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 effect of acidosis on cAMP-dependent protein kinase activity in perfused hearts from normal and reserpinized rats has been investigated. The results were compared to the effect of acidosis on myocardial contractility under the same conditions. The results showed that acidosis increases the cAMP-dependent protein kinase activity in normal hearts. This increase was abolished when the hearts were depleted of norepinephrine by previous treatment with reserpine. As regards myocardial contractility, there was a similar decrease by acidosis either in normal hearts with increased cAMP-dependent protein kinase activity or in reserpinized hearts in which the increase in protein kinase activity was prevented. Two alternative hypotheses are suggested: (1) a dissociation between contractility and cAMP levels, or (2) a "blockade" by acidosis of the mechanical effect of increasing cAMP-dependent protein kinase activity.
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PMID:Effect of acidosis on heart cAMP-dependent protein kinase. 8 Sep 85

A cAMP-dependent protein kinase has been isolated from rabbit muscle and purified. The affinity constant of the enzyme for the nucleotide is Ka = 9.3 X 10(-9) M, with a Vmax = 0.013 X 10(12) moles bound cAMP/1 microgram protein. The influence exerted by different factors is studied: a) Inhibitor (I) of kinase activity: increases the binding capacity for cAMP, by percentages which depend on the amount of I. In the presence of inhibitor (120 microgram/100 microliter) the affinity constant is Ka = 4.1 X 10(-9) M, without change in Vmax. b) Effect of pH: it has a complex influence over binding, being also regulated by cAMP concentration. The positive effect on binding of ionic and bovine serum albumin concentrations, and the negative effect of enzyme preincubation before additions of (H3) cAMP, have also been studied. The importance of these effectors to obtain a high degree of sensitivity in the binding protein method has been assertained.
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PMID:Binding activity regulation of rabbit skeletal muscle adenosine 3'-5'-monophosphate-dependent protein kinases. 8 84

The effects of histamine on heart cAMP-dependent protein kinase activity, cAMP levels, phosphorylase activity, and contractile force was investigated in the perfused guinea pig heart. To accurately determine the protein kinase activity ratio in guinea pig heart, it was necessary to measure kinase activity in whole homogenates immediately after homogenization of the tissue. Histamine produced a rapid dose-dependent increase in cAMP and the protein kinase activity ratio followed by increased in contractile force and phosphorylase activity. There was a good correlation between the degree of protein kinase activation and the increase in phosphorylase and force. The beta-adrenergic blocking agent propranolol did not reduce the effects of histamine, but metiamide, a potent H2-receptor antagonist, greatly attenuated all the effects of histamine. The data support the hypothesis that increases in heart cAMP-dependent protein kinase activity produce corresponding increases in contractile force and phosphorylase activity.
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PMID:Involvement of cAMP-dependent protein kinase in the regulation of heart contractile force. II. 8 6

We have examined the proteins secreted into the growth medium by normal and transformed cells. Transformed cell lines from several mammalian species all secrete proteins in the 58,000 dalton molecular weight range. These proteins are all immunologically related and are secreted at low levels or not at all by the parental normal cell lines. Secretion of the 58K proteins occurs with either DNA or RNA virus transformation and with spontaneous transformation. The transformed cells also secrete phosphoproteins in the same size range, but these are immunologically distinct from the 58K proteins mentioned above. The sizes of the phosphoproteins are species-specific and unrelated to the transforming virus. Incubation of conditioned media from transformed cell cultures with gamma-32P-ATP labels phosphoproteins of the same sizes, indicating the presence in the media of both protein kinase and substrate. All three properties (58K protein, phosphoprotein, in vitro phosphorylation) are closely correlated with transformation in cells transformed by temperature-sensitive viruses. The biological implications of these results remain unknown, but the results may be relevant to recent data on the (phospho)proteins and protein kinase encoded by RNA tumor viruses and the molecular basis of the transformed phenotype.
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PMID:Transformed mammalian cells secrete specific proteins and phosphoproteins. 8 65

The inhibition of cell replication in two human carcinoma cell lines by various cyclic AMP analogs was explored. In all instances, the addition of the cyclic nucleotide phosphodiesterase inhibitor 1-methyl-3-isoburylxanthine resulted in synergistic growth inhibition by the analogs. A correlation was found between an analog's ability to inhibit growth and its ability to activate protein kinase. A differential effect of the breakdown product 8-bromo-AMP (8-BrAMP) on cell replication in the two cell lines was observed; i.e., one cell type was extremely sensitive to inhibition by 8-BrAMP and the growth inhibition could not be reversed by uridine, whereas the other cell type was less sensitive to 8-BrAMP and the growth inhibition was significantly reversed by uridine.
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PMID:Differential growth inhibition in two human carcinoma cell lines by cyclic adenosine 5'-monophosphate analogs. 9 Jan 51

