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Query: UNIPROT:P20020 (adenosine triphosphatase)
 3,299 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The present studies concern the roles of synthesis and degradation of the large subunit of (Na+ + k+)-adenosine triphosphatase (NaK-ATPase) in the response to triiodothyronin (T3). Single doses of either the diluent of T3 (50 mug/100 g body weight) were given to two pairs of surgically thyroidectomized rats. Twenty hours after injection, the rats received 3H- or 35S-labeled methionine administered as a constant injusion into the tail vein for 1 h. The kidneys were removed either 8 h or 20 h after infusion and the eight kidneys were divided into pairs, as follows. I, 3H (diluent)/35S (T3); II, 35S (diluent)/3H (T3); III, 3H (diluent)/35S (diluent); IV, 3H (T3)/35S (T3). Partially purified NaK-ATPase was prepared from the pooled homogenates and prepared from the pooled homogenates and analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAG-electrophoresis). The large subunit of NaK-ATPase was identified by (Na+ + mg2+)-dependent and K+-sensitive incorpotation of 32P from [gamma-32P]ATP. This component had an estimated molecular weight of 92,000 and migrated as a single peptide in gels of varying total carylamide concentration, with respect to: (1) Coomassie blue staining, (b) (Na+ + Mg2+)-dependent, K+-sensitive incorporation of 32P from [gamma-32-P]ATP, and (c) T3-dependent enhanced incorporation of labeled methionine. T3 augmented incorporation of labeled methionine into the large subunit by 44% 8 h after infusion of the amino acid and by 61% 20 h after infusion. Incorporation of methionine into two adjacent polypeptides in the SDS gels was unaffected by thyroid status. The effect otical NaK-ATPase was assessed by a double label technique. Pairs of thyroidectomized rats were injected with either the diluent or 50 mug of T3/100 g body weight at 48-h after the first injection (diluent or T3, i.e. Day "zero"). Kidney cortices were processed on either Day 4 or Day 6; the partially purified NaK-ATPase fraction was prepared, labeled with [gamma-32P]ATP, and analyzed by SDS-PAG-electrophoresis. The degredation rate constants of the large subunit were similar; 0.145 and 0.124 day-1 for the hypothyroid and T3-treated groups, respectively. Thus, the T2-dependent increase in incorporation of labeled methionine into the large subunit appears to result from enhanced synthesis and this increase is sufficient to account for the entire increase in both the number of the activity of the NaK-ATPase units.
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PMID:Effect of triiodothyronine on the synthesis and degradation of renal cortical (Na+ + k+)-adenosine triphosphatase. 13 43

The portion of Escherichia coli adenosine triphosphatase (ATPase) which is peripheral to the membrane (ECFl) is composed of five separate polypeptides referred to as alpha, beta, gamma, delta, and epsilon. Treating purified ECFl with pyridine precipitated the three larger polypeptides (alpha, beta, and gamma), but the two smaller ones (delta and epsilon), which represent only about 10% of ECFl, remained in solution. After removing the pyridine, both delta and epsilon were active and both were obtained in essentially pure form after chromatography on a single molecular-seive column. epsilon strongly inhibited the ATPase activity of ECFl, indicating that epsilon has a regulatory role in the enzyme. epsilon inhibited ECFl missing delta, indicating that delta is not required for inhibition by epsilon. However, enzyme containing just the alpha and beta subunits, which was prepared by treating ECFl with a protease, was fully active hydrolytically but not at all sensitive to inhibition by epsilon. This result suggests that the gamma polypeptide is required for the inhibition of the ATPase by epsilon. delta restored the capacity of ECFl missing delta to recombine with ECFl-depleted membrane vesicles. The ECFl, which became attached to the vesicles by the added delta, was functional in energy transduction, as evidenced by the coupling of ATP hydrolysis to the transhydrogenase reaction in the vesicles. The rebinding of ECFl missing delta was directly proportional to the amount of delta added until all the ECFl receptors in the membranes were occupied. delta may be a stalk which connects the Fl headpiece to the membrane, since the attachment of ECFl to the membrane exhibited an absolute dependence on delta. Although delta is known to have an apparent molecular weight of about 20,000 by gel electrophoresis in the presence of sodium dodecyl sulfate, the active delta eluted from a molecular-seive column with an apparent molecular weight of about 35,000, suggesting that in the active form delta is a dimer or rather elongated in shape. The active epsilon subunit eluted from the same column with an apparent molecular weight of about 16,000.
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PMID:Purification of membrane attachment and inhibitory subunits of the proton translocating adenosine triphosphatase from Escherichia coli. 13 33

