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)

Soluble, oligomycin-insensitive ATPase released from beef heart mitchondria by chloroform extraction can be further purified by Sepharose 6B gel filtration. This purification increases enzyme activity 4--5 times (100-130U/mg). According to specific activity, high purity and ability to reconstitute oligomycin-sensitive complex, isolated ATPase is quite comparable with enzyme preparations isolated by other methods.
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PMID:Purification and properties of adenosine triphosphatase solubilized from beef heart mitochondria by chloroform. 14 24

Studies of the kinetics of association and dissociation of the formycin nucleotides FTP and FDP with CF1 were carried out using the enhancement of formycin fluorescence. The protein used, derived from lettuce chloroplasts by chloroform induced release, contains only 4 types of subunit and has a molecular weight of 280 000. In the presence of 1.25 mM MgCl2, 1 mol of ATP or FTP is bound to the latent enzyme, with Kd = 10(-7) or 2 . 10(-7), respectively. The fluorescence emission (lambdamax 340 nm) of FTP is enhanced 3-fold upon binding, and polarization of fluorescence is markedly increased. The fluorescence changes have been used to follow FTP binding, which behaves as a bimolecular process with k1 = 2.4 . 10(4) M-1 . s-1. FTP is displaced by ATP in a process apparently involving unimolecular dissociation of FTP with K-1 = 3 . 10(-3) S-1. The ratio of rates is comparable to the equilibrium constant and no additional steps have been observed. The protein has 3 sites for ADP binding. Rates of ADP binding are similar in magnitude to those for FTP. ADP and ATP sites are at least partly competitive with one another. The kinetics of nucleotide binding are strikingly altered upon activation of the protein as an ATPase. The rate of FTP binding increases to at least 10(6) M-1 . s-1. This suggests that activation involves lowering of the kinetic barriers to substrate and product binding-dissociation and has implications for the mechanism of energy transduction in photophosphorylation.
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PMID:Kinetics of nucleotide binding to chloroplast coupling factor (CF1). 15 22

Incubation of mitochondria from Neurospora crassa and Saccharomyces cerevisiae with the radioactive ATPase inhibitor [14C]dicyclohexylcarbodiimide results in the irreversible and rather specific labelling of a low-molecular-weight polypeptide. This dicyclohexylcarbodiimide-binding protein is identical with the smallest subunit (Mr 8000) of the mitochondrial ATPase complex, and it occurs as oligomer, probably as hexamer, in the enzyme protein. The dicyclohexylcarbodiimide-binding protein is extracted from whole mitochondria with neutral chloroform/methanol both in the free and in the inhibitor-modified form. In Neurospora and yeast, this extraction is highly selective and the protein is obtained in homogeneous form when the mitochondria have been prewashed with certain organic solvents. The bound dicyclohexylcarbodiimide label is enriched in the purified protein up to 50-fold compared to whole mitochondria. Based on the amino acid analysis, the dicyclohexylcarbodiimide-binding protein from Neurospora and yeast consists of at least 81 and 76 residues, respectively. The content of hydrophobic residues is extremely high. Histidine and tryptophan are absent. The N-terminal amino acid is tyrosine in Neurospora and formylmethionine in yeast.
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PMID:The dicyclohexylcarbodiimide-binding protein of the mitochondrial ATPase complex from Neurospora crassa and Saccharomyces cerevisiae. Identification and isolation. 15 5

The effects of ether, chloroform, and halothane on calcium accumulation and ATPase activity of rat heart microsomes and mitochondria as well as on myofibrillar ATPase activity were investigated. Chloroform and halothane depressed microsomal and mitochondrial calcium uptake and binding in a parallel fashion. Ether decreased microsomal calcium binding and mitochondrial calcium uptake to varying degrees, while mitochondrial calcium binding was slightly enhanced. Whereas ether had no effect, chloroform depressed microsomal and mitochondrial total APTase activities and halothane decreased microsomsl ATPase and slightly stimulated mitochondrial total ATPase activities. Halothane was found to depress myofibrillar Mg2+-ATPase and ether was capable of decreasing myofibrillar Ca2+-ATPase. Chloroform was seen to inhibit both myofibrillar enzymes. These results suggest that the cardiodepressant actions of volatile anesthetic agents may be due to alterations in the calcium accumulating abilities of microsomal and mitochondrial membranes while direct myofibrillar effects may contribute to the depression seen with relatively higher concentrations of anesthetics.
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PMID:Subcellular effects of some anesthetic agents on rat myocardium. 15 65

