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)

Conditions permitting survival (colony formation) of E. coli after treatment with colicin K have been found. Survival required K+ and Mg2+ at concentrations high enough to replace the intracellular ions lost from colicintreated cells. Either glucose minimal medium or broth could support survival. Survival was still observed after colicin-promoted efflux of Rb+ and decline in ATP levels had occurred, and after the period during which treatment with trypsin could rescue the cells on media containing low concentrations of K+. In an adenosinetriphosphate (ATP phohsphohydrolase, EC 3.6.1.3) deficient (uncA) mutant, survival after colicin treatment was observed at lower Mg2+ concentrations than those required by the wild type, and Rb+ could replace K+. Cells treated with colicin E1 (but not with colicin I2, E3, or Ib) also survived under conditions permitting survival of colicin K.
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PMID:Viability of Escherichia coli treated with colicin K. 12 2

The two halves of the ATPase, M, 115,000, from sarcoplasmic reticulum produ-ed by limited trypsin treatment have been purified in sodium dodecylsulphate. The fragment of Mr60,000 has been purified by electrophoresis on cellulose acetate slabs and that of Mr 55,000 by gel filtration. The two halves of the 60,000 Mr fragment (Mr33,000 and 24,000) produced by more extensive trypsin treatment have also been purified by gel filtration in sodium dodecylsulphate. The sum of the amino acid analyses of the constituent tryptic fragments is in good agreement with that for the whole ATPase. The amino acid compositions of the two halves of the ATPase were strikingly similar. N-terminal analysis shows that the ATPase and its constituent tryptic polypeptides all possess a single N-terminal alanine implying no further cleavage of the polypeptide by trypsin. Attempts to solubilize selectively the tryptic fragments from the membrane by a variety of denaturing and solubilising agents under a variety of conditions have proved unsuccessful, suggesting that the interaction between the tryptic polypeptides is stronger than between the lipid and the protein. The possibility that the interaction between the tryptic polypeptides includes disulphide bonding has been eliminated.
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PMID:Separation and characterisation of tryptic fragments from the adenosine triphosphatase of sarcoplasmic reticulum. 12 51

Exposure of sarcoplasmic reticulum to trypsin in the presence of 1 M sucrose results in degradation of the Mr = 102,000 ATPase enzyme to two fragments of Mr = 55,000 and 45,000 with subsequent appearance of fragments of Mr = 30,000 and 20,000. These fragments were purified by column chromatography in sodium dodecyl sulfate. Antibodies were raised against the ATPase and the Mr = 55,000, 45,000, and 20,000 fragments. There was no antigenic cross-reactivity between the Mr = 55,000 and 45,000 fragments, indicating that they were derived from a single linear cleavage of the larger enzyme. There was antigenic cross-reactivity between the Mr = 20,000 and 55,000 fragments, indicating an origin of the Mr = 20,000 fragment in the Mr = 55,000 fragment. None of the antibodies inhibited (Ca2+ + Mg2+)-dependent ATPase or Ca2+ transport. The Mr = 20,000 fragment and the Mr = 55,000 fragment were active in Ca2+ ionophore assays. The active site of ATP hydrolysis was labeled with [gamma-32P]ATP and the site of ATP binding was labeled with tritiated N-ethylmaleimide. In both cases radioactivity was found in the intact ATPase and in the Mr = 55,000 and 30,000 fragments, indicating that the Mr = 30,000 fragment was also derived from the Mr = 55,000 fragment. Amino acid composition data showed that the Mr = 45,000 fragment contained about 60% nonpolar and 40% polar amino acids, while the Mr = 55,000 fragment and the Mr = 20,0000 fragment contained about equal amounts of polar and nonpolar amino acids. Studies of the reaction of various antibodies at the external surface of sarcoplasmic reticulum vesicles showed that the ATPase was exposed, whereas calsequestrin and the high affinity Ca2+-binding protein were not. The use of antibodies against the various fragments indicated that the Mr = 55,000 fragment was in large part exposed, whereas the Mr = 20,000 and the 45,000 fragments were only poorly exposed. It is probable that the site of ATP hydrolysis in the Mr = 55,000 fragment is external, whereas the ionophore site is only partially exposed and the Mr = 45,000 fragment is largely buried within the membrane.
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PMID:Isolation and characterization of tryptic fragments of the adenosine triphosphatase of sarcoplasmic reticulum. 12 71

