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)

A protein kinase (EC 2.7.1.37) which phosphorylates histones was purified partially from the soluble fractions of cultured plant cells. The optimum pH was 7.5 to 9.0. The activity wasnot stimulated by exogeneous cyclic AMP. It was thermolabile and completely dependent on the presence of Mg2+ or Mn2+ for activity. p-Chloromercuribenzoate inactivated this enzyme and this inactivation was overcome by mercaptoethanol.
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PMID:Protein kinase in cultured plant cells. 0 Oct 89

The presence of activators(AMP and sulphate) or inhibitors(acetyl-CoA) has no influence on the Hill coefficient of the S-shaped [pyruvate]--velocity curve of either the pyruvate-NAD+ overall reaction(h equals 2.5) or that of the pyruvate-K3Fe(CN)6 ACTIVITY OF THE FIRST ENZYME (H EQUALs 1.3). pH STUDIES INDICATED THAT THE Hill coefficient is dependent on subunit ionization within the pyruvate-containing complex and not on those in the free complex. It is concluded that pyruvate conversion rather that pyruvate binding is responsible for the allosteric pattern. The activity is due to absence of a protein kinase, mainly regulated at the acetyl-CoA/CoA, and NADH/NAD+ levels and by the value of the energy charge.
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PMID:The pyruvate-dehydrogenase complex from Azotobacter vinelandii. 2. Regulation of the activity. 0 Dec 51

Calcium transport into sarcoplasmic reticulum fragments isolated from dog cardiac and mixed skeletal muscle (quadriceps) and from mixed fast (tibialis), pure fast (caudofemoralis) and pure slow (soleus) skeletal muscles from the cat was studied. Cyclic AMP-dependent protein kinase and phosphorylase b kinase stimulated the rate of calcium transport although some variability was observed. A specific protein kinase inhibitor prevented the effect of protein kinase but not of phosphorylase b kinase. The addition of cyclic AMP to the sarcoplasmic reticulum preparations in the absence of protein kinase had only a slight stimulatory effect despite the presence of endogenous protein kinase. Cyclic AMP-dependent protein kinase catalyzed the phosphorylation of several components present in the sarcoplasmic reticulum fragments; a 19000 to 21 000 dalton peak was phosphorylated with high specific activity in sarcoplasmic reticulum preparations isolated from heart and from slow skeletal muscle, but not from fast skeletal muscle. Phosphorylase b kinase phosphorylated a peak of molecular weight 95000 in all of the preparations. Cyclic AMP-dependent protein kinase-stimulated phosphorylation was optimum at pH 6.8; phosphorylase b kinase phosphorylation had a biphasic curve in cardiac and slow skeletal muscle with optima at pH 6.8 and 8.0. The addition of exogenous phosphorylase b kinase or protein kinase increased the endogenous level of phosphorylation 25-100%. All sarcoplasmic reticulum preparations contained varying amounts of adenylate cyclase, phosphorylase b and a (b:a = 30.1), "debrancher" enzyme and glycogen (0.3 mg/mg protein), as well as varying amounts of protein kinase and phosphorylase b kinase which were responsible for a significant endogenous phosphorylation. Thus, the two phosphorylating enzymes stimulated calcium uptake in the sarcoplasmic reticulum of a variety of muscles possessing different physiologic characteristics and different responses to drugs. In addition, the phosphorylation catalyzed by these enzymes occurred at two different protein moieties which make physiologic interpretation of the role of phosphorylation difficult. While the role phosphorylation in these mechanisms is complex, the presence of a glycogenolytic enzyme system may be an important link in this phenomenon. The sarcoplasmic reticulum represents a new substrate for phosphorylase b kinase.
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PMID:The rate of calcium uptake into sarcoplasmic reticulum of cardiac muscle and skeletal muscle. Effects of cyclic AMP-dependent protein kinase and phosphorylase b kinase. 0 25