A stable and homogeneous adenosine-5'-triphosphatase (ATPase, EC 3.6.1.3) has been solubilized from Rhodospirillum rubrum (R. rubrum) chromatophores by chloroform extraction. Purification of the Ca2+-dependent ATPase activity was 200-fold. Ca2+ can be replaced by Mg2+, Cd2+, and Mn2+. The Km for Ca-ATP (0.17 mM) is increased about 5-fold during solubilization of the enzyme, whereas the Km values for Mg-ATP (0.029 mM) and Cd-ATP (0.014 mM) are not affected. The chloroform-released ATPase has a molecular weight of 400,000 +/- 30,000 and consists of the following subunits (molecular weights in parenthesis): alpha(58,000), beta(53,500), gamma(39,000), delta(18,500), and epsilon(14,000). The amino acid composition and the fluorescence spectra are presented. Besides the chloroform-released ATPase complex three other Ca2+-dependent ATPase forms have been isolated from R. rubrum chromatophores by other methods for comparison. Ultrasonication of the membranes leads to the release of an ATPase complex which is mainly composed of alpha, beta, and gamma-subunits. From an acetone powder extract an ATPase complex could be purified by affinity chromatography which is composed of four kinds of subunits (alpha, beta, gamma, delta). The same acetone powder yields an ATPase consisting of only three different types of subunits (alpha, beta, gamma) if the final purification step is preparative disc electrophoresis on 6% polyacrylamide gels instead of affinity chromatography.
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PMID:Purification, subunit structure, and kinetics of the chloroform-released F1ATPase complex from Rhodospirillum rubrum and its comparison with F1ATPase forms isolated by other methods. 15 49

1. Soluble ATPase (adenosine triphosphatase) activity is released when rat liver submitochondrial particles are shaken with chloroform, provided that ATP or glycerol is present in the suspending medium. The extraction is very rapid and appears to be complete. 2. The ATPase of the chloroform extract is about 50% pure and can be readily purified to a specific activity of 60-70mumol/min per mg of protein by (NH(4))(2)SO(4) fractionation and column chromatography on Sephadex G-200. 3. The particulate and soluble ATPases have many similar properties, including their K(m) values for ATP, activation by various metal ions, hydrolytic activity with other nucleotides and stimulation by bicarbonate ions. 4. Unlike the particulate enzyme, the soluble enzyme is cold-labile and insensitive to oligomycin. 5. The molecular weight indicated by the mobility of the soluble ATPase on Sepharose 6B is 360000. 6. The soluble ATPase combines very readily with liver submitochondrial particles depleted of ATPase by salt extraction, and oligomycin-sensitivity is restored. Very little recombination of the enzyme occurs with chloroform-extracted particles. 7. The soluble enzyme contains orcinol-reactive material, suggesting that it may be a glycoprotein. The carbohydrate content was estimated to be 1-2% by weight. 8. It is concluded that the liver ATPase obtained by the chloroform extraction method of Beechey, Hubbard, Linnett, Mitchell & Munn [(1975) Biochem. J.148, 533-537] is similar to other preparations described previously and that this method is superior in simplicity and speed.
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PMID:Purification and properties of the adenosine triphosphatase released from the liver mitochondrial membrane by chloroform. 15 21