Two new forms of the plasma membrane ATP-ase of Micrococcus lysodeikticus NCTC 2665 were isolated from a sub-strain of the microorganism by polyacrylamide gel electrophoresis. One of them had a mol.wt of 368,000 and a very low specific activity (0.80 mumol.min-1.mg protein-1) that could not be stimulated by trypsin. This form has been called B1 (strain B, inactive). If the elctrophoresis was carried out in the presence of reducing agents (i.e., dithiothreitol) and the pH of the effluent maintained at a value of 8.5 another form of the enzyme was obtained. This had a mol.wt of 385,000 and a specific activity of 2.5-5.0 mumol.min-1.mg protein-1 that could be stimulated by trypsin to 5-10 mumol.min-1.mg protein-1. This preparation of the ATPase has been called from BA (strain B, enzyme active). The subunit composition of both forms has been studied by sodium dodecyl sulphate and urea gel electrophoresis and compared to that of the enzyme previously purified from the original strain (form A). The three forms of the enzyme had similar beta and delta subunits, with mol.wt of about 50,000 and 30,000 dalton, respectively. They also had in common the component(s) of relative mobility 1.0, whose status as true subunit(s) of the enzyme remains yet to be established. However, subunit alpha, that had a mol.wt of about a 52,500 in form A (ANDREU et al. Eur. J. Biochem. (1973) 37, 505-515), had a mol.wt similar to beta in form B1 and about 60,000 in form BA. Furthermore BA usually showed two types of this subunit (alpha' and alpha") and an additional peptide chain E) with a mol.wt of about 25,000 dalton. This latter subunit seemed to account for the stimulation by trypsin of form BA. Forms BA could be converted to B1 by storage and freezing and thawing. Conventional protease activity could not be detected in any of the purified ATPase forms and addition of protease inhibitors to form BA failed to prevent its conversion to form B1. The low activity form (B1) was more stable than the active forms of the enzyme and also differeed in its circular dichroism. These results show that M. lysodeikticus ATPase can be isolated in several forms. Although these variations may be artifacts caused by the purification procedures, they provide model systems for understanding the structural and functional relationships of the enzyme and for drawing some speculations about its function in vivo.
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PMID:Membrane adenosine triphosphatase of Micrococcus lysodeikticus. ISolation of two forms of the enzyme complex and correlation between ezymatic stability, latency and activity. 13 May 38

Sodium dodecyl sulfate polyacrylamide gel electrophoresis reveals in the rabbit skeletal muscle sarcolemma the presence of four major protein bands corresponding to molecular weight 216,000, 110,000, 44,000, 15,000, and smaller amounts of 148,000, 78,000, 68,000, 37,000, 27,000 proteins. (Na+-K+)-ATPase isolated from rabbit skeletal muscle contains 102,000, 44,000, and 32,000 protein bands. Sarcolemma is resistant to the solubilizing effect of Triton X-100, Lubrol, and deoxycholate. Sarcolemmal proteins, especially sodium-potassium-ATPase, are sensitive to digestion with trypsin.
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PMID:Characterization of sarcolemma from rabbit skeletal muscle. 13 Jun 57

The Km value for the dog heart (Na+-K+)-ATPase was 0.31 mM (MgATP), whereas the values for the concentrations of K+ and Na+ varied from 1.2 to 2.7 mM and 12 to 20 mM for half-maximal activation, respectively. The concentrations of ouabain and calcium for 50 percent inhibition of (Na+-K+)-ATPase activity varied from 2.4 to 3.2 muM and 0.5 to 1.2 mM, respectively, the inhibitory effects of these agents were pH dependent. This preparation bound about 50 nmoles of 1-anilino-8-napthaline sulfonate (ANS)/mg of protein and exhibited fluorescence attributable to the ANS-enzyme complex. Cations such as Na+,K+,Ca++, and Mg++ increased ANS-enzyme fluorescence intensity and the number of ANS binding sites but decreased the apparent ANS binding constant. The enzyme activity, ANS binding, and ANS-enzyme fluorescence were decreased by phospholipase A, phospholipase C, and trypsin treatments. Although ouabain inhibited enzyme activity and ANS-enzyme fluorescence markedly, it caused only a slight depression in ANS binding. These results extend support for the allosteric nature of the cardiac (Na+-K+)-ATPase and provide evidence for conformational changes during its activation by Na+ and K+.
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PMID:Characterization of partially purified heart sarcolemmal Na+-K+-stimulated ATPase. 13 Jun 58

