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:2.7.11.1 (protein kinase)
81,284 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The tyrosine-3-monooxygenase activity [L-tyrosine, tetrahydropteridine: oxygen oxidoreductase (3-hydroxylating); EC 1.14.16.2] of rat adrenal medulla is induced 20-24 hr after the injection of reserpine (16 mumol/kg intraperitoneally). This and other inducing stimuli increase the 3': 5'-cyclic AMP (cAMP) content in the medulla for longer than 60 min and activate the cAMP-dependent protein kinase (ATP: protein phosphotransferase; EC 2.7.1.37) for several hours. Corticotropin (ACTH), dopamine, and propranolol do not induce the monooxygenase, but elicit an increase in the cAMP content of the medulla which fails to activate protein kinase and lasts less than 1 hr. A high- and low-molecular-weight protein kinase are separated by gel filtration from the 20,000 X g pellet extract of adrenal medulla homogenate. The activity of the low-molecular-weight enzyme is expressed as its ability to phosphorylate histone. The protein kinase activity of the pellet is increased between 3 and 17 hr after reserpine injection. Our evidence indicates that this increase is due to a translocation from cytosol to subcellular structures of a kinase that utilizes lysine-rich histone as phosphate acceptor. The protein kinase activity that is extracted from a purified nuclear fraction prepared from the adrenal medulla of rats injected 7 hr previously with reserpine is greater than that extracted from medulla of saline-treated rats.
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PMID:Activation and nuclear translocation of protein kinase during transsynaptic induction of tyrosine 3-monooxygenase. 0 93

Hormone-sensitive lipase and cholesterol ester hydrolase of chicken adipose tissue were markedly activated by adenosine 3':5'-monophosphate (cAMP)-dependent protein kinase (on the average, 235 to 275%; occasionally as much as 1000%). Diglyceride and monoglyceride hydrolases were also activated, but to a lesser extent (60 to 87%). The activation of all four hydrolases was inhibited by protein kinase inhibitor and reversed by the addition of exogenous protein kinase. Following activation by cAMP-dependent protein kinase, all four hydrolases were deactivated in a Mg2+-dependent reaction and then reactivated to or near initial levels on incubation with cAMP and Mg2+-ATP. The reversible deactivation is assumed to reflect activity of one or more protein phosphatases. The maximum activation obtainable for the four hydrolases decreased when the tissue had been previously exposed to glucagon, indicating that the glucagon-induced activation was probably similar to or identical with the activation demonstrated in cell-free preparations. The pH optima for the four hydrolase activities were similar (7.13 to 7.38). Although the absolute activities and relative degrees of kinase activation differed according to the particular emulsified substrates used, the results do not rule out the possibility that all four hydrolase activities are referable to a single hormone-sensitive hydrolase. Hormone-sensitive acyl hydrolases were separated from lipoprotein lipase by heparin-Sepharose affinity chromatography. Lipoprotein lipase was active against triolein, diolein, and monoolein, but not cholesterol oleate. Incubation of lipoprotein lipase with exogenous protein kinase, cAMP, and Mg2+ATP had no effect on any of the three hydrolase activities. Lipoprotein lipase was further purified to homogeneity and used to prepare antiserum in rabbits. The immunoglobin G fraction from these antisera completely inhibited lipoprotein lipase eluted from heparin-Sepharose columns. However, the hormone-sensitive hydrolase activities (not retained on heparin-Sepharose affinity chromatography) were not inhibited by anti-lipoprotein lipase immunoglobin G, and anti-lopoprotein lipase immunoglobin G did not affect the activation process in crude fractions. Thus, hormone-sensitive lipase and lipoprotein lipase, functionally distinct enzymes, have been physically resolved and immunochemically distinguished. Apparently lipoprotein lipase activity is not regulated, at least directly, by cAMP-dependent protein kinase.
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PMID:Triglyceride, diglyceride, monoglyceride, and cholesterol ester hydrolases in chicken adipose tissue activated by adenosine 3':5'-Monophosphate-dependent protein kinase. Chromatographic resolution and immunochemical differentiation from lipoprotein lipase. 0 45

