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)

Two rabbit erythrocyte casein kinases, GTP:casein kinase I and GTP:casein kinase II, have been purified 29 000- and 47 000-fold, respectively. Studies employing sucrose density gradient centrifugation indicate that kinase I has a molecular weight of about 9.5 - 10(5) (25 S) and kinase II about 1.4 - 10(6) (32 S). These enzymes can utilize either ATP or GTP as the phosphoryl donor. Among various protein substrates examined, these kinases catalyze the phosphorylation of casein greater than 50% dephosphorylated phosvitin congruent to 50% dephosphorylated casein greater than phosvitin. Histones, protamine and bovine serum albumin are poor phosphoryl acceptors. Kinetic data indicate that both enzymes are inhibited by high casein substrate concentrations which may be partially relieved by NaCl. Both phosphotransferases require Mg(2+) for activity and are optimally active at pH 9.0. The enzymes have apparent Km values of 2.5 - 10(-5) M for GTP, 2 - 10(-5) M for ATP, and 0.4--0.6 mg/ml for casein. The incorporation of the terminal phosphate of GTP into casein as catalyzed by these enzymes is inhibited to varying degrees by ATP, ITP, ADP, and GDP but not by UTP, CTP, GMP, adenosine 3':5'-cyclic monophosphate, and guanosine 3':5'-cyclic monophosphate. In addition, NaF and 2,3-diphosphoglyceric acid are also found to inhibit the activity of both kinases. The effect of 2,3-diphosphoglycerate is interesting and suggests that this metabolite may regulate the activity of the casein kinases in the red blood cells.
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PMID:Multiple forms of casein kinase from rabbit erythrocytes. 0 76

Three protein kinases (EC 2.7.1.37) were detected in Blepharisma and partially purified. The enzymes were most active with histone as substrate protein. The stability of the bond between phosphate and protein acceptor showed the characteristics of seryl- or threonylphosphate. Protein kinase I was solubilized by ultrasonication or freezing and thawing, while the enzymes II and III were readily solubilized by mild homogenization. Protein II and III were noticeably activated by cAMP and cGMP, while protein kinase I was inhibited by cAMP. Associated with protein kinase II and III activity was the ability to bind labeled cAMP. The following molecular weights were determined: 90000 for enzyme I, 280000 for enzyme II, and 95000 for enzyme III. Various apparent Michaelis constants were estimated.
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PMID:Characterization of protein kinases from Blepharisma intermedium. 0 34

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 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

The protein kinase associated with virions of frog virus 3 was purified to apparent homogeneity by ion exchange chromatography and gel filtration. The enzyme protein appeared as a single polypeptide of molecular weight 50,000 to 55,000 as determined by gel filtration, glycerol gradient sedimentation, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and comprised approximately 0.4% of the total virion protein. The activity was classified as a cyclic nucleotide-independent protein kinase as it was not effected by cyclic adenosine 3':5'-monophosphate, cyclic guanosine 3':5'-monophosphate, or inhibited by a cyclic nucleotide-dependent protein kinase inhibitor protein, and utilized GTP as well as ATP as a phosphate donor. The greatest rates of phosphorylation were obtained with acidic phosphoprotein substrates such as casein or phosvitin, although potential physiological substrates for this activity included specific virion polypeptides of frog virus.
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PMID:Purification and properties of a virion protein kinase. 0 56

1. A cyclic 3',5'-AMP-independent protein kinase (ATP : protein phosphotransferase, EC 2.7.1.37) from rat liver cytosol was partially purified and characterized. Purification by (NH4)2SO4 precipitation, DEAE-cellulose, Bio Gel A-0.5 m and cellulose phosphate chromatography increased the specific activity about 700-fold. 2. An endogenous protein substrate was closely associated with the protein kinase and was not separable from this enzyme up to the cellulose phosphate stage. After phosphorylation, chromatography with Bio Gel A-0.5 m partially separated this endogenous phosphoprotein from the enzyme activity; this dissociation had no apparent effect on kinase activity with casein or phosvitin as substrates, or on the apparent molecular weight of the enzyme (approx. 158,000). 3. This protein kinase with casein, phosvitin, or the endogenous substrate was totally insensitive to the thiol reagents, p-hydroxymercuribenzoate, 5,5'-dithiobis(2-nitrobenzoic acid), iodoacetamide, and N-ethylmaleimide. The enzyme was also unaffected by cyclic 3',5'-AMP, heat-stable protein kinase inhibitor, and the regulatory subunit of a cyclic 3',5'-AMP-dependent protein kinase.
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PMID:Partial purification and properties of a cyclic 3',5'-AMP-independent protein kinase from rat liver. 1 21

