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 ouabain-sensitive and the ethacrynic acid-sensitive sodium efflux from erythrocytes of patients with cystic fibrosis are both decreased. Furthermore, the ouabain-sensitive adenosine triphosphatase activity is diminished in the red blood cell ghosts of these patients. Perhaps of greater significance is the fact that ethacrynic acid-sensitive sodium efflux is clearly diminished in the erythrocytes of the asymptomatic parents of these sick children. This defect in sodium transport may be valuable for detecting the heterozygous carrier state.
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PMID:Red-cell transport defect in patients with cystic fibrosis and in their parents. 423 15

The activity of Ca-ATPase (Ca2+,Mg2+-ATPase, ATP phosphohydrolase, EC 3.6.1.3) was measured in erythrocyte membrane preparations from 37 cystic fibrosis patients, 27 with pancreatic insufficiency and 10 with pancreatic sufficiency, and from 24 healthy controls. The mean maximal calcium-stimulated specific activities, in the absence and presence of purified calmodulin, of the pancreatic sufficient patients (34.3 +/- 4.2 and 75.9 +/- 6.9 nmol/min/mg) was indistinguishable from that of controls (35.8 +/- 2.6 and 84.3 +/- 4.7 nmol/min/mg), while both activities of patients with pancreatic insufficiency were significantly decreased (28.9 +/- 1.3, p less than 0.02; 65.2 +/- 3.0, p less than 0.001) compared to the control group. Similarly, the mean erythrocyte membrane (Na + K)ATPase activity was decreased only for those patients with a history of steatorrhea and who clinically required pancreatic enzyme therapy and had low immunoreactive trypsin levels (10.6 +/- 0.8 versus control, 13.4 +/- 1.1, and pancreatic sufficient patients, 13.3 +/- 1.4 nmol/min/mg; p less than 0.025). No correlation was found between any of the ATPase activities and the clinical scores of the patients, suggesting the lack of significant contribution of general clinical status to the activities of those cation transporters.
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PMID:Calcium-ATPase activity in cystic fibrosis erythrocyte membranes: decreased activity in patients with pancreatic insufficiency. 609 Oct 22

Ejaculates from two men with cystic fibrosis (CF) were examined. Both had azoospermia. A considerable decrease in volume and fructose content was noted. The absolute amounts of calcium, magnesium, and zinc per ejaculate showed normal values in one of the patients but were two to three times increased the the other compared to mean values of a control group. Thus the concentrations of these cations were increased at least fivefold in both patients. The amount of Mg(2+)-and Ca(+)-dependent ATPase was comparable to that of controls, but values were higher than in men with oligospermia. Both the divalent cations and the Mg2+- and Ca2+-dependent ATPase curve profiles of split ejaculate fractions were atypical. Secretory granules and vesicles were plentiful in the seminal plasma of both patients while amorphous substance was practically absent. The present findings agree with a less affected function of the prostate gland and a dysfunction of the seminal vesicles in these patients.
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PMID:Analysis of ejaculates from patients with cystic fibrosis. 611 25

Nasal mucosa biopsies were taken from a child with Kartagener's syndrome. The biopsies were prepared for light and electron microscopic examination. Unfixed cryocut sections were stained with the magnesium-activated ATPase reaction. There was a partial loss of the dynein arms within the cilia. Many compound cilia were present and, sometimes, defects of the mitochondria of the lining epithelial cells as well as the glandular cells were observed. Histochemically the ATPase reaction was at first completely negative and sometime later it was greatly reduced within the lining and the glandular epithelial cells, especially in the apical border. Biopsies from children with cystic fibrosis and allergic rhinitis served as controls.
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PMID:[Diagnosis and pathogenetic aspects of the Kartagener syndrome based on nasal mucosa biopsies]. 621 69

In the present study, we compared the kinetics of activation by Na, of red cell membrane Ca-ATPase of cystic fibrosis (CF) patients and healthy volunteers (controls). Calmodulin (membrane-free hemolysate) was included in the assay medium to promote maximal Ca-ATPase activation. There were no significant differences between the red cell Ca-ATpase activities of the two groups, assayed either in the absence or in the presence of optimal concentrations of Na. There were also no significant differences between the apparent dissociation constants or Hill coefficients for activation of red cell Ca-ATPase by Na. On the other hand, the percent activation by Na of red cell Ca-ATPase activity of the CF patients was approximately 40% greater than that of the controls. The additional increment of Ca-ATPase activity due to the elevated percent activation was about 14% of the total red cell Ca-ATPase activity of the CF patients. Although this increment of Ca-ATPase activity is relatively small, the increased percent activation by Na does suggest an alteration in the enzyme's response to Na. At present we do not know whether or not this alteration applies to Ca-transport or if it is of any pathophysiological importance.
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PMID:Red cell membrane Ca-ATPase in cystic fibrosis: increased activation by Na. 623 48

Plasma membrane enriched preparations obtained from cultured human skin fibroblasts by differential centrifugation and sucrose density centrifugation techniques were found to contain a Mg2+-dependent Ca2+-stimulated ATPase activity. The specific activity of the (Mg2+ + Ca2+)-ATPase present was 4-5-fold higher than that present in crude membrane preparations and 80-100-fold higher than that present in homogenates. The (Mg2+ + Ca2+)-ATPase activity of both crude and plasma membrane enriched preparations of cultured fibroblasts from cystic fibrosis patients was significantly reduced compared to that activity observed in age-matched controls. This study corroborates our previous observations made in crude homogenate preparations of fibroblasts and indicates another cell type where (Mg2+ + Ca2+)-ATPase activity may be altered in cystic fibrosis.
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PMID:(Mg2+ + Ca2+)-ATPase activity in plasma membrane enriched preparations of human skin fibroblasts: decreased activity in fibroblasts derived from cystic fibrosis patients. 644 74

