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

---

Query: EC:3.6.1.3 (ATPase)
65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The purification and properties of a protein serine kinase (PK-P) extracted with Triton X-100 from membranes of bakers' yeast are described. The enzyme is virtually inactive unless either a histone or a heat-stable polypeptide from yeast membranes and Mg2+ are added. Other divalent cations substitute for Mg2+ poorly or not at all; most of them, including Mn2+, inhibit when added in the presence of 5 mM Mg2+. The enzyme is unstable but can be stabilized by addition of 0.1% Triton X-100 and 20% glycerol. The final preparation shows, on silver-stained electrophoresis gels, two major bands (Mr 41,000 and 35,000). According to gel filtration the molecular weight of the active protein is about 75,000. Of the two subunits, only the smaller one appears to be autophosphorylated. In addition to casein, the enzyme phosphorylates several proteins including the H+-ATPase (Mr 100,000) in the yeast plasma membrane. In order to demonstrate the phosphorylation of the ATPase (up to 0.9 equivalents), exposure of the latter to an acid phosphatase was required. Other phosphorylated proteins include mRNA cap-binding protein from mammalian erythrocytes and yeast, a glucocorticoid receptor protein, and a preparation of the guanine nucleotide-binding proteins Gi and Go from brain. A partial purification of a natural activator from yeast plasma membranes is described.
...
PMID:Polypeptide-dependent protein kinase from bakers' yeast. 354 2

A number of metals were examined for inhibition of a canine renal calcium, magnesium-activated adenosinetriphosphatase (Ca2+, Mg2+-ATPase). Of the 27 metals investigated, only compounds of mercury, silver, gold, and uranium demonstrated 50% inhibition of the enzyme at concentrations lower than 10(-4) M. The order of inhibitory potency was Hg greater than Ag greater than U greater than Au. Organic mercury (chlormerodrin, mersalyl, p-chloromercuribenzoate) was less potent than inorganic mercuric chloride, but organic gold sodium thiomalate was equipotent with inorganic gold chloride. The inhibition produced by each metal decreased parallel to the decrease in enzyme activity, seen as the source of enzyme moved from the outer cortex inward to the papilla of the kidney. The regions of highest activity showed the greatest inhibition by each metal, and inhibition decreased as the control activity of the tissue decreased. This variability of inhibition was not related to the protein content of the enzyme preparation. As the ATP concentration increased, the inhibition produced by U was reduced; if the Mg (but not the Ca concentration) was increased while the ATP concentration remained constant, the inhibition increased. Changes in the Ca, Mg, and ATP concentrations did not alter the inhibition produced by Hg, Ag, and Au.
...
PMID:Inhibition by metals of a canine renal calcium, magnesium-activated adenosinetriphosphatase. 611 68

Rapid Ca2+ release from Ca2+ -loaded sarcoplasmic reticulum vesicles (SR) was previously shown to occur upon the addition of micromolar concentrations of heavy metals, and the extent of Ca2+ release was dependent on the binding affinity of the metal to sulfhydryl group(s) on an SR protein (Abramson, J.J., Weden, L., Trimm, J.L., and Salama, G. (1982) Biophys. J. 37, 134a; Abramson, J.J., Trimm, J.L., Weden, L., and Salama, G. (1983) Proc. Natl. Acad. Sci. U.S.A. 80, 1526). The nature of this Ca2+ release site was examined further and found to be predominantly distributed in heavy SR (HSR) rather than light SR fractions. Ag+ -induced Ca2+ release from heavy SR was blocked by local anesthetics and ruthenium red which are known to inhibit Ca2+ release in skeletal fibers and in heavy SR, respectively. The rate of Ca2+ efflux from SR triggered by Ag+ was dependent on pH, Mg2+, and ionic strength of the medium. Efflux rates increased by a factor of 4 from pH 6.0 to 7.0 and then decreased in more alkaline reaction mixtures. Efflux rates from actively or passively loaded SR increased by a factor of 2.5 with increasing Mg2+ from 0 to 1 mM and then decreased in the range of 1 to 10 mM Mg2+. ATP-dependent Ca2+ uptake by SR was similar in 100 mM KCl and in 200 mM sucrose solutions, but the extent and rate of Ca2+ efflux induced by Ag+ were dramatically reduced with decreasing ionic strength of the medium. In solutions containing 5 mM Mg2+, the rate of Ca2+ efflux from heavy SR averaged over the first 1.5 s after the addition of Ag+ was 58 nmol of Ca2+/mg of SR/s, a value comparable to the fast initial rate of ATP-dependent Ca2+ uptake. The maximum initial rate of Ag+ -induced Ca2+ efflux from heavy SR in 1 mM Mg2+ may be comparable to the rate of Ca2+ release and tension development in muscle fibers. Our data indicate that Ag+ reacts with a protein or proteins in the SR, probably not the (Ca2+, Mg2+)-ATPase, to induce a rapid release of Ca2+, possibly from the physiological Ca2+ release site.
...
PMID:Silver ions trigger Ca2+ release by acting at the apparent physiological release site in sarcoplasmic reticulum. 620 94

