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)

Addition of acetate to a stationary phase culture of Escherichia coli in glycerol mineral salts medium containing phosphorus-32-labeled orthophosphate results in rapid loss of isocitrate dehydrogenase activity and concomitant incorporation of phosphorus-32 into the enzyme. This is the first example of protein phosphorylation in a bacterium in which the endogenous substrate for the protein kinase has been identified.
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PMID:Phosphorylation of Isocitrate dehydrogenase of Escherichia coli. 3 15

Polyphosphate kinase, an enzyme which incorporated the gamma-phosphate of ATP into long-chain polyphosphate molecules, was purified more than 700-fold from Arthrobacter atrocyaneus by ammonium sulphate fractionation, DEAE-cellulose column chromatography and Ssphadex G-200 gel filtration. The enzyme had a broad pH optimum at 6-0 to 7-0 and required Mn2+ or Mg2+, histone, and inorganic phosphate for activity. The Km for Mn-ATP was 0-53 mM, and for inorganic phosphate was 1-67 mM. Free ATP concentrations greater than 8 muM inhibited the enzyme. Free Mn2+ or Mg2+ concentrations greater than 2 mM or 6 mM, respectively, were also inhibitory. Activity was strongly inhibited by 4 mM-ADP, 1 mM-PP1 or 20 mM-NaF. The effect of ADP might have resulted from reversing the equilibrium of the kinase reaction. The activation by phosphate ions might indicate a role for the enzyme in regulating intracellular phosphate levels or maintaining a phosphorus reserve. The level of enzymic activity in the bacteria responded to changes in inorganic phosphate concentration in the medium. Basic proteins, such as protamine, could substitute for histone as activator. Proteins such as casein or bovine serum albunim would also substitute for histone but only in the absence of inorganic phosphate. The presence of a protein might be necessary to form a complex with the product, thus preventing reversal of the reaction in vitro. The reaction product was characterized, and found to be labile in hydroxylamine, base, and acid at 100 degrees C. It behaved as a long-chain-polyphosphate molecule on chromatography in an Ebel's solvent. The enzymic activity was therefore not that of a protein kinase.
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PMID:Purification and characterization of a polyphosphate kinase from Arthrobacter atrocyaneus. 16 7

Effects of cyclic adenosine 3':5'-monophosphate (cyclic AMP)-dependent protein kinase were studied in sarcoplasmic reticulum prepared from cardiac and slow and fast (white) skeletal muscle. Cyclic AMP-dependent protein kinase failed to catalyze phosphorylation of fast skeletal muscle microsomes as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Cyclic AMP-dependent protein kinase was without effect on calcium uptake by these microsomes. Treatment of cardiac microsomes obtained from dog, cat, rabbit, and guinea pig with cyclic AMP-dependent protein kinase and ATP resulted in phosphorylation of a 22,000-dalton protein component in the amounts of 0.75, 0.25, 0.30, and 0.14 nmol of phosphorus/mg of microsomal protein, respectively. Calcium uptake by cardiac microsomes was stimulated 1.8- to 2.5-fold when microsomes were treated with cyclic AMP-dependent protein kinase. Protein kinases partially purified from bovine heart and rabbit skeletal muscle were both effective in mediating these effects on phosphorylation and calcium transport in dog cardiac sarcoplasmic reticulum. Slow skeletal muscle sarcoplasmic reticulum also contains a protein with a molecular weight of approximately 22,000 that can be phosphorylated by protein kinase. Phosphorylation of this component ranged from 0.005 to 0.016 nmol of phosphorous/mg of microsomal protein in dog biceps femoris. A statistically significant increase in calcium uptake by these membranes was produced by the protein kinase. Increases in protein kinase-catalyzed phosphorylation of a low molecular weight microsomal component and in calcium transport by sarcoplasmic reticulum of cardiac and slow skeletal muscle may be related to the relaxation-promoting effects of epinephrine seen in these types of muscle. Conversely, the absence of a relaxation-promoting effect of epinephrine in fast skeletal muscle may be associated with the lack of effect of cyclic AMP and protein kinase on calcium transport by the sarcoplasmic reticulum of this type of muscle.
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PMID:Effects of adenosine 3':5'-monophosphate-dependent protein kinase on sarcoplasmic reticulum isolated from cardiac and slow and fast contracting skeletal muscles. 17 60

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

A protein antigenically related to the simian virus (SV 40) A gene product has been purified to near homogeneity from cells infected with the adenovirus-SV 40 hybrid virus Ad2(+)D2 and shown to contain ATPase (ATP phosphohydrolase, EC 3.6.1.3) and protein kinase (ATP:phosphotransferase, EC 2.7.1.37) activity. Both enzymatic activities copurify with the protein through six stages including one gel filtration column, two ion exchange columns, and a heparin affinity column. Analogous fractions from extracts of cells uninfected or infected with adenovirus 2 alone do not contain these enzymatic activities. The D2 hybrid protein resolves into two forms (I and II) during ion exchange chromatography. Form I, the major species (85%) of the D2 hybrid protein, elutes from DEAE-Sephadex in 0.37 M NaCl and is able to catalyze the hydrolysis of ATP to ADP + P(i) at a rate of 3 mumol/hr per mg. The remaining 10-15% of the D2 hybrid protein consists of form II which elutes from DEAE-Sephadex in 0.29 M NaCl and is able to hydrolyze ATP as well as to incorporate phosphorus from ATP into either the D2 hybrid protein itself or other protein acceptors such as phosvitin. Although both forms are able to bind DNA, the ATPase activity of form I cosediments with SV 40 DNA more efficiently than does the protein kinase activity of form II during glycerol gradient centrifugation. The ATPase activity of form I is efficiently inhibited by addition of anti-T gamma globulin to the reaction mixture whereas control gamma globulin has no effect. Similarly, the phosphorylation of the D2 hybrid protein by form II is inhibited by anti-T gamma globulin. By contrast, phosphorylation of phosvitin is specifically inhibited by antibody only when the immune complex is removed from the reaction mixture. Thus, it appears likely that one and possibly two enzymatic activities are carried out by the D2 hybrid protein. These findings are discussed in terms of mechanisms of SV 40 DNA replication and virally induced transformation.
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PMID:Enzymatic activities associated with a purified simian virus 40 T antigen-related protein. 21 12

