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)

Nucleoplasmic RNA polymerase II (nucleosidetriphosphate:RNA nucleotidyltransferase, EC 2.7.7.6) from calfthymus is phosphorylated by homologous cyclic AMP-independent protein kinase (ATP:protein phosphotransferase, EC 2.7.1.37). Polyacrylamide gel electrophoresis of the 32P-labeled RNA polymerase II under non-denaturing conditions revealed that both forms of the enzyme were phosphorylated. Polyacrylamide gel electrophoresis of the 32P-labeled RNA polymerase II under denaturing conditions showed that the 25 000 dalton subunit was the phosphate acceptor subunit. Partial acid hydrolysis of the 32P-labeled RNA polymerase II followed by ion-exchange chromatography revealed serine and threonine as the [32P]phosphate acceptor amino acids. Phosphorylation of the RNA polymerase II was accompanied by a stimulation of enzymatic activity and was dependent upon the presence of ATP.
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PMID:Phosphorylation of calf thymus RNA polymerase II by nuclear cyclic 3',5'-AMP-independent protein kinase. 20 18

A model synthetic peptide substrate of the cyclic AMP-dependent protein kinase (ATP:protein phosphotransferase; EC 2.7.1.37), Leu-Arg-Arg-Ala-Ser-Leu-Gly, closely resembling the local phosphorylation site sequence in porcine hepatic pyruvate kinase, was shown to be phosphorylated in vivo after microinjection into Xenopus oocytes. This result demonstrates that the microinjection technique, utilizing a synthetic peptide substrate, or possibly a synthetic substrate analog inhibitor [Kemp, B. E., Benjamini, E. & Krebs, E. G. (1976) Proc. Natl. Acad. Sci. USA 73, 1038--1042], can be used to study protein phosphorylation-dephosphorylation reactions in living oocytes. This follows, since it is clear that the injected peptide was accessible to the cellular compartment containing the protein kinase.
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PMID:In vivo phosphorylation of a synthetic peptide substrate of cyclic AMP-dependent protein kinase. 20 33

Incubation of S49 lymphoma cells with N6,O2'-dibutyryl cyclic AMP (Bt2cAMP) decreases the activities of ornithine decarboxylase (L-ornithine carboxy-lyase; EC 4.1.1.17) and S-adenosylmethionine decarboxylase (S-adenosyl-L-methionine carboxy-lyase; EC 4.1.1.50), the two principal enzymes in the pathway of polyamine synthesis. This decrease is dose-dependent, commences after a 3-hr delay, virtually abolishes the assayable activities of the two enzymes, and is not associated with a soluble inhibitor of the enzyme activities. Studies in mutant S49 clones that have altered protein kinase indicate that cAMP-dependent protein kinase mediates the decreases in enzyme activities. The dose-response pattern for the cAMP-stimulated decrease in enzyme activities parallels the pattern for the cAMP-stimulated, cell cycle-specific (G1) growth arrest of S49 cells. The activity of ornithine decarboxylase decreases faster than Bt2cAMP arrests wild-type S49 cells and, similarly, release of cells from the cAMP-stimulated arrest in G1 increases the activity of ornithine decarboxylase faster than cells exit from G1. These findings contrast with reports that cAMP induces ornithine decarboxylase in other cell types and further suggest that passage of cells through cell cycle is required for maintaining the activities of ornithine and S-adenosylmethionine decarboxylases.
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PMID:Cyclic AMP-dependent protein kinase mediates a cyclic AMP-stimulated decrease in ornithine and S-adenosylmethionine decarboxylase activities. 20 37

Incorporation of phosphorus from [gamma-32P]ATP into protein was catalyzed by specific immunoprecipitates from avian sarcoma virus (ASV)-transformed avian and mammalian cells. This incorporation was observed only when antiserum from tumor-bearing rabbits able to specifically precipitate the ASV sarcoma gene product, p60src, was used to immunoprecipitate antigens from transformed cell lysates. Immunoprecipitates of extracts from normal cells or cells infected with a transformation-defective ASV mutant showed no activity in this assay, nor did any immune complexes formed with normal rabbit serum and any of the cell extracts tested. The expression of the protein kinase activity (ATP:protein phosphotransferase, EC 2.7.1.37) was growth temperature-dependent in cells infected with an ASV mutant temperature-sensitive for the transformation. These results on an enzymatic activity associated with the ASV transforming protein are discussed in terms of protein phosphorylation as a mechanism for viral transformation.
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PMID:Protein kinase activity associated with the avian sarcoma virus src gene product. 20 79

In the isolated perfused rat heart, epinephrine produced a rapid, concentration-dependent increase in cyclic adenosine 3',5'-monophosphate (cAMP), activation of cAMP-dependent protein kinase, activation of phosphorylase, and increase in contractile force. At epinephrine concentrations of 1 micron or less, acetylcholine antagonized all these beta-adrenergic effects and also increased cyclic guanosine 3',5'-monophosphate (cGMP) levels. When used alone, acetylcholine produced a rapid elevation of cGMP and markedly diminished contractile force but did not significantly lower basal cAMP levels or cAMP-dependent protein kinase activity. The data suggest that changes in cAMP-dependent protein kinase activity can explain the antagonism of epinephrine-induced activation of phosphorylase by acetylcholine, but cannot completely account for the inhibitory effect of the cholinergic agent on contractile force.
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PMID:Interaction of acetylcholine and epinephrine on heart cyclic AMP-dependent protein kinase. 20 51

