Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P20020 (adenosine triphosphatase)
 3,299 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In an effort to determine the subcellular localization of sodium- and potassium-activated adenosine triphosphatase (Na(+), K(+)-ATPase) in the pseudobranch of the pinfish Lagodon rhomboides, this tissue was fractionated by differential centrifugation and the activities of several marker enzymes in the fractions were measured. Cytochrome c oxidase was found primarily in the mitochondrial-light mitochondrial (M+L) fraction. Phosphoglucomutase appeared almost exclusively in the soluble (S) fraction. Monoamine oxidase was concentrated in the nuclear (N) fraction, with a significant amount also in the microsomal (P) fraction but little in M+L or S. Na(+), K(+)-ATPase and ouabain insensitive Mg(2+)-ATPase were distributed in N, M+L, and P, the former having its highest specific activity in P and the latter in M+L. Rate sedimentation analysis of the M+L fraction indicated that cytochrome c oxidase and Mg(2+)-ATPase were associated with a rapidly sedimenting particle population (presumably mitochondria), while Na(+), K(+)-ATPase was found primarily in a slowly sedimenting component. At least 75% of the Na(+), K(+)-ATPase in M+L appeared to be associated with structures containing no Mg(2+)-ATPase. Kinetic properties of the two ATPases were studied in the P fraction and were typical of these enzymes in other tissues. Na(+), K(+)-ATPase activity was highly dependent on the ratio of Na(+) and K(+) concentrations but independent of absolute concentrations over at least a fourfold range.
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PMID:Localization of Na + , K + -ATPase and other enzymes in teleost pseudobranch. I. Biochemical characterization of subcellular fractions. 434 21

1. Induction of the formation of lipid peroxide in suspensions of liver microsomal preparations by incubation with ascorbate or NADPH, or by treatment with ionizing radiation, leads to a marked decrease of the activity of glucose 6-phosphatase. 2. The effect of peroxidation can be imitated by treating microsomal suspensions with detergents such as deoxycholate or with phospholipases. 3. The substrate, glucose 6-phosphate, protects the glucose 6-phosphatase activity of microsomal preparations against peroxidation or detergents. 4. The loss of glucose 6-phosphatase activity is not due to the formation of hydroperoxide or formation of malonaldehyde or other breakdown products of peroxidation, all of which are not toxic to the enzyme. 5. All experiments lead to the conclusion that the loss of activity of glucose 6-phosphatase resulting from peroxidation is a consequence of loss of membrane structure essential for the activity of the enzyme. 6. In addition to glucose 6-phosphatase, oxidative demethylation of aminopyrine or p-chloro-N-methylaniline, hydroxylation of aniline, NADPH oxidation and menadione-dependent NADPH oxidation are also strongly inhibited by peroxidation. However, another group of enzymes separated with the microsomal fraction, including NAD(+)/NADP(+) glycohydrolase, adenosine triphosphatase, esterase and NADH-cytochrome c reductase are not inactivated by peroxidation. This group is not readily inactivated by treatment with detergents. 7. Lipid peroxidation, by controlling membrane integrity, may exert a regulating effect on the oxidative metabolism and carbohydrate metabolism of the endoplasmic reticulum in vivo.
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PMID:Effects of lipid peroxidation on membrane-bound enzymes of the endoplasmic reticulum. 439 3

1. The values of the protein, RNA and phospholipid concentrations within the total microsomal fractions obtained from different stages of embryonic chick liver are compared. 2. Only the phospholipid content increases significantly with increasing developmental age. 3. The lack of membranes in the early stages of development and the relative constancy of RNA values during development suggests that some of the protein present at the early developmental stages is of a non-membranous non-ribosomal nature. 4. Glucose 6-phosphatase, adenosine triphosphatase, NADH(2)-cytochrome c reductase and diaphorase all increased in activity as development progressed. 5. Comparisons of submicrosomal fractions with respect to their protein, RNA and phospholipid content showed that in all embryonic stages fraction II (rough-membrane fraction) contained more than 60% of the proteins, RNA and phospholipid of the microsomal fraction. 6. Glucose 6-phosphatase was shown to be present predominantly in fraction II, whereas adenosine triphosphatase was present predominantly in fraction Iab (smooth-membrane fraction). 7. The significance of the differences between the smooth- and rough-microsomal fractions is discussed.
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PMID:Changes in the chemical composition and the enzymic activities of hepatic microsomes of the chick embryo during development. 604 89

