Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.11.1 (protein kinase)
 81,284 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The authors studied the effect of rubidium, lithium and cesium on the ATPase system and c-AMP protein kinase in brain. They demonstrated that rubidium could replace potassium in the Na+K-ATPase system, whereas lithium and cesium had no effect on this enzyme activity in the absence of potassium. K+-dependent ATPase was activated by even low rubidium concentrations; lithium and cesium inhibited it. None of three (rubidium, lithium and cesium) affected c-AMP protein kinase.
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PMID:Effect of rubidium, lithium and cesium on brain ATPase and protein kinases. 19 47

Synthetic polypeptides were employed as substrates in kinetic analyses of the reaction mechanism for the catalytic subunit of a cyclic AMP-dependent protein kinase (ATP:protein phosphotransferase, EC 2.7.1.37) from calf thymus. This enzyme preparation was shown to catalyze the transfer of phosphate from ATP to histone H1 from calf thymus, as well as to two synthetic polypeptides, Arg-Lys-Ala-Ser-Gly-Pro (H1-6) and Arg-Arg-Lys-Ala-Ser-Gly-Pro (H1-7), corresponding to the amino acid sequence about serine-38 in calf H1. A related, basic heptapeptide corresponding to a sequence from pig liver pyruvate kinase, Leu-Arg-Arg-Ala-Ser-Leu-Gly (K), was also a substrate. The stoichiometry of peptide phosphorylation was established in each case as the transfer of 1 mol of phosphate from the gamma position of MgATP to the serine hydroxyl of 1 mol of the peptide. Steady-state, initial-velocity, kinetic parameters were determined for each substrate, using various concentrations of ATP. Under the conditions used, all synthetic peptides reacted with greater maximum velocities than whole histone H1. Nevertheless, the K(m) for H1, 54 muM, was lower than the K(m) values of the synthetic substrates. The most efficient substrate was peptide K, which had a V(max) of 50.6 mumol/min per mg of kinase and a K(m) of 63 muM. In the absence of peptide substrate no ATPase activity was detectable at a sensitivity of 0.05% of the rate of peptide phosphorylation, suggesting that ATP is not cleaved to form an unstable phosphoenzyme complex. The data are consistent with a sequential reaction mechanism involving a ternary complex between enzyme, polypeptide substrate, and ATP.
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PMID:Studies on the mechanism of phosphorylation of synthetic polypeptides by a calf thymus cyclic AMP-dependent protein kinase. 20 Sep 11

Properties of the ATP-dependent calcium transport system of heart sarcolemma are presented. Calcium accumulation (with oxalate) in sarcolemma was increased due to cAMP-dependent protein kinase and phosphorylase b kinase. Protein kinase increased the Vmax of the sarcolemmal calcium accumulation without any detectable effect on the affinity for Ca2+. Both kinases failed to stimulate calcium binding. Protein kinase catalyzed phosphorylation of membrane proteins of molecular weights of 100,000, 25,000, and 14,000. Phosphorylase b kinase also catalyzed phosphorylation of these proteins. Protein kinase stimulated ATPase activity of sarcolemma. Sarcolemma contained endogenous protein kinase and protein phosphatase activities.
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PMID:Characteristics of heart sarcolemmal calcium transport system and effect of protein kinase on sarcolemmal calcium accumulation. 20 83