Coated vesicles from the brain have been purified to near morphological homogeneity by a modification of the method of Pearse. These vesicles resemble sarcoplasmic reticulum fragments isolated from skeletal muscle. They contain proteins with 100,000- and 55,000-dalton mol wt which co-migrate on polyacrylamide gels, in the presence of sodium dodecyl sulfate, with the two major proteins of the sarcoplasmic reticulum fragment. These vesicles contain adenosine triphosphatase (ATPase) activity which is stimulated by calcium ions in the presence of Triton X-100 (Rohm & Haas Co., Philadelphia, Pa.), displaying maximal activity at 8 x 10(-7) M Ca ++. They take up calcium ions from the medium, and this uptake is stimulated by ATP and by potassium oxalate, a calcium-trapping agent. The 100,000-dalton protein of the coated vesicles displays immunological reactivity with an antiserum directed against the 100,000-dalton, calcium-stimulated ATPase of the sarcoplasmic reticulum. As with the sarcoplasmic reticulum fragment, this protein becomes radiolabeled when coated vesicles are briefly incubated with gamma-labeled [32P]ATP. The possible functions of coated vesicles as calcium-sequestering organelles are discussed.
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PMID:Evidence that coated vesicles isolated from brain are calcium-sequestering organelles resembling sarcoplasmic reticulum. 14 39

A microsomal fraction from canine brain gray matter has been extracted with the detergent sodium dodecyl sulfate to partially purify the membrane-bound (Na+ + K+)-stimulated adenosine triphosphatase. Phospholipid, glycolipid, and a family of other glycoproteins are also enriched by the procedure; it is proposed that the product is an intrinsic membrane protein fraction. 6--8-fold purification of (Na+ + K+)-ATPase is obtained without solubilizing the enzyme and without irreversibly altering its turnover number. Final specific activities are 350--400 mumol of ATP hydrolyzed/h per mg protein. The stimulation and reversible inactivation of the (Na+ + K+)-ATPase by dodecyl sulfate were examined for information relevant to the mechanism of action of the detergent.
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PMID:Purification from brain of an intrinsic membrane protein fraction enriched in (Na+ + K+)-ATPase. 14 8

Synthesis of total cellular proteins of Escherichia coli was studied upon transfer of a log-phase culture from 30 (or 37) to 42 degrees C. Cells were pulse-labeled with [3H]leucine, and the labeled proteins were analyzed by gel electrophoresis in the presence of sodium dodecyl sulfate. The rates of synthesis of at least five protein chains were found to increase markedly (5- to 10-fold) within 5 min after temperature shift-up and gradually decrease to the new steady-state levels, in contrast to the majority of proteins which gradually increase to the steady-state levels (about 1.5-fold the rate at 30 degrees C). Temperature shift-down did not cause any appreciable changes in the pattern of protein synthesis as detected by the present method. Among the proteins greatly affected by the temperature shift-up were those with apparent molecular weights fo 87,000 (87K), 76K, 73K, 64K, and 61K. Two of them (64K and 61K) were found to be precipitated with specific antiserum against proteins that had previously been shown to have an adenosine triphosphatase activity. The bearings of these findings on bacterial adaptation to variation in growth temperature are discussed.
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PMID:Transient regulation of protein synthesis in Escherichia coli upon shift-up of growth temperature. 14 9

The oligomycin- and N,N'-dicyclohexylcarbodiimide-sensitive adenosine triphosphatase complex extracted with Triton X-100 from the chromatophores of Rhodospirillum rubrum was extensively purified. The purification procedure included (diethylamino)ethylcellulose chromatography and glycerol gradient centrifugation. The specific activity of Mg2+-dependent ATP hydrolysis in the purified preparation increased about 11-fold, while that of Ca2+-dependent ATP hydrolysis increased 50-fold as compared with chromatophores. The purified adenosine triphosphatase complex dissociated into a maximum of eight different polypeptides upon electrophoresis in the presence of sodium dodecyl sulfate. The estimated subunit molecular weights were as follows: 56 000 (alpha), 50 000 (beta), 33 000 (gamma), and those ranging from 17 000 to 9400 for the remaining smaller subunits. The purified preparation was incorporated into phospholipid vesicles by using the freeze--thaw technique. The reconstituted vesicles catalyzed [32P]ATP exchange, which was almost completely inhibited by both oligomycin and N,N'-dicyclohexylcarbodiimide as well as by a protonophorous uncoupler, carbonyl cyanide p-(trifluoromethoxy)phenylhydrazone.
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PMID:Purification of the energy-transducing adenosine triphosphatase complex from Rhodospirillum rubrum. 15 74

To investigate the dystrophic influence on the characteristics of actin, a method for the isolation of F-actin filaments from the skeletal muscle of small sizes, i.e., less than 0.5 g, was devised. In this method, minced muscle was treated with collagenase and hyaluronidase, and the isolated filaments were washed with adenosine triphosphate (ATP). Upon examination in the sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the ATP-washed filaments showed a protein component identical in mobility to actin in untreated myofibrils or to that prepared by the conventional method. Electron microscopic appearances of the filaments were similar to those of F-actin filaments described in the literature. The dimensions of the filaments were 0.5--2.5 micrometer in length and 60--70 A in diameter. The ability to activate the Mg-adenosine triphosphatase or myosin was found to be Ca2+ independent. In all aspects of the above characteristics, the filaments from leg muscles of 129/Re dydy dystrophic mice and their litter mates were observed to be identical.
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PMID:Isolation of F-actin filaments. Comparison of F-actin filament preparations from normal and dystrophic mouse muscle. 15 92