The relationship between cAMP-dependent protein kinase activity and epinephrine-produced activation of phosphorylase and increase in contractility was investigated in the intact working rat heart. Epinephrine was administered as a bolus into the superior vena cava of open-chest preparations and the hearts were rapidly frozen. cAMP increased within 5 s and returned to control within 20-30 s. Protein kinase and phosphorylase kinase activity ratios increased transiently with the same time course as that for cAMP. The phosphorylase activity ratio and the rate of left ventricular pressure development increased maximally within 15 s and returned to control in 30-60 s. Continuous infusion of epinephrine caused a sustained elevation of the protein kinase. Free catalytic protein kinase activity increased proportionately with the dose of epinephrine. The beta-adrenergic blocking agent, practolol, had no effect on the basal levels of the five parameters studied, but did prevent the epinephrine-produced increases. The results suggest that the time course of cAMP-dependent protein kinase activation is appropriate if this enzyme is to play a role in the catecholamine-induced increase in both glycogenolysis and contractility in the in vivo heart.
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PMID:Protein kinase regulation of cardiac phosphorylase activity and contractility. 20 58

A protein kinase which depends on the simultaneous presence of Ca2+ and the modulator protein for its histone phosphorylation activity has been demonstrated in rabbit skeletal muscle and partially purified. The purified enzyme was not activated by cAMP, cGMP, or incubation with trypsin. Nor was the enzyme inhibited by the protein inhibitor of cAMP-dependent protein kinase. In addition to histone, myosin light chains and phosphorylase kinase served as substrates for the protein kinase, and their phosphorylation also depended on the presence of Ca2+ and the modulator protein. The phosphorylation of phosphorylase kinase was accompanied with a marked activation of the enzyme. The results suggest that the protein kinase has multiple functions and may be involved in the mediation of Ca2+ effects in many biological processes. It is proposed that this enzyme be designated as the modulator-dependent protein kinase. The modulator-dependent protein kinase may be identical to the myosin light chain kinase; chicken gizzard light chain kinase has been shown activatable by the modulator protein (Dabrowska, R., Sherry, J. M. F., Aramatorio, D. K., and Hartshorne, D. J. (1978) Biochemistry 17, 253-258).
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PMID:The modulator-dependent protein kinase. A multifunctional protein kinase activatable by the Ca2+-dependent modulator protein of the cyclic nucleotide system. 20 40

The role of cyclic nucleotides in mediating hormonally responsive adenylate cyclase and cAMP-dependent protein kinase was examined in vivo and in vitro when pseudopregnant rats were injected with hCG. Intracellular ovarian levels of cAMP increased, as expected, but no change in cGMP concentrations was observed. However, both cGMP and cAMP activated ovarian CDPK holoenzyme in vitro but cGMP had a lower affinity. The subunits of hCG were without effect. Even though cGMP and cAMP dissociate partially purified ovarian CDPK holoenzyme in vitro, the receptor sites of the regulatory subunit of CDPK would appear to be relatively specific for cAMP. Moreover, cGMP probably does not mediate hCG action in vivo.
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PMID:Role of cyclic nucleotides in modulating ovarian hCG action. 20 12

Epinephrine rapidly activates phosphorylase in hepatocytes, mainly by a mechanism(s) involving alpha-adrenergic and not beta-adrenergic receptors. The alpha-adrenergic mechanism does not involve accumulation of cAMP or activation of cAMP-dependent protein kinase. It is impaired when hepatocytes are depleted of calcium by EGTA treatment and is rapidly restored by readdition of calcium. Basal phosphorylase is also lowered by calcium deficiency and rapidly increased by calcium but not other divalent cations. The divalent cation ioniphore A23187 increases phosphorylase a levels in hepatocytes in a calcium-dependent manner. Calcium deficiency does not modify the effects of glucagon, cAMP, or beta-adrenergic activation on phosphorylase. Activation of alpha-adrenergic receptors rapidly increases 45Ca fluxes in hepatocytes. Glucagon produces similar effects, but supraphysiological concentrations are required. The hypothesis is advanced that alpha-adrenergic activation of phosphorylase involves alterations in cell calcium such that there is an increase in cytosolic Ca2+ concentration leading to increased phosphorylase kinase activity. Epinephrine induces greater cAMP accumulation in calcium-depleted cells than in normal cells. The effect is mediated by alpha-adrenergic and not beta-adrenergic receptors. Calcium deficiency also cuases cAMP accumulation in hepatocytes incubated with phenylephrine but does not modify the responses of the cells to isoproterenol, glucagon, or cAMP. Low concentrations of calcium rapidly reverse alpha-adrenergic receptor-mediated cAMP accumulation in calcium-depleted cells. The hypothesis is advanced that calcium normally exerts an inhibitory effect on a linkage between alpha-adrenergic receptors and adenylate cyclase in hepatocytes.
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PMID:Mechanisms of catecholamine actions on liver carbohydrate metabolism. 20 89

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


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