An improved method has been devised for the purification of cytoplasmic dynein from sea urchin eggs (Strongylocentrotus droebachiensis and S purpuratus). This protocol introduces three changes over a previously published procedure (Hisanaga and Sakai: J Biochem 93:87, 1983)--the substitution of diethylaminoethyl (DEAE)-cellulose for hydroxylapatite chromatography, the elimination of sucrose density gradient centrifugation, and the use of phosphocellulose chromatography. These changes reduce the time and increase the efficiency of the purification procedure. The purified egg cytoplasmic dynein has enzymatic properties in common with axonemal dynein, including ionic specificity (Ca++ATPase/Mg++ ATPase = 0.8) and inhibition by sodium vanadate and erythro-9-2,3-hydroxynonyl adenine (EHNA). As assayed by silver staining of polyacrylamide gels, the cytoplasmic dynein is composed of two high molecular weight polypeptides (greater than 300 kilodaltons) that comigrate with flagellar dynein heavy chains, and lesser amounts of three lower molecular weight bands. None of these polypeptides appears to contain bound carbohydrate. The purification procedure can be modified slightly to allow the preparation of cytoplasmic dynein in only 2 days from as little as 3-5 ml of packed eggs, a 20-fold reduction over the previous method. This more rapid and efficient method will facilitate the investigation of cytoplasmic dynein in other systems where starting material is limited, including tissue culture cells and nerve axoplasm.
...
PMID:An improved purification method for cytoplasmic dynein. 621 Feb 93

Serial sections of biceps femoris muscles from 10 rapidly growing pigs were reacted for succinate dehydrogenase (SDH) and myofibrillar adenosine triphosphatase (ATPase) and were stained with silver to delineate the endomysial boundaries of their muscle fibres. The histochemistry of very small fibres (less than 0.001 mm2) was similar to that of surrounding fibres with a normal diameter. Of the small fibres, 71.5% had strong ATPase, 27.5% had weak ATPase, 22% had strong SDH, 23.8% had intermediate SDH and 54.1% had weak SDH reactions. Corresponding values for surrounding fibres with a normal diameter were 87.9% with strong ATPase, 11.8% with weak ATPase, 35.1% with strong SDH, 14.5% with intermediate SDH, and 50.5% with weak SDH reactions. An appreciable number of small fibres were histochemically unrelated to any of their surrounding fibres: 11.0% for ATPase, 12.8% for SDH, and 5.5% for both ATPase and SDH. The cross-sectional shapes of small fibres were similar to those of their surrounding fibres. It was concluded that these small fibres were probably the tapered ends of intrafascicularly terminating muscle fibres rather than new muscle fibres formed by splitting.
...
PMID:The histochemistry of very small muscle fibres in growing skeletal muscles. 622 41

Rat bone was extracted with KCl and Triton X-100, and a tartrate-resistant acid phosphatase activity was purified by protamine sulfate precipitation, ion-exchange chromatography (CM-cellulose), and gel filtration on Sephadex G-200 according to previously described procedures. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and silver staining demonstrated a major band with an apparent monomer molecular size of approximately 14,000 Da. The enzyme is active with p-nitrophenylphosphate (p-NPP) but exhibits a 5- to 10-fold higher affinity towards several nucleotides of which ATP and ADP are the most readily hydrolyzed substrates based on kinetic studies. Based on sensitivity towards proteolytic treatment and detergent removal, as well as pH-optimum studies, a single enzyme was found to be responsible for activity towards nucleotide phosphates as well as p-NPP. This nucleotide tri- and diphosphatase constitutes around 15% of the total acid phosphatase activity in rat bone. The activity with ATP as substrate in contrast to that with p-NPP was inhibited in a noncompetitive fashion by MgCl2, sodium metavanadate, and p-chloromercuribenzoate. Enzyme activity with p-NPP and ATP is dependent on the presence of KCl and detergent and is activated by Fe3+ and ascorbate. The reported characteristics of the enzyme suggest that it functions as a unique membrane acid ATPase.
...
PMID:Purification and characterization of a vanadate-sensitive nucleotide tri- and diphosphatase with acid pH optimum from rat bone. 623 50

Inhibition of adenosine triphosphatase (ATPase) by silver nitrate (AgNO3) in vitro was studied in microsomal fractions or tissue homogenates of canine brain and kidney, and human kidney. In microsomal fractions, AgNO3 was an indiscriminate inhibitor of ouabain-sensitive (Na+ + K+ ATPase) and ouabain-insensitive (Mg2+ ATPase) activities with 50% inhibition obtaining at concentrations on the order of 10(-7) to 10(-6)M. The enzyme was protected by cysteine. Changing the concentrations of Na+, K+, H+, Mg2+ and ATP did not alter the fractional inhibition of Na+ + K+ ATPase by a constant concentration of AgNO3. An aqueous suspension of silver sulfadiazine had an inhibitory potency similar to AgNO3. It was concluded that silver gives a different pattern of Na+ + K+ ATPase inhibition than other metallic inhibitors of the enzyme so far examined.
...
PMID:Inhibition of adenosine triphosphatase in vitro by silver nitrate and silver sulfadiazine. 624 May 33

