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)

Phosphoryl group transfer from ATP to ADP occurred in the isolated membrane of catecholamine storage vesicles. The reaction was accelerated by extraction of the membranes with 50% (v/v) acetone and by treatment with 1% (v/v) Triton X-100. The phosphoryl group transfer reaction was activated by Mg2+ and by Mn2+. The activation profile differed from that obtained for the ATPase activity. The Michaelis-Menten kinetics of the phosphoryl transfer reaction were not entirely linear. From the linear parts of the double reciprocal plots KmATP approximately equal to 1 mM and KmADP approximately equal to 0.4 mM was obtained. All lines of the double reciprocal plots intersected indicating a sequential reaction mechanism. The reaction exhibited a narrow specificity for nucleoside diphospate and a broader one for nucleoside triphosphate indicating that ADP was the true substrate. The transfer reaction was slightly inhibited by AMP, orthophosphate and P1, P5-di(adenosine-5')pentaphosphate. The thiol reagents, N-ethylmaleimide and para-chloromercuribenzoate (PCMB), affected the ATPase activity and the phosphoryl transfer activity differently: with the blockade of 2.4 essential thiol equivalents by N-ethylmaleimide the ATPase was inhibited 50% and net uptake of catecholamine ceased, while the phosphoryl transfer remained unimpaired. PCMB affected both, the ATPase activity and phosphoryl transfer reaction. Treatment of the membranes with dithioerythritol prevented the PCMB-induced inhibition of the phosphoryl transfer, but was ineffective in protecting the ATPase activity, indicating that different thiol groups must be involved in the both enzymatic activities.
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PMID:Partial characterization of a phosphoryl group transferring enzyme in the membrane of catecholamine storage vesicles. 16 May 8

The antigenic composition and molecular structure of the plasma membrane of Streptococcus pyogenes (group A; M type 6) were studied by crossed immunoelectrophoresis (XIE) and other related quantitative immunoelectrophoretic techniques. After establishment of a reference pattern of 29 immunoprecipitates, the relative differences in amounts of individual antigens contained in membranes isolated from cells that were harvested during the exponential or stationary phase of growth were examined. Relative increases and decreases in amounts of individual antigens were estimated from the areas subtended by immunoprecipitates after XIE of Triton X-100 extracts. The asymmetric distribution of antigens on the inner and outer surfaces of the membrane was established in absorption experiments with intact, stable protoplasts. Of the 29 immunoprecipitates, 8 appeared to contain antigens exposed on the outer surface of the membrane, whereas 11 appeared to contain antigens either located on the inner surface or unexposed. Six antigens appeared to have limited exposure on the outer surface, and four others remain to be assigned. Certain immunoprecipitates were characterized with respect to enzymatic activity or interaction with the lectin concanavalin A. Reduced nicotinamide adenine dinucleotide dehydrogenase (EC 1.6.99.3), adenosine triphosphatase (EC 3.6.1.3), and polynucleotide phosphorylase (EC 2.3.7.8) were demonstrated by zymogram techniques. The latter two activities were present within the same immunoprecipitate, suggesting the occurrence of a multienzyme complex. In addition, the areas under the immunoprecipitates containing the three enzymatic activities were not affected by absorption of antimembrane immunoglobulin with intact protoplasts and thus appeared to be located on the inner surface of the membrane. The results from absorption experiments also suggested that the exposure of outer protoplast surface antigens was greater on protoplasts from exponential-phase cells than on those from stationary-phase cells, even when found in increased amounts in the latter.
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PMID:Quantitative immunoelectrophoretic analysis of Streptococcus pyogenes membrane. 16 Aug 91

Active transport vesicles of Escherichia coli were shown to possess low levels of energy-independent and energy-dependent nicotinamide nucleotide transhydrogenase activities. Breakage of such vesicles in a French pressure cell resulted in a fraction which had an 8-10-fold increased respiration- and ATP-driven transhydrogenase activities. Stimulation of the ATPase activity in vesicles with Triton X-100 was also paralledled by a 2-fold increase in the energy-independent transhydrogenase. Disruption of the vesicles similarly resulted in increases in the energy-independent transhydrogenase, NADH and succinate oxidase activities but a decrease in succinate supported proline uptake. In the light of these findings, the "sidedness' of the vesicle membranes is discussed.
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PMID:Energy-linked and energy-independent transhydrogenase activities in Escherichia coli vesicles. 16 48

