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)

Troponin was isolated from striated adductor muscles of the "Akazara" scallop (Chlamys nipponensis akazara), and purified in an active form by DEAE-cellulose (Whatman DE52) column chromatography and subsequent gel filtration on Sephacryl S-300. According to sodium dodecyl sulfate-gel electrophoresis and densitometry, Akazara troponin is composed of three components having molecular weights of 52,000, 40,000, and 20,000 in a molar ratio of 1:1:1. The three components were separated from each other by column chromatography in the presence of 6 M urea and 1 mM EDTA on SP-Sephadex C-50 and DEAE-cellulose. The Mr 20,000 component was regarded as troponin C according to the Ca2+-binding properties, which was found to bind 0.7 mol of Ca2+/mol at 0.1 mM Ca2+. The association constant of Ca2+ to troponin C was estimated to be 5 X 10(5) M-1, and was not affected by the addition of 2 mM MgCl2. The Mr 52,000 component appeared to be troponin I, since it inhibited, together with Akazara tropomyosin, both Mg-ATPase and superprecipitation activities of actomyosin reconstituted from rabbit myosin and actin, and the inhibition of the ATPase activity was diminished by the addition of Akazara troponin C. Finally, the Mr 40,000 component appeared to be troponin T, since it co-precipitated with actin-tropomyosin filament and was indispensable with Akazara troponin C and the Mr 52,000 component (troponin I) for conferring the Ca2+ sensitivity to reconstituted actomyosin.
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PMID:Troponin from Akazara scallop striated adductor muscles. 294 90

LY195115 selectively inhibited the peak III isozyme of cardiac cyclic nucleotide phosphodiesterase (PDE) eluted from DEAE-cellulose columns. Inhibition curves were biphasic, suggesting heterogeneity within this preparation. Since peak III PDE is reported to be derived from membranes, effects of LY195115 upon PDE associated with cardiac membranes were examined. LY195115-sensitive PDE measured in the various membrane fractions correlated well with the sarcoplasmic reticulum marker Ca2+-ATPase (r = 0.94; p less than 0.001), but not with Na+,K+-ATPase or azide-sensitive ATPase. Membrane disruption failed to reveal latent LY195115-sensitive PDE in sarcolemmal vesicles known to be primarily right side out. The results suggest that LY195115-sensitive PDE is located within sarcoplasmic reticulum membranes with a distribution similar or identical to that of Ca2+-ATPase. Accordingly, LY195115-sensitive PDE was referred to as SR-PDE. A subfraction of sarcoplasmic reticulum vesicles (free SR vesicles) was sufficiently homogeneous with respect to SR-PDE activity to carry out steady state kinetic studies. Double reciprocal plots of cAMP hydrolysis were linear, yielding Km and Vmax values of 0.46 +/- 0.03 microM and 700 +/- 90 pmol/min/mg of vesicle protein, respectively. LY195115 was a linear competitive inhibitor of SR-PDE with a Ki of 80 +/- 10 nM. -LogIC50 values for inhibition of SR-PDE by a series of structural analogues of LY195115 correlated highly with published -logED50 values for stimulation of cardiac contractility in vivo (r = 0.91, p less than 0.001). Consequently, in vivo effects of LY195115 upon the heart appear to result primarily from competitive inhibition of SR-PDE, or from binding to a site with a topography similar or identical to that of the catalytic site of SR-PDE.
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PMID:LY195115: a potent, selective inhibitor of cyclic nucleotide phosphodiesterase located in the sarcoplasmic reticulum. 294 29

SR vesicles from rabbit slow-twitch muscle reveal high activity (0.7-0.9 mumol/mg X min) of "basic" or Mg2+-ATPase. This enzyme differs in its biochemical properties from the well characterized Ca2+ pump ATPase. It is active in millimolar concentration of magnesium or calcium. The activity is inhibited by various detergents except for digitonin. This enzyme seems to be an integral membrane protein since it remains in the membrane after removal of peripheral proteins with EDTA. It can be partially solubilized from the membrane using digitonin without a decrease in specific activity. Ion exchange chromatography on DEAE-Sephacel of the post digitonin supernatant allows us to obtain a 5-fold increase in Mg2+-ATPase specific activity concomitantly with the enrichment in two proteins of Mr = 30,000 and 150,000.
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PMID:Characterization of Mg2+-ATPase from slow-twitch muscle membranes. 295 39