The autophosphorylation of rabbit and human erythrocyte membranes has been studied under various experimental conditions. The phosphopeptides of the erythocyte membranes were identified using sodium dodecyl sulfate-polyacrylamide slab gel electrophoresis followed by ratioautography. The pattern of phosphorylatiion of membrane components differs with respect to the phosphoryl donor used (ATP or GTP) and to the pH at which the reaction is carried out. Both species appear to contain at least two distinct membrane-bound protein kinases. The human erythrocyte membrane contains a cyclic adenosine 3'5'-monophosphate (cyclic AMP)-dependent protein kinase and several substrates for this kinase. Only ATP can be used as a phosphoryl donor for this kinase. In contrast, the rabbit erythrocyte membrane does not contain a cyclic AMP dependent protein kinase but does contain a kinase which utilizes only ATP as the phosphoryl donor and is specific for certain endogenous substrates at low pH. Both the human and rabbit erythrocyte membranes contain a kinase which utilizes GTP, perhaps also ATP, as the phosphoryl donor. The substrates of these kinases are similar in both species.
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PMID:An analysis of the autophosphorylation of rabbit and human erythrocyte membranes. 0 93

1. Four fractions of protein kinase (EC 2.7.1.37) activity (Peak IH, IIH, IIIC and IVC) have been resolved and partially purified from the 100 000 X g supernatant fraction of bovine parotid glands by DEAE-cellulose and phosphocellulose chromatographies. 2. The protein kinases of Peak IH and IIH were adenosine 3',5'-monophosphate (cyclic AMP) -dependent and had similar enzymic properties. The enzyme activities of Peak IIIC and IVC were cyclic-AMP independent, but there were some distinct differences between their properties. The protein kinase in Peak IIIC was activated by 0.2 M NaCl or KCl and phosphorylated casein preferentially as the substrate, utilizing only ATP as a phosphate donor. On the other hand, the protein kinase in Peak IVC was inhibited by univalent salts and preferred phosvitin to casein, utilizing either ATP or GTP as a phosphate donor. 3. Tolbutamide increased the Km value for ATP and the dissociation constant for cyclic AMP, resulting in the inhibition of cyclic-AMP dependent protein kinase activity in the presence of cyclic AMP. Tolbtamide and its carboxy derivative, 1-butyl-3-p-carboxyphenylsulfonylurea, exerted almost no inhibitory effect on either the cyclic-AMP dependent protein kinase activities in the absence of cyclic AMP or on the cyclic-AMP independent protein kinase activities.
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PMID:Characterization of protein kinases from bovine parotid glands. The effect of tolbutamide and its derivative on these partially purified enzymes. 0 16

The kinetics of rat liver L-type pyruvate kinase (EC 2.7.1.40), phosphorylated with cyclic AMP-stimulated protein kinase from the same source, and the unphosphorylated enzyme have been compared. The effects of pH and various concentrations of substrates, Mg2+, K+ and modifiers were studied. In the absence of fructose 1, 6-diphosphate at pH 7.3, the phosphorylated pyruvate kinase appeared to have a lower affinity for phosphoenolpyruvate (K0.5=0.8 mM) than the unphosphorylated enzyme (K0.5=0.3 mM). The enzyme activity vs. phosphoenolpyruvate concentration curve was more sigmoidal for the phosphorylated enzyme with a Hill coefficient of 2.6 compared to 1.6 for the unphosphorylated enzyme. Fructose 1, 6-diphosphate increased the apparent affinity of both enzyme forms for phosphoenolpyruvate. At saturating concentrations of this activator, the kinetics of both enzyme forms were transformed to approximately the same hyperbolic curve, with a Hill coefficient of 1.0 and K0.5 of about 0.04 mM for phosphoenolpyruvate. The apparent affinity of the enzyme for fructose 1, 6-diphosphate was high at 0.2 mM phosphoenolpyruvate with a K0.5=0.06 muM for the unphosphorylated pyruvate kinase and 0.13 muM for the phosphorylated enzyme. However, in the presence of 0.5 mM alanine plus 1.5 mM ATP, a higher fructose 1, 6-diphosphate concentration was needed for activation, with K0.5 of 0.4 muM for the unphosphorylated enzyme and of 1.4 muM for the phosphorylated enzyme. The results obtained strongly indicate that phosphorylation of pyruvate kinase may also inhibit the enzyme in vivo. Such an inhibition should be important during gluconeogenesis.
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PMID:Comparative kinetic studies on the L-type pyruvate kinase from rat liver and the enzyme phosphorylated by cyclic 3', 5'-AMP-stimulated protein kinase. 0 27

Three protein kinases Ko, K1, and KII have been extracted from rat pancreas homogenate, Ko is not stimulated by cyclic AMP. K1 is poorly stimulated by cyclic AMP (1.3 times), Ku is highly stimulated (6 times). The specificity of KII with respect to various nucleotides and cyclic nucleotides has been determined. K1 and KII account for the total cyclic AMP dependent protein kinase activity in the homogenate.
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PMID:Purification and properties of cyclic AMP dependent and independent protein kinases from rat pancreas. 0 57