Beef brain cortex adenylate cyclase (ATP pyrophosphate-lyase (cyclizing) EC 4.6.1.1) activity is 84--88% inhibited by 5 - 10(-5) M ethyleneglycol-bis-(beta-aminoethyl ether)N,N'-tetraacetic acid in the absence of F- but only 50--60% inhibited by 5 - 10(-5) M ethyleneglycol-bis-(beta-aminoethyl ether)N,N'-tetraacetic acid in the presence of F-. In either case, further increase in EGTA concentration did not alter the degree of inhibition. The inhibition can be completely reversed in both cases by addition of 3 - 10(-5) M Ca2+, (yielding a [free Ca2+] of approximately 2 - 10(-6) M) and 5 - 10(-5) M Mn2+ or Co2+ and partially by 5 - 10(-5) M Sr2+ but not by addition of 5 - 10(-5) M Ba2+, Zn2+, Ni2+ or Fe2+. A [free Ca2+] of 7.2 - 10(-5) M markedly inhibited cyclase activity in the presence of F-. Solubilization by 1.8% Triton X-100 resulted in an enzyme preparation no longer stimulated by NaF and 100% inhibited by the addition of 5 - 10(-5) M ethyleneglycol-bis-(beta-aminoethyl ether)N,N'-tetraacetic acid either in the absence or presence of NaF. However, in contrast to ethyleneglycol-bis-(beta-aminoethyl ether)N,N'-TETRAACETIC ACID, EDTA had no measurable effect on adenylate cyclase either in the presence or absence of NaF and ethyleneglycol-bis-(beta-aminoethyl ether)N,N'-tetraacetic acid did not affect ATPase or phosphodiesterase activities. The data is rationalized by the postulation of two independent enzyme components in brain cortex: one component is about six-fold activated by NaF and the NaF effect is enhanced by low concentrations of Ca2+ and Mg2+. A second component is totally Ca2+ dependent and inhibited by high concentrations of F-. Mn2+, Co2+ and Sr2+ appear to be in vitro Ca2+ substitutes for both enzyme systems. On this basis, Triton X-100 treatment results in about a three-fold increase in specific activity of the Ca2+ dependent cyclase component but a complete abolition of the NaF stimulated component.
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PMID:Differentiation of fluorides-stimulated and non-fluoride-stimulated components of beef brain cortex adenylate cyclase cy calcium ions, ethyleneglycol-bis-(beta-aminoethyl ether) N,N'-tetraacetic acid and Triton X-100. 16 52

Protein kinase activity was determined in subcellular fractions of rat testis interstitial tissue after incubation of the intact tissue with LH (luteinizing hormone) in vitro. Various factors that might have changed the activity of this enzyme during preparation of the fractions before assay were also investigated. The following results were obtained. 1. LH and 3-isobutyl-1-methylxanthine (a phosphodiesterase inhibitor) added together during incubation of the interstitial tissue caused a twofold increase in the protein kinase activity in the total tissue homogenate and subcellular fractions (12000g X 5 min pellet and 105000g X 60 min supernatant and pellet). 2. A decrease of approx. 40% in the total amount of protein kinase recovered in the soluble fraction (105000g supernatant) occurred in tissue incubated with LH and 3-isobutyl-1-methylxanthine when compared with the controls. No change in total activity was found in the other fractions. 3. LH and 3-isobutyl-1-methylxanthine caused an increase in cyclic AMP concentration in the soluble fraction (from 30 +/- 6 to 450 +/- 40 pmol/mg of protein, means +/- S.E.M., n = 4), but there was little or no increase in the particulate fractions [from 9 +/- 1 to 13 +/- 3 pmol/mg of protein (n = 3) and from 6 +/- 2 to 23 +/- 11 pmol/mg of protein (n = 3) in the 12000g and 105000g pellets respectively]. 4 Addition of 3-isobutyl-1-methylxanthine alone had little effect on protein kinase activity or cyclic AMP concentrations. 5. Little or no protein kinase activity could be demonstrated in subcellular particulate fractions unless Triton X-100 was added; the effect of this detergent was shown to be at least partly due to the inhibition of adenosine triphosphatase activity. 6. In the presence of Triton X-100 approx. 57% of the total protein kinase activity in the homogenate was found in the 105000g supernatant compared with 11% in the 105000g pellet and 32% in the 12000g pellet. 7. In contrast with adipose-tissue protein kinase [Corbin et al. (1973) J. Biol. Chem. 248, 1813-1821] the relative amounts of cyclic AMP-dependent and -dependent enzyme were not affected by dilution of the interstitial-tissue fractions. NaCl (0.5 M) decreased the estimated total amount of protein kinase activity.
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PMID:Protein kinase activity in rat testis interstitial tissue. Effect of luteinizing hormone and other factors. 18 Sep 76