Dibutyryl cyclic AMP (dB-cAMP) elicits a concentration-dependent stimulation of tyrosine hydroxylase activity in the striatal and mesolimbic synaptosomes. The per cent of stimulation is significantly higher in the mesolimbic synaptosomes than in the striatal synaptosomes. dB-cAMP and depolarizing agents (ouabain or veratridine) have an additive effect on synaptosomal tyrosine hydroxylase activity, indicating that they stimulate tyrosine hydroxylase activity by different mechanisms. cAMP does not stimulate soluble striatal tyrosine hydroxylase activity unless it is added in combination with ATP and Mg2+, compounds required for the activity of cAMP-dependent protein kinase. The cAMP elicited per cent stimulation of soluble tyrosine hydroxylase activity is dependent upon the concentration of added protein kinase and upon the pH of the reaction. dB-cAMP has the same effect on the kinetic state of tyrosine hydroxylase in synaptosomes as cAMP on the soluble tyrosine hydroxylase. The nucleotide does not alter the apparent Km for tyrosine, reduces the Km for the pteridine cofactor and increases the Ki for dopamine. Thus, cAMP increases the affinity of tyrosine hydroxylase for the pteridine cofactor and concomitantly decreases the affinity for the end-product inhibition.
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PMID:Stimulation of tyrosine hydroxylase activity by cyclic AMP in synaptosomes and in soluble striatal enzyme preparations. 0 24

The effects of the alpha-adrenergic agonist phenylephrine on the levels of adenosine 3':5'-monophosphate (cAMP) and the activity of the cAMP-dependent protein kinase in isolated rat liver parenchymal cells were studied. Cyclic AMP was very slightly (5 to 13%) increased in cells incubated with phenylephrine at a concentration (10(-5) M) which was maximally effective on glycogenolysis and gluconeogenesis. However, the increase was significant only at 5 min. Cyclic AMP levels with 10(-5) M phenylephrine measured at this time were reduced by the beta-adrenergic antagonist propranolol, but were unaffected by the alpha-blocker phenoxybenzamine, indicating that the elevation was due to weak beta activity of the agonist. When doses of glucagon, epinephrine, and phenylephrine which produced the same stimulation of glycogenolysis or gluconeogenesis were added to the same batches of cells, there were marked rises in cAMP with glucagon, minimal increases with epinephrine, and little or no changes with phenylephrine, indicating that the two catecholamine stimulated these processes largely by mechanisms not involving cAMP accumulation. DEAE-cellulose chromatography of homogenates of liver cells revealed two major peaks of cAMP-dependent protein kinase activity. These eluted at similar salt concentrations as the type I and II isozymes from rat heart. Optimal conditions for preservation of hormone effects on the activity of the enzyme in the cells were determined. High concentrations of phenylephrine (10(-5) M and 10(-4) M) produced a small increase (10 tp 16%) in the activity ratio (-cAMP/+cAMP) of the enzyme. This was abolished by propranolol, but not by phenoxybenzamine, indicating that it was due to weak beta activity of the agonist. The increase in the activity ratio of the kinase with 10(-5) M phenylephrine was much smaller than that produced by a glycogenolytically equivalent dose of glucagon. The changes in protein kinase induced by phenylephrine and the blockers and by glucagon were thus consistent with those in cAMP. Theophylline and 1-methyl-3-isobutylxanthine, which inhibit cAMP phosphodiesterase, potentiated the effects of phenylephrine on glycogenolysis and gluconeogenesis. The potentiations were blocked by phenoxybenzamine, but not by propranolol. Methylisobutylxanthine increased the levels of cAMP and enhanced the activation of protein kinase in cells incubated with phenylephrine. These effects were diminished or abolished by propanolol, but were unaffected by phenoxybenzamine. It is concluded from these data that alpha-adrenergic activation of glycogenolysis and gluconeogenesis in isolated rat liver parenchymal cells occurs by mechanisms not involving an increase in total cellular cAMP or activation of the cAMP-dependent protein kinase. The results also show that phosphodiesterase inhibitors potentiate alpha-adrenergic actions in hepatocytes mainly by a mechanism(s) not involving a rise in cAMP.
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PMID:Studies on the alpha-andrenergic activation of hepatic glucose output. II. Investigation of the roles of adenosine 3':5'-monophosphate and adenosine 3':5'-monophosphate-dependent protein kinase in the actions of phenylephrine in isolated hepatocytes. 0 57