Phospholamban (molecular weight = 22,000), which serves as a regulator of Ca transport ATPase (molecular weight = 100,000) of cardiac sarcoplasmic reticulum (SR), becomes resistant to tryptic digestion upon phosphorylation by cAMP-dependent protein kinase (PK). The protective effect of phosphorylation is accompanied by persistence of the PK-induced stimulation of Ca transport. These findings indicate that structural alteration of phospholamban upon phosphorylation is closely associated with changes in the functional properties of cardiac SR. SR from fast-contracting skeletal muscle of rabbit does not contain a 22,000-dalton substrate for cAMP-dependent PK, nor is Ca transport stimulated by exogenous PK. SR preparation isolated from slow-contracting skeletal muscle of rabbit and dog contains phospholamban, and Ca transport was found to be increased by exogenous cAMP-dependent PK. In view of the distribution of phospholamban among different types of muscle, a hypothesis is presented to explain the relaxation-promoting effects of catecholamines in cardiac and slow-contracting skeletal muscle in which phospholamban is found. This may also account for the absence of a similar effect of catecholamines in fast-contracting skeletal muscle, which does not contain a similar substrate for PK.
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PMID:Significance of the membrane protein phospholamban in cyclic AMP-mediated regulation of calcium transport by sarcoplasmic reticulum. 20 84

A human skeletal actin.tropomyosin.troponin complex was phosphorylated in the presence of [gamma-32 P]ATP, Mg2+, adenosine 3':5'-monophosphate (cyclic AMP) and cyclic AMP-dependent protein kinase (protein kinase). Phosphorylation was not observed when the actin complex was incubated in the absence of protein kinase or 1 microM cyclic AMP. In the presence of 10(-7) M Ca2+ and protein kinase 0.1 mole of [32P]phosphate per 196 000 g of protein was incorporated. This was two-fold higher than the [32P]phosphate content of a rabbit skeletal actin complex but two-fold lower than that of a bovine cardiac actin complex. At high Ca2+, 5.10(-5) M, little change in the phosphorylation of a human skeletal actin complex occurred. Phosphoserine and phosphothreonine were identified in the [32P]phosphorylated actin complex. Polyacrylamide gel electrophoresis in sodium dodecyl sulfate showed that 60% of the label was associated with the tropomyosin binding component of troponin. The inhibitory component of troponin contained 16% of the bound [32P]phosphate. Increasing the Ca2+ concentration did not significantly decrease the [32P]phosphate content of the phosphorylated proteins in the actin complex. No change in the distribution of phosphoserine or phosphothreonine was observed. Half maximal calcium activation of the ATPase activity of reconstitute human skeletal actomyosin made with the [32P] phosphorylated human skeletal actin complex was the same as a reconstituted actomyosin made with an actin complex incubated in the absence of protein kinase at low or high Ca2+.
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PMID:Phosphorylation of an actin.tropomyosin.troponin complex from human skeletal muscle. 20 9

Two types of plasma membrane were purified from canine distal renal medulla by the techniques of differential and zonal density-gradient centrifugation followed by free-flow electrophoresis. One group of plasma membranes was identified as basal-laterally derived based on a 30-fold enrichment of Na-K-ATPase, a 20-fold enrichment of vasopressin-stimulated adenylate cyclase, and a 33-fold enrichment of [3H]vasopressin binding sites. The second type of plasma membrane was free of these markers, but had a cholesterol and phospholipid composition similar to them. Alkaline phosphatase also had a similar distribution in the two fractions. This lighter membrane fraction contained a membrane-bound cyclic AMP-dependent protein kinase as well as substrate for this kinase. In addition there was a 26-fold enrichment of specific activity of an anion (SO32-)-activated ATPase which was insensitive to mitochondrial ATPase inhibitor protein, in contrast to the mitochondrial fraction of the tissue. Based on the relative preponderance of collecting duct tissue in the distal medulla and the yield of membrane protein, these membranes are tentatively identified as containing apical membranes of the collecting duct.
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PMID:Purification of distinct plasma membranes from canine renal medulla. 20 99

