishes its antisecretory action in parietal cells by blocking H+/K(+)-ATPase activity and also by a detergent action at the apical parietal cell membrane. The fatty acids cis 9,10-methyleneoctadecanoic acid and tetradecanoic acid are probably the acid inhibitory factors secreted by H pylori.
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PMID:Interaction of Helicobacter pylori and its fatty acids with parietal cells and gastric H+/K(+)-ATPase. 795 21

Some kinetic parameters of the human red cell Ca(2+)-ATPase were studied on calmodulin-free membrane fragments following preincubation at 37 degrees C. After 30 min treatment with EGTA (1 mM) plus dithioerythritol (1 mM), a Vmax of about 0.4 mumol Pi/mg x hr and a Ks of 0.3 microM Ca2+ were found. When Mg2+ (10 mM) or Ca2+ (10 microM) were also added during preincubation, Vmax, but not Ks was altered. Ca2+ was more effective than Mg2+, thus increasing Vmax to about 1.3 mumol P/mg x hr. The presence of both Ca2+ and Mg2+ during pretreatment decreased Ks to 0.15 microM, while having no apparent effect on Vmax. Conversely, addition of ATP (2 mM) with either Ca2+ or Ca2+ plus Mg2+ increased Vmax without affecting Ks. Preincubation with Ca2+ for periods longer than 30 min further increased Vmax and reduced Ks to levels as low as found with calmodulin treatment. The Ca2+ activation was not prevented by adding proteinase inhibitors (iodoacetamide, 10 mM; leupeptin, 200 microM; pepstatin A, 100 microM; phenylmethanesulfonyl fluoride, 100 microM). The electrophoretic pattern of membranes preincubated with or without Mg2+, Ca2+ or Ca2+ plus Mg2+ did not differ significantly from each other. Moreover, immunodetection of Ca(2+)-ATPase by means of polyclonal antibodies revealed no mobility change after the various treatments. The above stimulation was not altered by neomycin (200 microM), washing with EGTA (5 mM) or by both incubating and washing with delipidized serum albumin (1 mg/ml), or omitting dithioerythritol from the preincubation medium.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Activation of the human red cell calcium ATPase by calcium pretreatment. 818 35

Protein degradation in Escherichia coli involves the ATP-dependent serine protease La. Protease La is a homotetramer with one proteolytic and one ATP binding site per monomer. Its proteolytic activity has been shown to be highly increased by simultaneous hydrolysis of ATP, which is essential for the degradation of protein substrates by this enzyme. We have cloned and purified a proteolytically inactive La mutant, in which the catalytically active serine residue at position 679 was replaced by alanine. Fluorescence and circular dichroism spectra of the purified wild type and mutant enzyme revealed identical conformations of the proteins. Based on this observation, the catalytic properties of the wild type enzyme and the S679A mutant were compared. Although the S679A mutant lacks proteolytic activity toward both peptide and protein substrates under all conditions investigated, its ATPase activity is completely unaffected by the removal of the protease activity. Since protein substrates stimulate the ATP-dependent hydrolysis of peptides by protease La, it has been argued that this stimulation is due to interactions with a regulatory binding site on the enzyme. In accordance with this model, protein substrates such as alpha-casein and denatured bovine serum albumin stimulate the ATPase activity of the S679A mutant to the same degree as in the active protease. Therefore, the intrinsic ATPase activity of protease La as well as its stimulation is not dependent on the simultaneous hydrolysis of the protein substrate.
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PMID:ATP hydrolysis is not stoichiometrically linked with proteolysis in the ATP-dependent protease La from Escherichia coli. 822 58


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