In rabbit heart homogenates about 50% of the cAMP-dependent protein kinase activity was associated with the low speed particulate fraction. In homogenates of rat or beef heart this fraction represented approximately 30% of the activity. The percentage of the enzyme in the particulate fraction was not appreciably affected either by preparing more dilute homogenates or by aging homogenates for up to 2 h before centrifugation. The particulate enzyme was not solubilized at physiological ionic strength or by the presence of exogenous proteins during homogenization. However, the holoenzyme or regulatory subunit could be solubilized either by Triton X-100, high pH, or trypsin treatment. In hearts of all species studied, the particulate-bound protein kinase was mainly or entirely the type II isozyme, suggesting isozyme compartmentalization. In rabbit hearts perfused in the absence of hormones and homogenized in the presence of 0.25 M NaCl, at least 50% of the cAMP in homogenates was associated with the particulate fraction. Omitting NaCl reduced the amount of particulate-bound cAMP. Most of the particulate-bound cAMP was probably associated with the regulatory subunit in this fraction since approximately 70% of the bound nucleotide was solubilized by addition of homogeneous catalytic subunit to the particulate fraction. The amount of cAMP in the particulate fraction (0.16 nmol/g of tissue) was approximately one-half the amount of the regulatory subunit monomer (0.31 nmol/g of tissue) in this fraction. The calculated amount of catalytic subunit in the particulate fraction was 0.18 nmol/g of tissue. Either epinephrine alone or epinephrine plus 1-methyl-3-isobutylxanthine increased the cAMP content of the particulate and supernatant fractions. The cAMP level was increased more in the supernatant fraction, possibly because the cAMP level became saturating for the regulatory subunit in the particulate fraction. The increase in cAMP was associated with translocation of a large percentage of the catalytic subunit activity from the particulate to the supernatant fraction. The distribution of the regulatory subunit of the enzyme was not significantly affected by this treatment. The catalytic subunit translocation could be mimicked by addition of cAMP to homogenates before centrifugation. The data suggest that the regulatory subunit of the protein kinase, at least that of isozyme II, is bound to particulate material, and theactive catalytic subunit is released by formation of the regulatory subunit-cAMP complex when the tissue cAMP concentration is elevated. A model for compartmentalized hormonal control is presented.
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PMID:Compartmentalization of adenosine 3':5'-monophosphate and adenosine 3':5'-monophosphate-dependent protein kinase in heart tissue. 1 21

Reproducible induction of the enzyme tyrosine aminotransferase by dibutyryl cAMP (Bt2cAMP) in a line of HTC hepatoma cells in suspension culture requires that the cells be preinduced with dexamethasone, a synthetic glucocorticoid which itself induces tyrosine aminotransferase. Concentrations of dexamethasone that do not induce tyrosine aminotransferase fail to support Bt2cAMP induction, removal of the steroid from the medium leads to a loss of the Bt2cAMP effect, and an HTC cell line whose aminotransferase is not steroid-inducible does not respond to the cyclic nucleotide. We show that the further induction of tyrosine aminotransferase by Bt2cAMP in dexamethasone-treated cells is due to an increased rate of enzyme synthesis. The cyclic nucleotide has no effect on aminotransferase synthesis in cells grown in the absence of steroid. Several lines of evidence suggest that dexamethasone acts at a step beyond the activation of protein kinase by cAMP: (a) basal levels of cAMP are not altered by growth of HTC cells in dexamethasone; (b) accumulation of cAMP from the medium is not enhanced; (c) the glucocorticoid does not induce cAMP-dependent protein kinase in HTC cells; and (d) there is no augmentation of cAMP binding to the regulatory protein, nor is there any change in cAMP activation of protein kinase caused by growth in dexamethasone. These results help define a system that should be useful in studying the interaction of cyclic nucleotides and steroid hormones.
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PMID:Interaction of glucocorticoid hormones and cyclic nucleotides in induction of tyrosine aminotransferase in cultured hepatoma cells. 1 22

We have studied the effects of adenosine 3':5'-monophosphate (cAMP)-dependent protein kinase on the phosphorylative and functional modification of bovine adrenal tyrosine hydroxylase. Incubation of partially purified tyrosine hydroxylase with cAMP-dependent protein kinase in the presence of [gamma32P]ATP and 5 micron cAMP led to a 3- to 5-fold activation of tyrosine hydroxylase and to incorporation of [32P]phosphate into protein. When tyrosine hydroxylase preparations activated by exposure to enzymatic phosphorylating conditions were analyzed by sucrose density gradient centrifugation, polyacrylamide gel electrophoresis, and gel electrofocusing, the radioactivity of 32P was coincident with the activity of tyrosine hydroxylase, suggesting incorporation of 32P from [gamma-32P]ATP into tyrosine hydroxylase. Polyacrylamide gel electrophoresis of the phosphorylated tyrosine hydroxylase preparation in the presence of 0.1% sodium dodecyl sulfate revealed that the 60,000-dalton polypeptide subunit of tyrosine hydroxylase served as the phosphate acceptor.
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PMID:In vitro phosphorylation of bovine adrenal tyrosine hydroxylase by adenosine 3':5'-monophosphate-dependent protein kinase. 3 70