Sarcolemmal Ca++-ATPase, Mg++-ATPase, and (Na+-K+)-ATPase activities were increased in late stages of heart failure in myopathic hamsters (BIO 14.6) without any changes in the adenylate cyclase activity. On the other hand, these hamsters at early and moderate stages of heart failure showed depressions in mitochondrial calcium binding and uptake and microsomal calcium binding. Sarcolemmal (Na+-K+)-ATPase was decreased in failing hearts because of substrate lack, oxygen lack, and perfusion with Ca++-free, Na+-free, or K+-free medium. Both Mg++-ATPase and Ca++-ATPase activities of sarcolemma did not change on perfusing the hearts with substrate-free, hypoxic, Na+-free, or K+-free medium. Adenylate cyclase activity decreased on substrate-free or Ca++-free perfusion. Intracellular calcium overload produced by perfusing the hearts with medium containing calcium after Ca++-free perfusion was associated with decrease in all the sarcolemmal-bound enzyme activities. All types of failing hearts employed in this study showed a dramatic shift in the electrolyte composition. Failure of the cardiac muscle to generate contractile force on treatment with trypsin was associated with defects in the functions of sarcolemma, mitochondria, and sarcoplasmic reticulum, whereas such an effect on treatment with phospholipase C was limited to alterations in the activities of sarcolemma. The data suggest that abnormality at the level of sarcolemma plays an important role in the pathogenesis of heart dysfunction; however, the degree and direction of alterations in the sarcolemmal functions seem to be dependent upon the type of heart failure.
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PMID:Role of sarcolemmal changes in cardiac pathophysiology. 13 Jun 63

By trypsin treatment of highly purified ATPase (EC 3.6.1.3) from Micrococcus sp. ATCC 398E, two enzyme modifications have been obtained. (i) ATPase Ta, which has about the same activity as untreated ATPase. (ii) A protein complex Ti, which lacks ATPase activity, but nevertheless binds ATP as shown by affinity chromatography. Trypsin primarily shortens the alpha-chains of the "native" enzyme to alpha-chains and removes the gamma-subunit, thus yielding ATPase Ta. The formation of the protein complex Ti appears to be due to additional cleavage of one alpha-chain into at least two more fractions.
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PMID:Me2+-(13 S) ATPase from Micrococcus sp. ATCC 398E. The effect of trypsin on the purified enzyme. 13 81

The nature of the protein components and their location in the sarcoplasmic reticulum membrane were studied using sarcoplasmic reticulum vesicles isolated from rat skeletal muscle and purified by a density gradient centrifugation system. On the basis of analysis by means of sodium dodecyl sulfate gel electrophoresis, the protein components appear to be similar if not identical with those reported by others for rabbit sarcoplasmic reticulum, and the relative amount of each component is also similar to that found with rabbit sarcoplasmic reticulum. Evidence is presented that radioiodine-labeled diazotized diiodosulfanilic acid is a nonpermeant labeling agent of the protein components of sarcoplasmic reticulum vesicles; this agent minimally disturbs the functional activities of these membranes. By means of this labeling agent and perturbing agents, it is concluded that the protein components with molecular weights greater than 120,000 and the (Ca2+ + Mg2+)-adenosine triphosphatase partially or totally reside on or at the external surface of the sarcoplasmic reticulum vesicles. In the case of the adenosine triphosphatase, highly controlled trypsin treatment cleaves the molecule into two products, a 65,000 molecular weight fragment and a 56,000 molecular weight fragment. The evidence indicates that the 65,000 molecular weight component of the (Ca2+ + Mg2+)-adenosine triphosphatase is located in a more exposed fashion on the external surface of the vesicles than the 56,000 molecular weight compoenet and that some adenosine triphosphatase molecules have a more exposed position on the external surface of the vesicle than others. The protein components designated by MacLennan (MacLennan, D. H. (1975) Can. J. Biochem. 53, 251-261) as "calsequestrin" and "high affinity Ca2+ binding protein" are shown not to be on the external surface of the rat sarcoplasmic reticulum vesicle but rather to reside either within the core of the membrane or on the inside surface of the vesicle. The results of this study are in agreement with the model for the organization of the protein components of the sarcoplasmic reticulum membrene recently proposed by MacLennan (MacLennan, D. H. (1975) Can. J. Biochem. 53, 251-261).
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PMID:Analysis of the arrangement of protein components in the sarcomplasmic reticulum of rat skeletal muscle. 13 99

A soluble purified form of Micrococcus lysodeikticus ATPase (form BAT, from strain B, active, trypsin-stimulated) was stimulated 100% by trypsin and this stimulation was inhibited by preincubation of the protease with phenyl methyl sulphonylfluoride. This form of the enzyme was also stimulated 125-150% by filtration on Sephadex G-200. Analysis by sodium dodecyl sulphate-gel electrophoresis showed that stimulation of this form of M. lysodeikticus ATPase was always accompanied by the disappearance of a subunit of mol. wt. 25000 (epsilon subunit). It suggests that this subunit is the natural inhibitor of M. lysodeikticus ATPase. In the case of ATPase stimulation by trypsin, a partial and limited degradation of the alpha subunit was also observed. The interaction between the epsilon subunit and the rest of the ATPase complex was reversibly affected by pH, suggesting its non-covalent nature.
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PMID:Micrococcus lysodeikticus membrane ATPase. Effect of trypsin on stimulation of a purified form of the enzyme and idenfification of its natural inhibitor. 13 93


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