Triton X-100-insoluble residues from Micrococcus lysodeikticus membranes were analyzed by crossed immunoelectrophoresis after dispersal of the residues in sodium dodecyl sulfate (SDS). Conditions which produce no obvious distortion of the immunoprecipitate profile and which allow qualitative and quantitative analyses of the antigens present in the extracts are described. Two main antigens were detected; these were identified as succinate dehydrogenase (EC 1.3.99.1) and adenosine triphosphatase (EC 3.6.1.3). As determined by peak area estimations, the maximal release of succinate dehydrogenase and of adenosine triphosphatase from Triton X-100-insoluble membrane residues occurred at protein/SDS ratios of about 4.3:1 (0.2% SDS) and 6.8:1 (0.13% SDS), respectively. A comparison of enzyme activities of SDS extracts with those of untreated, control Triton X-100-insoluble membrane residues indicated that both the succinate dehydrogenase and the adenosine triphosphatase antigens were released with a full (or enhanced) catalytic potential at or below concentrations of SDS required to effect maximal solubilization of the enzyme in question. Evidence is also presented to suggest that the more acidic of the two components detected by crossed immunoelectrophoresis for the heterogeneous adenosine triphosphatase antigen is more sensitive to SDS than is the other. Both succinate dehydrogenase and adenosine triphosphatase lost catalytic activity and were denatured at protein/SDS ratios lower than 3.4:1.
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PMID:Immunochemical analysis of triton X-100-insoluble residues from Micrococcus lysodeikticus membranes. 16 Apr 15

Mitochondria from a rat mammary tumor (R3230AC) have been compared with mitochondria from pregnant and lactating rat mammary glands, with particular attention paid to inner membrane enzymes and Transport proteins. In the tumor the mitochondrial adenosine triphosphatase was not activated by 2,4-dinitrophenol, in contrast to the mammary mitochondria from lactating or pregnant rats. Translocation of adenosine diphosphate across the inner membrane was found to be more rapid in the tumor by virtue of lovered Km adenosine diphosphate and raised Vmax. Transport of phosphate and dicarboxylic acids occurred at similar rates in all three types of mitochondria. The inner membrane proteins were also examined directly by sodium dodecyl sulfate/polyacrylamide gel electrophoresis and some differences are noted. These results, although they indicate subtle differences between the inner mitochondrial membranes of tumor as compared with those of pregnant or lactating rat mammary glands, cannot form the basis of an explanation for enhanced glucose utilization and aerobic lactic acid production in this tumor.
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PMID:A comparative study of inner membrane enzymes and transport systems in mitochondria from R3230AC mammary tumor and normal rat mammary gland. 16 45

1. The proton-translocating adenosine triphosphatase (ATPase) of bovine heart mitochondria was highly purified by extraction of submitochondrial particles with cholate, fractionation with ammonium sulfate, and sucrose gradient centrifugation in the presence of methanol, deoxycholate, and lysolecithin. 2. The preparation had a very low content of phospholipids, respiratory components, and adenine nucleotide transporter. The ATPase activity (14 o 16 micromoles/min/mg at 30 degrees) was dependent on addition of phospholipids. The purified enzyme was reconstituted with phospholipids, coupling factor 1 (F1), and the oligomycin sensitivity-conferring protein (OSCP) yielding vesicles with highly active 32Pi-ATP exchange (up to 260 nanomoles/min/mg at 30 degrees), and a proton pump driven by ATP. Site III oxidative phosphorylation was reconstituted when purified cytochrome oxidase was included. 3. The 32Pi-ATP exchange of the reconstituted vesicles was sensitive to both rutamycin and dichylohexylcarbodiimide but the ATPase activity was sensitive to rutamycin and not to dicyclohexylcarbodiimide. 4. In sodium dodecyl sulfate-acrylamide gel scans of the complex, the subunits of F1, OSCP, and three other major bands with apparent molecular weights of 32,000, 23,000, and about 11,000 were noted. Three other minor bands with estimated molecular weights of 80,000, 70,000, and 52,000 were also detected. These bands apparently represent residual trace amounts of respiratory components. Quantitative assays of individual respiratory components revealed between 0 and 3% contamination. 5. We conclude that the rutamycin-sensitive ATPase complex functions as a reversible ATP-driven proton pump.
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PMID:Purification and properties of the proton-translocating adenosine triphosphatase complex of bovine heart mitochondria. 17 16


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