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

Sarcoplasmic reticulum fragments isolated from dog cardiac muscle possess a calcium-accumulating system associated with a series of enzymes linked to glycogenolysis. These enzymes include: adenylate cyclase, cyclic AMP-dependent protein kinase, phosphorylase b kinase, phosphorylase (b/a, 30/1),"debrancher" enzyme, and glycogen (0.3 to 0.7 mg/mg of protein). The sarcoplasmic reticulum preparation produced glucose 1-phosphate and glucose from either endogenous or exogenous glycogen. Both the calcium-accumulating and glycogenolytic enzymes sediment in a single peak at 33% sucrose on a linear continous sucrose density gradient, and the complex remains intact throughout repeated washing. Glycogen particles appear to be associated with the sarcoplasmic reticulum in situ as well as in the isolated microsomal fraction. The sarcoplasmic reticulum-glycogenolytic complex, monitored by a linked enzyme spectrophotometric assay, shows several features: (a) activation of phosphorylase activity to peak rate occurs over a very rapid time course which cannot be duplicated using combinations of purified enzymes; (b) activation is inhibited by protein kinase inhibitor; (c) phosphorylase b functions as in the purified form with respect to AMP (Km, 0.3 mM); (d) in the presence of limiting amounts of glycogen, optimal phosphorylase b activity in the sarcoplasmic reticulum requires the presence of debrancher, and the activity is sensitive to inhibitors of that enzyme such as Tris, which suggests the possiblity that the enzymes bear a specific structual relationship to the glycogen present. Phosphorylase b leads to a activation in the sarcoplasmic reticulum was completely resistant to ethylene glycol bis(beta-aminoethyl either)-N,N'-tetraacetic acid (EGTA). Inhibition of calcium accumulation by or release of bound calcium from sarcoplasmic reticulum by X537A (RO 2-2985) did not alter the EGTA resistance. These results suggest that cardiac sarcoplasmic reticulum is a complex organelle containing functions that may be related to excitation-contraction coupling and intermediary metabolism.
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PMID:Association of gylcogenolysis with cardiac sarcoplasmic reticulum. 0 55

Beta-Adrenergic stimulation of the ventral prostate cyclic-AMP system was investigated by examining the influence of isoproterenol on endogenous cyclic-AMP levels as well as on the activities of adenylate cyclase CEC 4.6.1.1) and cyclic-AMP-dependent and independent protein kinases (EC 2.7.1.37). Administration of isoproterenol (1 mg/kg, ip) resulted in rapid elevation of adenylate cyclase activity (119%) and cyclic-AMP levels (593%). The observed isoproterenol-stimulated changes in cyclic-AMP metabolism of the ventral prostate were time-dependent and maximal stimulation was seen 5 min after treatment with this beta-adrenergic agonist. The increases in prostatic adenylate cyclase and cyclic-AMP also were related to the dose of isoproterenol administered and maximal enhancement of these parameters was seen with 1 mg/kg dose of the agonist. Whereas pretreatment of rats with propranolol (3mg/kg, ip) partially reversed these alterations, administration of an alpha-adrenergic antagonist, phentolamine, even at a dose of 5 mg/kg, failed to elicit any appreciable effect. Stimulation of prostatic soluble protein kinase by isoproterenol was associated with a decrease (33%) in the activity of the cyclic-AMP-dependent protein kinase with a concomitant increase (25%) in that of the independent enzyme. Whereas the ability of the enzyme to bind cyclic-(3H) AMP in vitro was decreased (54%) following isoproterenol treatment, the protein kinase activity ratio (-cyclic-AMP/+cyclic AMP) was significantly elevated from 0.51+/0.05 to 0.95+/0.08. Although propranolol alone had little or no effect on these parameters, it inhibited partially the isoproterenol-induced alterations in cyclic-AMP-dependent protein kinase and the cyclic-AMP binding capacity. Treatment with propranolol also blocked the increases in the kinase activity ratio and in the activity of cyclic-AMP-independent enzyme seen with isoproterenol. Data suggest that the concentration of ventral prostate cyclic-AMP as well as the activities of adenylate cyclase and cyclic-AMP-dependent and independent form of protein kinases are subject to modulation by beta-adrenergic stimulation.
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PMID:Effects of isoproterenol on cyclic-AMP metabolism in rat ventral prostate. 0 2


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