C. elegans contains a microtubule binding protein that resembles both dynein and kinesin. This protein has a MgATPase activity and copurifies on both sucrose gradients and DEAE Sephadex columns with a polypeptide of Mr approximately 400 kd. The ATPase activity is 50% inhibited by 10 microM vanadate, 1 mM N-ethyl maleimide, or 5 mM AMP-PNP; it is enhanced 50% by 0.2% Triton. The 400 kd polypeptide is cleaved at a single site by ultraviolet light in the presence of ATP and vanadate. In these ways, the protein resembles dynein. The protein also promotes ATP-dependent translocation of microtubules or axonemes, "plus" ends trailing. This property is kinesin-like; however, the motility is blocked by 5 microM vanadate, 1 mM N-ethyl maleimide, 0.5 mM ATP-gamma-S, or by ATP-vanadate-UV cleavage of the 400 kd polypeptide, characteristics that differ from kinesin. We propose that this protein is a novel microtubule translocator.
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PMID:Identification of a microtubule-based cytoplasmic motor in the nematode C. elegans. 295 72

Heart sarcolemma has been shown to contain an ATPase hydrolyzing system which is activated by millimolar concentrations of divalent cations such as Ca2+ or Mg2+. Although Ca2+-dependent ATPase is released upon treating sarcolemma with trypsin, a considerable amount of the divalent cation dependent ATPase activity was retained in the membrane. This divalent cation dependent ATPase was solubilized by sonication of the trypsin-treated dog heart sarcolemma with 1% Triton X-100. The solubilized enzyme was subjected to column chromatography on a Sepharose-6B column, followed by ion-exchange chromatography on a DEAE cellulose column. The enzyme preparation was found to be rather labile and thus the purity of the sample could not be accurately assessed. The solubilized ATPase preparations did not show any cross-reactivity with dog heart myosin antiserum or with Na+ + K+ ATPase antiserum. The enzyme was found to be insensitive to inhibitors such as ouabain, verapamil, oligomycin and vanadate. The enzyme preparation did not exhibit any Ca2+-stimulated Mg2+ dependent ATPase activity. Furthermore, the low affinity of the enzyme for Ca2+ (Ka = 0.3 mM) rules out the possibility of its involvement in the Ca2+ pump mechanism located in the plasma membrane of the cardiac cell.
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PMID:Solubilization of a divalent cation dependent ATPase from dog heart sarcolemma. 296 78

Subfragment-1 of rabbit atrial and thyrotoxic ventricular myosin (V1 isomyosin) has been prepared and purified by DEAE-cellulose column chromatography. Pyrophosphate-polyacrylamide gel electrophoretic patterns and column chromatographic profile of the atrial subfragment differ from those of thyrotoxic ventricular myosin subfragment-1. On the other hand, Ca2+, Mg2+ and actin-activated ATPase activities of these subfragments are identical. Comparison of the peptide mapping by limited proteolysis in the presence of sodium dodecyl sulfate of the heavy and the light subunits of these subfragments reveals that the patterns for the heavy chain peptides of these subfragments are substantially similar but their light chain peptide patterns differ. The results suggest that the enzymatic and structural similarities that have been recognized between these isoenzymes using intact myosin hold true for the myosin subfragment-1. The differences between these subfragments are due to the differences in the light chains associated with them.
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PMID:Comparison of ATPase activities and heavy chains of rabbit atrial and thyrotoxic ventricular myosin subfragment-1. 297 51

Highly purified membrane-bound Na,K-ATPase from pig kidney outer medulla was dissolved in the non-ionic detergent C12E8. Chromatography of the dissolved material on a DEAE matrix yielded enzymatical material having a ouabain-binding capacity of 6.9 nmoles per mg protein (measured according to Lowry et al., with bovine serum albumin as standard). This material, which after addition of lipids had the same K+-phosphatase turnover as the membrane-bound enzyme, could consist entirely of live molecules with a molecular weight of 145 kDa, a value close to that expected for alpha beta-promoters of Na,K-ATPase.
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PMID:Solubilization and further chromatographic purification of highly purified, membrane-bound Na,K-ATPase. 300 35