The denatured catalytic polypeptide of mouse brain (Na+ + K+)-adenosine triphosphatase(ATPase) was separated from microsomal membranes on polyacrylamide gels and used as an immunogen. The antiserum, characterized by immunoblots, recognizes the polypeptide corresponding to the catalytic unit in various fractions of mouse brain and cross-reacts with the catalytic unit from lamb kidney, duck salt gland, and electroplax. The same polypeptide in brain and salt gland is recognized by antiserum raised against purified lamb kidney enzyme. Light microscopy was performed with the peroxidase-conjugated second antibody method. In mouse cerebellum, immunochemical staining outlines Purkinje cell and granule cell perikarya. Intense activity is associated with regions of high synaptic content including the pericellular basket meshes and preaxonal regions of Purkinje cells and the glomeruli in the granular layer. In the molecular layer, the neuropil is diffusely reactive with distinct vertically oriented processes evident. White matter exhibits light stain deposition. Choroid plexus presents abundant reaction product only at ependymal apical surfaces, while the ependymal lining of the fourth ventricle displays little or no immunoreactivity. Specificity of the antiserum was demonstrated further in mouse kidney where staining conforms to the well-characterized localization of the enzyme along basolateral surfaces of cortical and medullary tubules. The biochemical and immunocytochemical data show the efficacy of generating antisera to brain (Na+ + K+)-ATPase using catalytic polypeptide as an immunogen.
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PMID:Purification of mouse brain (Na+ + K+)-ATPase catalytic unit, characterization of antiserum, and immunocytochemical localization in cerebellum, choroid plexus, and kidney. 609 58

Polyadenylated RNA prepared from neonatal rat muscle was translated in a rabbit reticulocyte cell-free system. Two sarcoplasmic reticulum proteins, the Ca2+ + Mg2+-dependent adenosine triphosphatase (ATPase) and calsequestrin, were isolated from the translation mixture by immunoprecipitation, followed by electrophoresis in sodium dodecyl sulfate-polyacrylamide gels. The [35S]methionine-labeled translation products were characterized by molecular weight, peptide mapping, and NH2-terminal sequence analysis. The ATPase synthesized in the cell-free system was found to have the same molecular weight (Mr = 100,000) and [35S]-methionine-labeled peptide map as the mature ATPase. The methionine residue present at the NH2 terminus of the mature ATPase was donated by initiator methionyl-tRNArMet and it became acetylated during translation. These results suggest that the ATPase was synthesized without an NH2-terminal signal sequence. Calsequestrin (Mr - 63,000) was synthesized as a higher molecular weight precursor (Mr = 66,000) that contained an additional [35S]methionine-labeled peptide when compared to mature calsequestrin. The NH2-terminal sequence of the precursor was different from the mature protein. The precursor was processed to a polypeptide with a molecular weight identical with mature calsequestrin when microsomal membranes prepared from canine pancreas were included during translation. These results show that calsequestrin is synthesized with an NH2-terminal signal sequence that is removed during translation. These data add to the evidence that the ATPase and calsequestrin follow distinctly different biosynthetic pathways, even though, ultimately, they are both located in the same membrane.
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PMID:Assembly of the sarcoplasmic reticulum. Cell-free synthesis of te Ca2+ + Mg2+-adenosine triphosphatase and calsequestrin. 616 Jan 54

Effect of verapamil on the organic acid transport was examined with rat kidney cortical slices. Verapamil increased the initial rate of p-aminohippurate (PAH) uptake, markedly enhanced its maximal accumulation under steady-state conditions and depressed the efflux of PAH. The accumulation of urate was also stimulated by verapamil. D600, a derivative of verapamil, showed the same effect as verapamil with regard to the stimulation of PAH accumulation. Kinetic studies revealed that verapamil resulted in an increase in the Vmax of the transport of PAH. The apparent Km remained essentially constant. The PAH accumulation was enhanced by aerobic preincubation of the slices with verapamil at 37 degrees C. On the other hand, the preincubation of the slices with verapamil at 0 degrees C did not alter the PAH accumulation. Oxygen consumption and ATP content in the slices and microsomal (Na+ + K+)adenosine triphosphatase activity were not affected by verapamil. Verapamil enhanced a Na+ gradient to some degree. however, the PAH accumulation in the presence of verapamil and ouabain was increased approximately the same amount as in the absence of these drugs regardless of the dissipation of the Na+ gradient by ouabain. These results suggest that verapamil accumulated by the slices stimulates the PAH uptake and its stimulatory action cannot be explained by the increase in the Na+ gradient and stimulation of (Na+ + K+)adenosine triphosphatase activity.
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PMID:Stimulatory action of verapamil on transport of organic acids in rat kidney cortical slices. 621 70