The time course of binding of N-ethylmaleimide (NEM) to the SR was measured at pH 7.5 in the presence or absence of ATP or ADP. The following results were obtained. 1. Both in the presence and absence of nucleotide, the ATPase [EC 3.6.1.3] activity decreased linearly with increase in the amount of NEM bound to the fragmented sarcoplasmic reticulum (SR), and was inhibited almost completely by the binding of 2 moles of NEM per 10(5) g of the SR protein. 2. The amount of NEM incorporated into the ATPase (M.W.=105,000) was measured by SDS disc-gel electrophoresis. It was shown that the ATPase activity was inhibited almost completely by the binding of 2 moles of NEM per mole of ATPase. 3. The rate of binding of NEM to SR decreased by 30-40% in the presence of either ATP or ADP. The concentrations of both ATP and ADP for half-saturation were 0.1-0.2mM. 4. The effect of nucleotide on the rate of binding of NEM was not changed by the presence of Ca2+ and Mg2+ ions. Similar effects were also observed even when the SR membranes were solubilized with Triton X-100. It is suggested from these results that one or two SH groups are located in the active site of the SR ATPase, and that conformational changes are induced by the addition of ATP and ADP.
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PMID:Chemical modification of the Ca2+-dependent ATPase of sarcoplasmic reticulum from skeletal muscle. I. Binding of N-ethylmaleimide to sarcoplasmic reticulum: evidence for sulfhydryl groups in the active site of ATPase and for conformational changes induced by adenosine tri- and diphosphate. 18 70

A new method has been developed for isolating synaptic junctional complexes (SJC) of high structural integrity. The major step in the isolation involves homogenization of a synaptosomal membrane (SM) fraction in a biphasic system consisting of Freon 113 and an aqueous phase containing 0.2% Triton X-100. Well-preserved SJCs, along with membrane vesicles, were recovered in the aqueous phase after low-speed centrifugation of the homogenate. The membranes were subsequently separated from the SJCs by centrifugation on a discontinuous sucrose density gradient. The purity and identity of subcellular fractions were monitored by thin sectioning electron microscopy, using specific and nonspecific staining methods. From the electron microscope studies we conclude that SJCs and their components occupy about 65% of the area covered by structures in this fraction. The assay of enzyme activities indicates that homogenization in Triton-Freon and subsequent steps of the isolation procedure affect the activities of Na, K-ATPase, cytochrome oxidase, and acid phosphatase to different extents, but do not cause total inactivation. Electrophoresis of the SJC-enriched fraction on sodium dodecyl sulfate-polyacrylamide gels has demonstrated that a polypeptide which co-migrates with tubulin is the major component in this fraction, and that a polypeptide co-migrating with actin is also present.
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PMID:Isolation of synaptic junctional complexes of high structural integrity from rat brain. 18 64

The effects of N-1-oxyl-2,2,6,6-tetramethyl-4-piperidinyl)maleimide(SLM) on the pellet height response and ATPase activity of glycerinated Triton X-100 extracted cilia of Tetrahymena pyriformis have been studied. Preincubation of cilia with SLM caused complete inhibition of the pellet height response and an initial increase in ATPase activity followed upon longer exposure to SLM by inhibition of ATPase. The effect of SLM on extracted 30S dynein was the reverse of that for whole cilia: ATPase activity was increased when 30S dynein was added to a mixture of ATP and SLM and inhibited when the 30S dynein was preincubated with SLM. The activity of 14S dynein was only inhibited by SLM. Electron spin resonance spectra of ciliary axonemes that had reacted with SLM for various times showed that much of the covalently bound SLM was strongly immobilized even after 1 min of reaction, when ATPase activity increased twofold. The proportion of strongly immobilized label increased with longer times of reaction. Addition of ATP to SLM-labeled axonemes caused a small decrease in the height of the spectral peak corresponding to strongly immobilized label as compared with that of weakly immobilized label, indicating an increase in rotational freedom of some covalently bound label. The results suggest that ATP causes a conformation change affecting a sulfhydryl group(s) involved in the mechanochemical system. It was also shown that beta,gamma-methylene ATP(AMP-PCP) is an inhibitor of dynein ATPase. This analogue of ATP is not hydrolyzed by whole cilia or by the extracted dyneins and does not cause a pellet height response. With Mg2+ as divalent cation, AMP-PCP inhibits 30S dynein more than it inhibits 14S dynein; with Ca2+, the inhibition of 30S dynein is reduced, and there is no inhibition of 14S dynein. Under conditions where AMP-PCP inhibited 30S dynein ATPase it was much less effective than ATP in protecting against the loss of ATPase activity by SLM. Although SLM inhibited Mg2+-activated 14S and 30S dyneins in solution, it did not inhibit ciliary ATPase activity. These results support the view that at least 2 SH groups are involved in ciliary motility and that their reactivity to SH reagents depends on whether the dyneins are in situ or have been extracted.
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PMID:Effect of spin-labeled maleimide on 14S and 30S dyneins in solution and on demembranated ciliary axonemes. 19 83