1. Isolation of ATPase from rat liver submitochondrial particles by chloroform treatment requires the presence of ATP or ADP during enzyme solubilization. In the absence of adenine nucleotides the enzyme activity is very low although all protein components of F1-ATPase are released. The low concentrations of ATP or ADP required (5 microM) indicate that the high affinity nucleotide-binding sites are involved in enzyme stabilization. Other nucleotides tested (ITP, GTP, UTP, CTP) were found to be less effective. 2. Polyacrylamide gel electrophoresis and immunodiffusion in agar plates revealed that in the absence of adenine nucleotides a fraction of F1-ATPase released by chloroform treatment is split into fragments. The part of the dissociated enzyme molecule has a molecular weight identical with that of a beta-subunit of F1-ATPase. 3. Dissociation of the F1-ATPase molecule could also be prevented by aurovertin. 4. Crude F1-ATPase solubilized by chloroform treatment can be further purified by Sepharose 6B gel filtration. Specific ATPase activity of the purified enzyme was 90 mumol Pi/min per mg protein and the enzyme was composed of five protein subunits (alpha, beta, gamma, delta, epsilon) with molecular weights 58 000, 55 000, 28 000, 13 000 and 8000, respectively. 5. Chloroform-released F1-ATPase from rat liver mitochondria displayed immunochemical cross-reactivity with that isolated from beef heart mitochondria.
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PMID:Stabilization of rat liver mitochondrial F1-adenosine triphosphatase during chloroform-induced solubilization. 15 60

The dicyclohexylcarbodiimide-binding protein of Aspergillus nidulans has been identified as the smallest subunit of the mitochondrial ATPase complex, and has a molecular weight of approximately 8000. It is extractable from whole mitochondria and from the purified enzyme in neutral chloroform/methanol, contains 30% polar amino acids, and the N-terminal amino acid has been identified as tyrosine. Using a double-labelling technique in the absence and presence of cycloheximide, followed by immunoprecipitation of the enzyme complex with antiserum against Neuospora crassa F1 ATPase, it has been shown that this subunit is synthesized on cytoplasmic ribosomes.
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PMID:Mitochondrial ATPase complex of Aspergillus nidulans and the dicyclohexylcarbodiimide-binding protein. 15 78

1. Grinding of epimastigotes of Trypanosoma cruzi with glass powder in a mortar yielded a Mg2+-activated adenosine triphosphatase (ATPase) preparation which was highly sensitive to oligomycin. 2. Chloroform treatment of the particles resulted in the solubilization of an ATPase which was (a) activated by MgCl2; (b) slightly inhibited by CaCl2; (c) activated by sulphite and bisulphite; (d) had an optimum pH of 7.6; and (e) had a Km for ATP of 2.1 mM (in the presence of 4 mM MgCl2). 3. The solubilized enzyme was insensitive to oligomycin and leucinostatin, which inhibited the membrane-bound ATPase, though inhibited by efrapeptin and quercetin. 4. The results indicate that the chloroform-extracted enzyme is a soluble F1-ATPase similar to those isolated from mammalian mitochondria.
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PMID:Solubilization and some properties of the Mg2+-activated adenosine triphosphatase from Trypanosoma cruzi. 16 84

The subsynaptosomal distribution of the borohydride stabilizable binding of serotonin (5-HT) in the brain was investigated using various enzyme markers, such as NAD glycohydrolase (NADase), Na+, K+-activated ATPase for synaptic membranes, and monoamine oxidase (MAO) for outer mitochondrial membranes. The gross distribution of the activity of NADase and Na+, K+-activated ATPase in various membrane fractions was found to parallel the distribution of 5-HT binding in these fractions. Radioactivity bound to brain fractions was extractable with chloroform-methanol (2:1). The membranous material was solubilized by chloroform-methanol (2:1) and the recovered material, suspended in 0.32 M sucrose was found to retain its 5-HT binding capacity. The protein-phospholipid nature of the binding subcellular macromolecule was demonstrated with proteolytic and lipolytic enzymes.
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PMID:Subsynaptosomal localization and biochemical characterization of serotonin binding sites in the brain. 18 52


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