(-)-trans-delta 1-Tetrahydrocannabinol (delta 1-THC) antagonized the cyclic AMP responses of WI-38 fibroblasts to both prostaglandin E1 (PGE1) and catecholamines. Both cellular cyclic AMP accumulation and cyclic AMP escape to the incubation medium were reduced, but the reduction of escape was much more dramatic at all concentrations of the drug. Conversely, long term incubations of cells with delta 1-THC alone resulted in substantial accumulations of cyclic AMP in the incubation medium. This effect was potentiated by the phosphodiesterase inhibitor 1-methyl, 3-isobutylxanthine and appeared to result from weak agonist activity of the cannabinoid as determined by a) stimulation of radioactivity incorporated into cyclic AMP using 3H-adenine prelabelled cells, and b) a rapid and pronounced increase in the activity ratio of cellular protein kinase. The antagonistic effect of delta 1-THC on the cellular response to PGE1 was greater in preconfluent cells than in confluent monolayers. Further, the increased sensitivity of preconfluent cultures to delta 1-THC was associated with the appearance of cytoplasmic vacuoles in the perinuclear region of the cells. Cannabidiol acted similar to delta 1-Thc in affecting cyclic AMP metabolis whereas cannabinol and cannabicyclol showed mixed effects on the various parameters studied.
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PMID:Effects of delta 1-tetrahydrocannabinol on cyclic AMP in cultured human diploid fibroblasts. 9 29

It has been shown that the activity of Ca(2+)-ATPase increases during development. Epinephrine in vivo increases the activity of Ca(2+)-ATPase in chick skeletal muscles. The effect of hormone is lacking at embryonic stages of development and appears only before hatching. In the presence of exogenous protein kinase, cAMP also increases the activity of the enzyme, this effect being observed also in embryonic muscles. Lack of effect of epinephrine on Ca(2+)-ATPase in embryonic muscles is associated with non-reactivity of their adenylate cyclase to catecholamines. Ca(2+)-ATPase itself already at embryonic period is ready to react to cAMP. It is concluded that Ca(2+)-ATPase of sarcoplasmic reticulum is one of the sites of action of catecholamines on calcium metabolism in muscle cell and that this action is realized via the system adenylate cyclase-cAMP-protein kinase.
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PMID:[The effect of catecholamines on the Ca2(+)-adenosinetriphosphatase of the sarcoplasmic reticulum in the skeletal muscles in chicken ontogeny]. 9 34

Phosphorylase b kinase from rabbit muscle phosphorylates glycogen synthase purified from the same tissue. The reaction is markedly stimulated by Ca2+ and results in a decrease in the synthase %I activity. Phosphorylase b kinase action leads to the incorporation of phosphate (0.6 to 0.8 mol/mol of subunit) preferentially into a single cyanogen bromide fragment of synthase (fragment III). Cyclic AMP-independent synthase kinase also shows a specificity for the site(s) contained in fragment III whereas the cyclic AMP-dependent protein kinase exerts a preference for the site(s) located in a distinct cyanogen bromide fragment (fragment II). A Ca2+-stimulated endogenous kinase also results in the phosphorylation of fragment III and can be attributed to the presence of phosphorylase b kinase. The finding of a Ca2+-stimulated phosphorylation of glycogen synthase has important implications for the regulation of glycogen metabolism and particularly those processes thought to be controlled by cytoplasmic Ca2+ concentration.
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PMID:Ca2+-stimulated phosphorylation of muscle glycogen synthase by phosphorylase b kinase. 10 68

Phosphorylation of skeletal muscle glycogen synthase catalyzed by a protein kinase is stimulated up to 10-fold by the calcium-dependent regulator (CDR) protein. Half-maximal stimulation requires about 1 microgram of CDR/ml. Phosphorylation by the CDR-dependent synthase kinase is more rapid at pH 8.6 than at pH 6.8 and is blocked by ethylene glycol bis(beta-aminoethyl-ether)N,N'-tetraacetic acid and trifuloperazine. Approximately 60 to 70% of the phosphate is incorporated into the trypsin-insensitive region of glycogen synthase resulting in conversion of the a form to the b form of the enzyme. The CDR-dependent synthase kinase is not myosin light chain kinase, as this enzyme does not phosphorylate glycogen synthase. Furthermore, synthase phosphorylation by the cAMP-dependent protein kinase catalytic subunit is not affected by CDR. The possibility that CDR-dependent synthase kinase may be phosphorylase kinase is being investigated.
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PMID:Stimulation of glycogen synthase phosphorylation by calcium-dependent regulator protein. 10 93

Several in vitro properties of partially purified form II RNA polymerase from Drosophila melanogaster embryo nuclei are described. The enzyme preparation is free from contaminating RNase, protein kinase, and polyphosphate kinase activities and can be used to study the incorporation of gamma-32P-labeled nucleoside triphosphates. The enzyme exhibits a biphasic heat inactivation pattern which is probably related to differential lability of its two subforms. However, a considerable protection against heat inactivation is provided by the nucleoside triphosphates present in the in vitro reaction system such that the enzyme catalyzes RNA synthesis in a nearly linear mode for over 2 hr at 30 C. Two initiation inhibitors, rifamycin AF/013 was found unsuitable for critical studies because of the high concentrations necessary for total inhibition (200 micrograms/ml) and particularly because of the obligate use of solvents which secondarily have a destabilizing effect on native DNA. Poly[I] was found to effectively block initiation at very low concentrations (1 microgram/ml). The enzyme rapidly forms poly[I]-resistant preinitiation complexes on both double- and single-stranded DNA. These complexes decay with a half-life of 2.5--3 min. RNA synthesis from poly[I]-resistant complexes amounts to 10% of the total potential synthesis on both double- and single-stranded DNA. Enzyme-DNA saturation experiments indicate that the form II enzyme discriminates two types of sites on Drosophila DNA, tight binding and weak binding, from which RNA synthesis proceeds slowly and rapidly, respectively. The tight-binding sites appear to be analogous to those sites with which the enzyme is able to form poly[I]-resistant complexes.
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PMID:Form II DNA-dependent RNA polymerase from Drosophila melanogaster: general in vitro catalytic properties and template interactions. 11 Mar 17


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