The phosphorylation of pig liver pyruvate kinase by cyclic adenosine 3':5'-monophosphate-dependent protein kinase has been studied. For comparison, mixed histone and a synthetic heptapeptide were also used as substrates. Protein kinase was purified by chromatography on DEAE-cellulose, hydroxyapatite, and Sephadex G-200. The enzyme was stimulated by cyclic AMP with apparent Ka values of 2.5 and 0.8 x 10-7 M for pyruvate kinase and histone substrates, respectively. Divalent cations were essential for the activity of the protein kinase. Variation of the concentration of ATP resulted in approximately straight lines in Lineweaver-Burk plots for the phosphorylation of both pyruvate kinase and mixed histone. The apparent Km values for ATP were 21 and 11 muM, respectively. The phosphorylation rate increased with the concentration of pyruvate kinase even at a concentration of 2 muM pyruvate kinase. At a high ionic strength, the phosphorylation rate of both pyruvate kinase and histone decreased. The phosphorylation rate varied markedly with pH in imidazole/HC1 and Tris/HC1 buffers. At slightly alkaline pH values, pyruvate kinase was phosphorylated at a much higher rate than pH7, but this was not the case for histone. At pH 8.5, the phosphorylation rate of pyruvate kinase was 3.5 times the rate at pH 7, while the corresponding increase for the histone phosphorylation was 50 per cent. In potassium phosphate buffers, the phosphorylation rate of both substrates did not change significantly over the pH range studied. Arrhenius' plots of the protein kinase reaction resulted in a break at about 10 degrees when pyruvate kinase was used as substrate, whereas a straight line was obtained when using histone. The negative allosteric effectors of pyruvate kinase, alanine, and phenylalanine, increased the phosphorylation rate of pyruvate kinase at pH 8 by 50 and 120 per cent, respectively. The same effectors did not influence the phosphorylation rate of mixed histone or a synthetic heptapeptide. It is concluded that the conformations adopted by pyruvate kinase in the presence of allosteric inhibitors make it a better substrate for the protein kinase.
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PMID:Studies on the cyclic 3':5'-AMP-stimulated pig liver protein kinase reaction with pyruvate kinase as substrate. 1 74

This paper reports on the discovery of a protein kinase activity associated with the inner membrane of mammalian mitochondria. The enzyme does not respond to addition of cyclic AMP or cyclic GMP and has a preference for whole histone as phosphate acceptor. Some standard assay systems for the cyclic nucleotide-dependent cytosol protein kinases would be unable to pick up this activity of the orthophosphate concentration is higher than 25 mM and the pH or the assay lower than pH 6.5. The enzyme described here has an apparent pH optimum of 8.5. Activity in liver mitochondria is not evident unless the mitochondria are disrupted by either sonication or freezing and thawing. Distribution of kinase activity in centrifugal fractions of both liver and heart mitochondrial sonicates was parallel to that of the two inner membrane marker enzymes succinic dehydrogenase and cytochrome oxidase and quite different from that of the matrix enzyme malic dehydrogenase. Experiments with preparations enriched in outer or inner membranes confirmed the contention that this enzyme is located on the inner membrane. Since disruption of the inner membrane by a freeze-thaw treatment (after the outer membrane had been disrupted by swelling in phosphate) was necessary for full expression of activity by this enzyme, the tentative conclusion was reached that substrate is accepted only from the matrix side of the inner membrane.
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PMID:Protein kinase activity at the inner membrane of mammalian mitochondria. 1 32

The purpose of this investigation was to characterize the phosphorylation of bovine cardiac troponin by cyclic AMP-dependent protein kinase. The purified troponin-tropomyosin complex from beef heart contained 0.78 +/- 0.15 mol of phosphate per mol of protein. Analysis of the isolated protein components indicated that the endogenous phosphate was predominately in the inhibitory subunit (TN-I) and the tropomyosin-binding subunit (TN-T) of troponin. When cardiac troponin or the troponin-tropomyosin complex was incubated with cyclic AMP-dependent protein kinase and [gamma-32P]ATP, the rate of phosphorylation was stimulated by cyclic AMP and inhibited by the heat-stable protein inhibitor of cyclic AMP-dependent protein kinase. The 32P was incorporated specifically into the TN-I subunit with a maximal incorporation of 1 mol of phosphate per mol of protein. The maximal amount of phosphate incorporated did not vary significantly between troponin preparations that contained low or high amounts of endogenous phosphate. The Vmax of the initial rates of phosphorylation with troponin or troponin-tropomyosin as substrates was 3.5-fold greater than the value obtained with unfractionated histones. The rate or extent of phosphorylation was not altered by actin in the presence or absence of Ca2+. The maximal rate of phosphorylation occurred between pH 8.5 and 9.0. At pH 6.0 and 7.0 the maximal rates of phosphorylation were 13 and 45% of that observed at pH 8.5, respectively. These results indicate that cyclic AMP formation in cardiac muscle may be associated with the rapid and specific phosphorylation of the TN-I subunit of troponin. The presence of endogenous phosphate in TN-T and TN-I suggests that kinases other than cyclic AMP-dependent protein kinase may also phosphorylate troponin in vivo.
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PMID:Phosphorylation of cardiac troponin by cyclic adenosine 3':5'-monophosphate-dependent protein kinase. 1 36


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