[3H]Ouabain binding to intact MDCK (cultured monolayers of dog kidney) cells of 60 serial passages is dependent upon ouabain concentration, time and medium K+. By utilising high K+ incubations to estimate non-specific [3H]ouabain-binding, the concentration of ouabain giving half maximal specific binding was estimated to be 1.0 . 10(-7) M and the total maximum binding to be 2.33 . 10(5) sites/cell. Ouabain inhibition of (Na+, K+)-pump function was monitored by the cellular uptake of 86Rb over 5 min. The larger fraction of 86Rb uptake was ouabain sensitive and the ouabain concentration giving half-maximal inhibition was 2 . 10(-7) M. The cellular distribution of the (Na+ + K+)-ATPase was investigated using [3H]ouabain autoradiography of intact freeze-dried epithelial monolayers of MDCK cells grown upon millipore filter supports. Binding of [3H]ouabain is localised over the lateral cellular membranes. Autoradiographic silver grain density is close to background levels over both the apical and basal (attachment) membranes.
...
PMID:Autoradiographic localisation of [3H]ouabain bound to cultured epithelial cell monolayers of MDCK cells. 626 70

Cytosol prepared from rat preovulatory ovarian follicles contained several specific substrates which were phosphorylated by [gamma 32P] ATP in the presence of 2 microM cyclic AMP (cAMP) or 780 nM of highly purified catalytic subunit. These substrates were identified as RII, the regulatory subunit of type II cAMP-dependent protein kinase, an Mr = 43,000 protein presumed to be actin, and four other proteins with Mr = 36,500-15,000. A marked decrease in phosphorylation of these proteins was observed within 6-48 h of human chorionic gonadotropin (hCG)-induced ovulation and luteinization in hormonally primed immature rats. The phosphorylation of these proteins was also low in cytosol of corpora lutea isolated on Days 2, 4, 9, 13 and 23 of pregnancy. The decrease in phosphorylation of RII was associated primarily with a decrease in substrate content as measured by photoaffinity labeling and silver staining techniques, and not to a marked increase in phosphoprotein phosphatase and adenosinetriphosphatase (ATPase) activities. Whereas the decreased phosphorylation of other proteins is also presumed to be related to a decrease in their cytosol content, the data do not exclude the possibility that luteal tissue contains a specific phosphoprotein phosphatase which is not present in granulosa or theca cells of preovulatory follicles. We conclude that luteinizing hormone (LH) or hCG, and thereby cAMP itself, induces the rapid loss of specific phosphoproteins which may be involved in regulating cAMP action in granulosa cells.
...
PMID:Changes in content and phosphorylation of cytosol proteins in luteinizing ovarian follicles and corpora lutea. 632 74

Previous studies from this laboratory have shown actin to be a major protein of human lymphocytes (Stark, R., Liebes, L. F., Nevrla, D., and Silber, R. Biochem. Med., 27: 200-206, 1982). We now report the purification to homogeneity and characterization of actin from blood lymphocytes of normal subjects and patients with chronic lymphocytic leukemia. The recovery of the purified protein was about 20%. The properties of the lymphocyte actins were compared to each other and to those of rabbit skeletal muscle actin. Lymphocyte actin consisted of beta and gamma forms in a 2:1 ratio. The Mr 42,000 was determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Normal and leukemic lymphocyte actin had similar polymerization properties as assessed by viscosity measurements at 25 degrees and 4 degrees, and the ultrastructural appearance of the filaments was the same. Similar patterns were observed between normal and chronic lymphocytic leukemia actin tryptic digests analyzed by high-performance liquid chromatography. The Vmax of the actin-activated myosin Mg2+ ATPase activity was compared using rabbit skeletal muscle heavy meromyosin and subfragment 1 preparations. The values obtained with rabbit skeletal muscle and normal lymphocyte actin were identical. The Vmax observed with chronic lymphocytic leukemia lymphocyte actin was 70% of that obtained with normal lymphocyte actin. The amount of actin needed to produce half-maximal activation (Kapparent) of heavy meromyosin and subfragment 1 were, respectively, 26 and 25 microM for normal lymphocytes and 18 and 24 microM for chronic lymphocytic leukemia lymphocytes. The anomalous ATP activation by actin did not reflect differences in B-:T-cell subpopulations between chronic lymphocytic leukemia and normal lymphocytes. The possible significance of the observed differences between the myosin Mg2+ ATPase activation by chronic lymphocytic leukemia and normal lymphocyte actin is discussed.
...
PMID:Purification and characterization of actin from normal and chronic lymphocytic leukemia lymphocytes. 634 96


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---