Erythrocyte membranes were prepared by a method which should ensure binding of an activator protein (calmodulin) to the calcium dependent membrane ATPase involved in calcium transport. The level of enzyme activity, assayed at optimum conditions, was 5-400 times higher than that found in previous investigations on cystic fibrosis patients. The Ca2+-ATPase activity of the cystic fibrosis patients was reduced by 15% compared to control subjects, whereas patients suffering from chronic pulmonary diseases did not deviate from controls. Even if a reduction of Ca2+ pumping activity occurs in other cells, a 15% decrease could hardly be the only cause of the changed calcium concentrations in secretions from cystic fibrosis patients.
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PMID:Activator-associated Ca2+-ATPase in erythrocyte membranes from cystic fibrosis patients. 644 22

1. Airway epithelium in cystic fibrosis is characterized by a defect in chloride secretion across the apical membrane and an increase in sodium absorption. The increased rate of sodium absorption can be inhibited in vitro by ouabain, a Na(+)-K(+)-ATPase inhibitor, and in cystic fibrosis patients the number and activity of nasal epithelial Na(+)-K(+)-ATPase pumps is increased. 2. We have performed a series of studies to determine whether drugs which modify airway epithelial Na(+)-K(+)-ATPase activity in vitro can modify nasal potential in cystic fibrosis patients in vivo. As transepithelial nasal potential difference measurements were used to study the effect of drug modulation of airway epithelial ion transport in vivo, the repeatability of the technique was first evaluated. In order to assess the effectiveness of the technique used for measuring nasal potential difference, a pilot study was carried out using topical amiloride, a drug which has previously been shown to inhibit airway epithelium sodium transport in vivo. We then studied the effects of ouabain and digoxin, two inhibitors of Na(+)-K(+)-ATPase, on nasal potential difference. 3. In study 1, nasal potential difference measurements were repeated on non-consecutive days in 20 patients with cystic fibrosis and 20 healthy individuals. Healthy subjects had a mean (SEM) potential difference value of -19.5 (0.9) mV with a 95% range for a single estimate of 75-133%. In patients with cystic fibrosis, the mean (SEM) potential difference was -40.4, (2.1) mV, with a 95% range for a single estimate of 74-136%.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effect of oral digoxin, topical ouabain and salbutamol on transepithelial nasal potential difference in patients with cystic fibrosis. 749 24

Transepithelial Cl- secretion in vertebrates is accomplished by a secondary active transport process brought about by the coordinated activity of apical and basolateral transport proteins. The principal basolateral components are the Na+/K(+)-ATPase pump, the Na+/K+/2Cl- cotransporter (symporter) and a K+ channel. The rate-limiting apical component is a cyclic-AMP-stimulated Cl- channel. As postulated nearly two decades ago, the net Cl- movement from the blood to the lumen involves entry into the epithelial cells with Na+ and K+, followed by active Na+ extrusion via the pump and passive K+ exit via a channel. Intracellular [Cl-] is raised above electrochemical equilibrium and exits into the lumen when the apical Cl- channel opens. Cl- secretion is accompanied by a passive paracellular flow of Na+. The tubules of the rectal glands of elasmobranchs are highly specialized for secreting concentrated NaCl by this mechanism and hence have served as an excellent experimental model in which to characterize the individual steps by electrophysiological and ion flux measurements. The recent molecular cloning and heterologous expression of the apical Cl- channel and basolateral cotransporter have enabled more detailed analyses of the mechanisms and their regulation. Not surprisingly, since hormones acting through kinases control secretion, both the Cl- channel, which is the shark counterpart of the CFTR (Cystic Fibrosis Transmembrane Conductance Regulator), and the cotransporter are regulated by phosphorylation and dephosphorylation. The primary stimulation of secretion by hormones employing cyclic AMP as second messenger activates CFTR via the direct action of protein kinase A (PKA), which phosphorylates multiple sites on the R domain. In contrast, phosphorylation of the cotransporter by as yet unidentified kinases is apparently secondary to the decrease in intracellular chloride concentration caused by anion exit through CFTR.
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PMID:The molecular basis of chloride transport in shark rectal gland. 752 18

Cystic fibrosis is caused by mutations in the cell membrane protein called CFTR (cystic fibrosis transmembrane conductance regulator) which functions as a regulated Cl- channel. Although it is known that CFTR contains two nucleotide domains, both of which exhibit the capacity to bind ATP, it has not been demonstrated directly whether one or both domains can function as an active ATPase. To address this question, we have studied the first CFTR nucleotide binding fold (NBF1) in fusion with the maltose-binding protein (MBP), which both stabilizes NBF1 and enhances its solubility. Three different ATPase assays conducted on MBP-NBF1 clearly demonstrate its capacity to catalyze the hydrolysis of ATP. Significantly, the mutations K464H and K464L in the Walker A consensus motif of NBF1 markedly impair its catalytic capacity. MBP alone exhibits no ATPase activity and MBP-NBF1 fails to catalyze the release of phosphate from AMP or ADP. The Vmax of ATP hydrolysis (approximately 30 nmol/min/mg of protein) is significant and is markedly inhibited by azide and by the ATP analogs 2'-(3')-O-(2,4,6-trinitrophenyl)-adenosine-5'-triphosphate and adenosine 5'-(beta, gamma-imido)triphosphate. As inherited mutations within NBF1 account for most cases of cystic fibrosis, results reported here are fundamental to our understanding of the molecular basis of the disease.
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PMID:The first nucleotide binding fold of the cystic fibrosis transmembrane conductance regulator can function as an active ATPase. 754 72


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