Calcium transport by cardiac sarcoplasmic reticulum (SR) was compared in hyperthyroid (HT) and euthyroid (ET) rats. Both Ca2+ uptake (97 +/- 3.1 nmol/mg per min in HT vs. 63 +/- 2.9 nmol/mg per min in ET, P less than 0.01) and CA2+ -stimulated ATPase activity (61 +/- 4.1 vs. 37 +/- 1.6 nmol Pi/mg per min, P less than 0.01) were higher in the thyroxine-treated animals. These changes were accompanied by enhanced cyclic AMP-dependent phosphorylation of cardiac SR in hyperthyroid rats (180 +/- 4.3 pmol Pi/mg per min vs. 117 +/- 4.2 pmol Pi/mg per min, P less than 0.01). SDS-polyacrylamide gel electrophoresis of cardiac SR showed that phosphorylation of a 22,000-dalton protein (phospholamban) primarily accounted for the differences between the two groups. There was no difference in the rate of SR dephosphorylation by endogenous phosphoprotein phosphatase between HT and ET rats. Differences in cyclic AMP-dependent phosphorylation between the two groups were blunted in the presence of excess exogenous cyclic AMP-dependent protein kinase. These results suggest that increased levels or activity of endogenous cyclic AMP-dependent protein kinases may partially explain enhanced calcium transport by the cardiac SR of hyperthyroid animals.
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PMID:Enhanced phosphorylation of myocardial sarcoplasmic reticulum in experimental hyperthyroidism. 20 50

Human renal (Na+ + K+)-ATPase (ATP phosphohydrolase, EC 3.6.1.3) preparations which exhibited a non-linear reaction rate, contained high levels of membrane-bound cyclic AMP-dependent protein kinase, while this latter activity was much less or absent in purified preparations. A non-linear reaction rate was observed in a purified preparation of (Na+ + K+)-ATPase by reconstituting the enzyme into lipid vesicles with cyclic AMP-dependent protein kinase. The addition of cyclic AMP to the ATPase assay of these lipid vesicles inactivated the (Na+ + K+)-ATPase. The cytoplasmic fraction of the cell contained a nondialyzable factor, which prevented (or reversed) the cyclic AMP-mediated inactivation of the enzyme.
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PMID:Reversible in activation of purified (Na+ + K+)-ATPase from human renal tissue by cyclic AMP-dependent protein kinase. 20 25

The recently discovered heat-stable inhibitor protein of the Ca2+-activated cyclic nucleotide phosphodiesterase (Sharma, R. K., Wirch, E. & Warg, J. H. (1978) J. Biol. Chem., in press) has been purified 238 214-fold from bovine brain extract using an affinity column of the modulator protein--Sepharose 4B conjugate. The purified sample appears to be homogeneous as judged by sodium dodecyl sulphate (SDS) gel electrophoresis. The protein band has a mobility corresponding to that of a polypeptide of molecular weight 68 000. Since the heat-stable inhibitor protein has a molecular weight of 70 000 under nondenaturing conditions, it suggests that it is a monomeric protein. The protein has no inhibitory activity toward the cAMP-dependent protein kinase or protein phosphatase. The purified sample has been tested for various enzyme activities which include ATPase, GTPase, cAMP phosphodiesterase, cGMP phosphodiesterase, 5'-nucleotidase, and protein kinase. None of these activities are exhibited by the purified sample.
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PMID:Purification of the heat-stable inhibitor protein of the Ca2+-activated cyclic nucleotide phosphodiesterase by affinity chromatography. 20 31

Troponin inhibitory factor, TNI, was prepared by affinity chromatography from different mammalian hearts. (i) Structure. These different TNI have the same M.W. (28000), which is higher than that found in rabbit skeletal muscle (23000). Nevertheless they differ with respect of their charge as shown by alkaline urea polyacrylamide gel electrophoresis using cardiac TNI which has previously been bound to an excess of skeletal troponin Ca2+-binding factor. These changes do not correlate with the PO4 content of TNI. They are associated with structural differences demonstrated by peptide mapping of the unfolded molecule after papain treatment. The structure of cardiac TNI from rat and rabbit differs clearly from that of crow and pig. (ii) Biological activity. These different TNI have the same inhibitory effect on skeletal actomyosin. ATPase, the same content of PO4 and the same ability to be phosphorylated in-vitro by a bovine heart c-AMP-dependent protein kinase.
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PMID:A comparative study of the cardiac troponin inhibitory factor (TNI) from mammalians. 20 99


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