A protein kinase (ATP:protein phosphotransferase, EC 2.7.1.37) which catalyzes the phosphorylation of troponin T, phosvitin and casein has been purified over 2000 fold from rabbit skeletal muscle. The partial purification of this new enzyme, designated troponin T kinase, involves precipitation of contaminating proteins at pH 6.1, fractionation of the supernatant with (NH4)2SO4 and successive column chromatographies on DEAE-cellulose, hydroxyapatite and Sepharose 6B. The chromatographic patterns on DEAE-cellulose and hydroxyapatite columns show two peaks of troponin T kinase activity. Gel filtration experiments indicate the existence of multiple, possibly aggregated, forms of the enzyme. The purified enzyme does not catalyze the phosphorylation of phosphorylase b, troponin I, troponin C, tropomyosin, protamine, or myosin light chain 2 nor does it catalyze the interconversion of glycogen synthase I into the D form. Troponin T kinase is not affected by the addition of cyclic nucleotides or AMP to the reaction mixture. Divalent cations (other than Mg2+, required for the reaction) do not stimulate the enzyme, and several are inhibitory. Other characteristics of the reaction catalyzed by troponin T kinase, such as Km values for ATP and substrate proteins, pH optima, effect of the concentration of Mg2+, substitution of ATP for GTP have also been studied.
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PMID:Purification and properties of troponin T kinase from rabbit skeletal muscle. 3 14

We have studied the effect of protein phosphokinase (EC 2.7.1.37; ATP:protein phosphotransferase) and phosphoprotein phosphatase (EC 3.1.3.16; phosphoprotein phosphohydrolase) on reverse transcriptase (RNA-dependent DNA nucleotidyltransferase) activity of Rous sarcoma virus. Protein kinase from Rous sarcoma virus-transformed chick embryo fibroblasts was purified by DEAE-cellulose chromatography, Sephadex gel filtration, and isoelectric focusing. Purified reverse transcriptase from Rouse sarcoma virus was preincubated with protein kinase and ATP under conditions allowing incorporation of phosphate into substrate protein. After the preincubation, reverse transcriptase activity was assayed in the presence of poly(rA).oligo(dT) as template. A 2- to 5-fold increase of reverse transcriptase activity was found after the preincubation of reverse transcriptase with protein kinase and ATP. Incubation of reverse transcriptase with heat-treated, inactive protein kinase and ATP had no effect on transcriptase activity. When the transcriptase preparation was incubated with protein kinase and [gamma-32P]ATP and subsequently purified by chromatography on phosphocellulose and Sephadex gel filtration, significant amounts of 32P-labeled proteins were found in the fractions exhibiting reverse transcriptase activity, suggesting 32P incorporation into transcriptase or transcriptase-associated proteins. A 20-60% decrease of reverse transcriptase activity was observed after incubation of reverse transcriptase with phosphatase. The results suggest that phosphorylative modification of reverse transcriptase may be critical in the regulation of reverse transcriptase-catalyzed DNA synthesis.
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PMID:Protein kinase and its regulatory effect on reverse transcriptase activity of Rous sarcoma virus. 5 72

Immunization of guinea pigs with bovine cardiac cAMP-dependent protein kinase (ATP:protein phosphotransferase, EC 2.7.1.37) resulted in the development of precipitating antibodies to the cAMP-binding subunit of the enzyme. Both the phosphorylated and nonphosphorylated cAMP-binding protein of the protein kinase reacted with the antiserum. A radioimmunoassay was developed that detects 10 ng of holoenzyme and permits measurement of enzyme concentrations in bovine cardiac muscle. Bovine liver, kidney, brain, and skeletal muscle contain protein kinases which are immunologically identical to those found in bovine cardiac muscle. However, the proportion of immuno-reactive enzyme activity differed for each tissue. All of the immunologically nonreactive enzyme in skeletal muscle and heart was separable from immunoreactive enzyme by chromatography on DEAE-cellulose. Rat tissues and pig heart contained protein kinase activity that crossreacted immunologically in a nonparallel fashion with bovine cardiac enzyme. These results indicate that cAMP-dependent protein kinases within and between species are immunologically heterogeneous.
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PMID:Radioimmunoassay of bovine heart protein kinase. 5 18


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