Previous studies have identified a cellular energy deficit in gastric mucosa after ischemia. We studied the processes of energy generation (mitochondrial function) and energy utilization (microsomal adenosine triphosphatase [ATPase] activity) in an experimental model of stress. Rabbits were divided into four groups: I, fed controls (n = 7); II, 24-hour fasted controls (n = 7); III, fasted, anesthetized, and cannulated controls (n = 7); and IV, fasted, anesthetized, cannulated, and bled rabbits. Bleeding consisted of 25 ml blood/kg into a reservoir for 60 minutes; the blood was then reinfused. Animals were killed 30 minutes after reinfusion; antral, corpus, and fundus mucosae were dissected; each region of mucosa was homogenized; and mitochondrial and microsomal fractions were isolated by differential centrifugation. No animals in group I or II had gastric ulcerations. Three of seven animals in group III and all group IV animals had corpus and fundus ulcers. No antral ulcers were seen in any group. The respiratory control index (RCI) of antral mitochondria was increased in groups II, III, and IV but was unchanged in all groups of corpus and fundus mitochondria. Studies of microsomal ATPase activity indicated increased activity of potassium-stimulated ATPase in the corpus mucosa. In the corpus mucosa, total ATPase activity was increased primarily as a consequence of increased potassium-stimulated ATPase. These data indicate that increased RCI is associated with gastric mucosal integrity in the antrum. Accelerated utilization of available adenosine triphosphate by corpus membrane ATPases may further compromise energy homeostasis during stress.
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PMID:Bioenergy metabolism of gastric mucosa during stress. 621 53

Inhibition of adenosine triphosphatase (ATPase) by silver nitrate (AgNO3) in vitro was studied in microsomal fractions or tissue homogenates of canine brain and kidney, and human kidney. In microsomal fractions, AgNO3 was an indiscriminate inhibitor of ouabain-sensitive (Na+ + K+ ATPase) and ouabain-insensitive (Mg2+ ATPase) activities with 50% inhibition obtaining at concentrations on the order of 10(-7) to 10(-6)M. The enzyme was protected by cysteine. Changing the concentrations of Na+, K+, H+, Mg2+ and ATP did not alter the fractional inhibition of Na+ + K+ ATPase by a constant concentration of AgNO3. An aqueous suspension of silver sulfadiazine had an inhibitory potency similar to AgNO3. It was concluded that silver gives a different pattern of Na+ + K+ ATPase inhibition than other metallic inhibitors of the enzyme so far examined.
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PMID:Inhibition of adenosine triphosphatase in vitro by silver nitrate and silver sulfadiazine. 624 May 33

Inhibition of adenosine triphosphatase (ATPase) by chlorauric acid (Au3+) and gold sodium thiomalate (Au+) was studied in dog brain and kidney and in human kidney enzyme preparations. Au3+ indiscriminately affected ouabain-sensitive (Na+ + K+-dependent) ATPase and ouabain-insensitive (Mg2+-dependent) ATPase with concentrations for 50% inhibition (I50) approximately 10(-6) M. The I50 of Au3+ for Na+ + K+ ATPase was several-fold higher in homogenates than in microsomal fractions. The enzyme was protected by bovine serum albumin. Although Au3+ and Au+ were equipotent against Mg2+ ATPase, Au+ inhibited Na+ + K+ ATPase 2 to 3 times more effectively than did Au3+. The inhibitory action of Au3+ (but not Au+) was potentiated by ascorbic acid, suggesting reduction of Au3+ to Au+ by ascorbic acid. The fractional inhibition of Na+ + K+ ATPase by Au3+ or Au+ was not affected by changing concentrations of NaCl, KCl, MgCl2, ATP, and MgATP. Decreasing pH from 8.0 to 6.8 enhanced both Au+ and Au3+ inhibition. We conclude that gold is one of the most potent nonspecific of Na+ + K+ ATPase, with characteristics differing from other metallic inhibitors of this enzyme system.
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PMID:Inhibition of adenosine triphosphatases by gold. 624 62

Adriamycin ws tested as a possible inhibitor of cardiac sodium-potassium-activated adenosine triphosphatase (Na-K-ATPase). At concentrations of 10(-4) M and lower, Adriamycin had no effect upon either ouabain-sensitive (Na-K-ATPase) or ouabain-insensitive adenosine triphosphatase activity in homogenates and microsomal fractions of cardiac tissue from several different species. Adriamycin inhibited adenosine triphosphatase activity at a concentration of 10(-3) M, but this was due to the inhibition of ouabain-insensitive adenosine triphosphatase rather than to inhibition of Na-K-ATPase. Under no condition was an inhibition of Na-K-ATPase activity by Adriamycin observed. These conditions included preincubation of the enzyme with Adriamycin, chelation of Ca2+, addition of reduced nicotinamide adenine dinucleotide phosphate, and variation of buffer and pH. It was concluded that Na-K-ATPase is not a likely site of Adriamycin-induced cardiotoxicity.
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PMID:Cardiac sodium, potassium-adenosine triphosphatase as a possible site of adriamycin-induced cardiotoxicity. 625 69


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