An N-ethylmaleimide-sensitive ATPase was purified 100-fold from chromaffin granule membranes. The purification procedure included solubilization with polyoxyethylene 9 lauryl ether, chromatography on hydroxylapatite and DEAE-cellulose columns, and glycerol gradient centrifugations. Inclusion of phosphatidylserine and a mixture of protease inhibitors during the purification procedure was necessary to maintain the activity of the preparation. The purified preparation contained four major polypeptides with molecular masses of about 115, 72, 57, and 39 kDa, which were copurified with the ATPase activity. The 115-kDa subunit binds [14C]dicyclohexylcarbodiimide and the subunits of 115 and 39 kDa bind [14C]N-ethylmaleimide. The ATP-dependent proton uptake activity of chromaffin granule membranes is inhibited 50% with about 20 microM N-ethylmaleimide, while over 5 mM concentrations of the inhibitor were required to block the ATPase activity of the membranes. The ATPase activity of the purified enzyme was inhibited via two different affinities: a high affinity site with a Ki in the microM range and a low affinity site in the mM range, each contributing to about 50% inhibition of the enzyme. It is concluded that the proton-ATPase of chromaffin granule membranes contains at least four subunits with the 115-kDa polypeptide being the main subunit having the active site for the ATPase activity of the enzyme.
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PMID:Purification of N-ethylmaleimide-sensitive ATPase from chromaffin granule membranes. 301 78

Phosphorylase kinase phosphorylates the pure phospholipid phosphatidylinositol. Furthermore, it catalyzed phosphatidylinositol 4-phosphate formation using as substrate phosphatidylinositol that is associated with an isolated trypsin-treated Ca2+-transport adenosinetriphosphatase (ATPase) preparation from skeletal muscle sarcoplasmic reticulum. On this basis a fast and easy assay was developed that allows one to follow the phosphatidylinositol kinase activity during a standard phosphorylase kinase preparation. Both activities are enriched in parallel approximately to the same degree. Neither chromatography on DEAE-cellulose nor that on hydroxyapatite in the presence of 1 M KCl separates phosphatidylinositol kinase from phosphorylase kinase. The presence of a lipid kinase, phosphatidylinositol kinase, in phosphorylase kinase is not a general phenomenon; diacylglycerol kinase can be easily separated from phosphorylase kinase. Polyclonal anti-phosphorylase kinase antibodies as well as a monoclonal antibody directed specifically against the alpha subunit of phosphorylase kinase immunoprecipitate both phosphorylase kinase and phosphatidylinositol kinase.
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PMID:Evidence that phosphorylase kinase exhibits phosphatidylinositol kinase activity. 301 8

A high-molecular-weight protein complex that is capable of accurate transcription initiation and termination of vaccinia virus early genes without additional factors was demonstrated. The complex was solubilized by disruption of purified virions, freed of DNA by passage through a DEAE-cellulose column, and isolated by glycerol gradient sedimentation. All detectable RNA polymerase activity was associated with the transcription complex, whereas the majority of enzymes released from virus cores including mRNA (nucleoside-2'-O)methyltransferase, poly(A) polymerase, topoisomerase, nucleoside triphosphate phosphohydrolase II, protein kinase, and single-strand DNase sedimented more slowly. Activities corresponding to two enzymes, mRNA guanylyltransferase (capping enzyme) and nucleoside triphosphate phosphohydrolase I (DNA-dependent ATPase), partially sedimented with the complex. Silver-stained polyacrylamide gels, immunoblots, and autoradiographs confirmed the presence of subunits of vaccinia virus RNA polymerase, mRNA guanylyltransferase, and nucleoside triphosphate phosphohydrolase I, as well as additional unidentified polypeptides, in fractions with transcriptase activity. A possible role for the DNA-dependent ATPase was suggested by studies with ATP analogs with gamma-S or nonhydrolyzable beta-gamma-phosphodiester bonds. These analogs were used by vaccinia virus RNA polymerase to nonspecifically transcribe single-stranded DNA templates but did not support accurate transcription of early genes by the complex. Transcription also was sensitive to high concentrations of novobiocin; however, this effect could be attributed to inhibition of RNA polymerase or ATPase activities rather than topoisomerase.
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PMID:Sedimentation of an RNA polymerase complex from vaccinia virus that specifically initiates and terminates transcription. 303 83


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