Membrane preparations of erythrocytes from normal and P. chabaudi-infected mice and membrane preparations of P. chabaudi-infected and uninfected erythrocytes from infected mice and separated by zonal centrifugation were characterized by the pattern of proteins and extracted glycoproteins obtained by SDS-polyacrylamide gel electrophoresis and by the specific activities of membrane associated enzymes. The protein pattern of the membrane preparation of infected erythrocytes showed similar differences from membrane preparations of normal erythrocytes as those described by Weidekamm et al. for P. berghei. The pattern of glycoproteins extracted by the chloroform-methanol method showed characteristic differences as compared to the controls. A new band (PASi) with a molecular weight of about 165,000 corresponds with the protein band IIa. In membrane preparations of normal erythrocytes and of nonparasitized erythrocytes separated from parasitized erythrocytes by zonal centrifugation was no difference in specific activities of ATPase, adenylate kinase and acetylcholinesterase. Adenylate kinase activity was markedly increased and acetyl-cholinesterase activity was slightly increased in membrane preparations of infected cells. Specific activities of ATPase of membrane preparations of normal and parasitized erythrocytes did not show significant differences. There was a decrease in enzyme activity of ATPase and an increase of acetylcholinesterase in Triton X 100 containing samples. Specific activities of an acid phosphatase were lower in membrane preparations of parasitized cells than in the controls.
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PMID:Plasmodium chabaudi-infection of mice: specific activities of erythrocyte membrane-associated enzymes and patterns of proteins and glycoproteins of erythrocyte membrane preparations. 19 21

A postsynaptic density (PSD) fraction, including some adherent subsynaptic web material, has been isolated from dog cerebral cortex by a short-procedure modification of methods of Davis and Bloom (21, 22) and Cotman and Taylor (20), using Triton X-100. The fraction has been visualized by thin-section, replica, and negative (phosphotungstic acid) staining electron microscopy and its proteins separated by high-resoltuion SDS gel electrophoresis. Morphologically, the preparation seems to be quite pure, with very little membrane contamination. The density is composed of protein, no nuclei acids, and very little phospholipids being detectable. The fraction had no ATPase or GTPase activity, but it did have a very small amount of cytochrome c oxidase activity (of a specific activity less than 0.5 percent that of a mitochondrial fraction) and a small amount of 5'- nucleotidase activity (of a specific activity between 6 and 7 percent that of a synaptic membrane fraction). Electron micrographs reveal cup-shaped structures approximately 400nm long and approximately 40nm wide, made up of apparent particles 13-28nm in diameter. However, en face views, and particularly micrographs of replicas and PTA-stained preparations, reveal a disk-shaped structure, outside diameter approximately 400 nm, in which filaments are seen to extend from the central part of the density. High resolution gel electrophoresis studies indicated some 15 major proteins and perhaps 10 or more minor ones; the predominant protein had a mol wt of 51,000, followed by ones at 45,000, 40,000, 31,000, 26,000, and several at 100,000. A comparison by gel electrophoresis of density fraction proteins with those of a lysed synaptosomal membrane fraction containing some adherent densities indicated some comigrating proteins, but the major membrane fraction protein, mol wt 52,000, was not found in the density fraction. Antibodies raised against the density fraction reacted with a preparation of solubilized synaptic membrane proteins. By both these criteria, it was considered that the density and the synaptic membrane have some proteins in common. By separately mixing (125)I-labeled myelin, synaptic vesicle, and mitochondrial fraction proteins with synaptosomes, and then isolating the density fraction from the mixture, it was concluded that a major 26,000 mol wt density fraction protein was common to both mitochondria and density, that none of the proteins of the density were contaminants from the mitochondrial fraction, that a minor approximately 150,000 band was a contaminant from the synaptic vesicle fraction, and that the moderately staining PSD fraction protein of 17,000 mol wt band was the result of contamination by the major basic protein of myelin. On the basis of the marker enzymatic assays and the mixing experiments, it is considered that the density fraction is moderately pure biochemically, and that its protein composition, aside from a few exceptions noted above, reflects its in situ character.
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PMID:The structure of postsynaptic densities isolated from dog cerebral cortex. I. Overall morphology and protein composition. 19 6


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