Phosphorylation of rat and rabbit troponin from normal skeletal muscles and from skeletal muscles of animals under avitaminosis, denervation and hypokinesia was studied. Phosphorylation was carried out by cAMP-dependent protein kinase with [gamma-33P] as substrate. The incorporation of labelled phosphorus into troponin T of the damaged muscles was decreased as compared to normal. After preliminary dephosphorylation of troponin by alkaline phosphatase immobilized on Sepharose 4B, the ability of damaged muscle troponin for subsequent phosphorylation was also decreased as compared to the control. It may be thus assumed that there exist conformational changes of troponin under muscular system pathologies.
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PMID:[Peculiarities of phosphorylation of skeletal muscle troponin under some forms muscle pathologies]. 21 14

The cAMP receptor site in the regulatory subunit of adenosine 3':5'-monophosphate (cAMP)-dependent protein kinase type I was mapped using analogues of cAMP in which the ribose phosphate moiety was systematically modified. Electronical alteration of the cyclophosphate ring at the 3' and 5' positions by sulfur and nitrogen decreased the affinity of these analogues towards the kinase. Substituents at these positions are not tolerated. Testing the separated diastereomers of derivatives in which one of the exocyclic oxygens at the phosphorus has been substituted by sulfur, it was found that one diastereoisomer is preferentially recognized. Based on these results it is proposed that the hydrophylic cyclic phosphate-ribose moiety of cAMP is bound to the kinase via its 3' and 5'-oxygens, the 2'-hydroxy group and the negative charge in a fixed position. Based on our and other published results it is further proposed, that the adenine moiety is bound in a hydrophobic cleft without any hydrogen bond interactions. The chemical interactions between cAMP and the R subunit of protein kinase type I differ from those found for the binding of cAMP to the chemoreceptor of Dictyostelium discoideum [18].
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PMID:A model for the chemical interactions of adenosine 3':5'-monophosphate with the R subunit of protein kinase type I. Refinement of the cyclic phosphate binding moiety of protein kinase type I. 23 34

The capacity of partially purified rat muscle protein kinase coupled to cyanogen-bromide-activated Sepharose 4B to (radio-)phosphorylate proteins in vitro was evaluated using histones from calf thymus and rat liver and certain proteins as substrates. Data are presented which point to a low substrate specificity of this enzyme. It is demonstrated that even within a short time period histones are efficiently phosphorylated without the introduction of contaminating (phospho-)proteins. Therebye phosphoserine residues are formed. The phosphorylation reaction usually performed at 30 degrees C is shown to function quite efficiently also at 4 degrees C. It proceeds even at 30 degrees C for several hours at pH values close to the physiological range without the release of proteins from the solid matrix. The phosphorus transfer can be largely increased with the use of high ATP concentrations. The stability of the substrates is sufficient to suggest a wide applicability of this solid-state protein kinase in the phosphorylation of proteins either for labeling or as a tool to modify proteins post-synthetically under gentle conditions. The solid enzyme seems to be suitable for radioactively labeling proteins of more complex biological structures, such as membrane surfaces.
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PMID:Solid-state protein kinase. A tool for post-synthetically modifying and radioactively labeling proteins in vitro. 120 51

In Saccharomyces cerevisiae, lack of nutrients triggers a pleiotropic response characterized by accumulation of storage carbohydrates, early G1 arrest, and sporulation of a/alpha diploids. This response is thought to be mediated by RAS proteins, adenylate cyclase, and cyclic AMP (cAMP)-dependent protein kinases. This study shows that expression of the S. cerevisiae gene coding for a cytoplasmic catalase T (CTT1) is controlled by this pathway: it is regulated by the availability of nutrients. Lack of a nitrogen, sulfur, or phosphorus source causes a high-level expression of the gene. Studies with strains with mutations in the RAS-cAMP pathway and supplementation of a rca1 mutant with cAMP show that CTT1 expression is under negative control by a cAMP-dependent protein kinase and that nutrient control of CTT1 gene expression is mediated by this pathway. Strains containing a CTT1-Escherichia coli lacZ fusion gene have been used to isolate mutants with mutations in the pathway. Mutants characterized in this investigation fall into five complementation groups. Both cdc25 and ras2 alleles were identified among these mutants.
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PMID:Control of Saccharomyces cerevisiae catalase T gene (CTT1) expression by nutrient supply via the RAS-cyclic AMP pathway. 254 66

Bacteria continuously adapt to changes in their environment. Responses are largely controlled by signal transduction systems that contain two central enzymatic components, a protein kinase that uses adenosine triphosphate to phosphorylate itself at a histidine residue and a response regulator that accepts phosphoryl groups from the kinase. This conserved phosphotransfer chemistry is found in a wide range of bacterial species and operates in diverse systems to provide different regulatory outputs. The histidine kinases are frequently membrane receptor proteins that respond to environmental signals and phosphorylate response regulators that control transcription. Four specific regulatory systems are discussed in detail: chemotaxis in response to attractant and repellent stimuli (Che), regulation of gene expression in response to nitrogen deprivation (Ntr), control of the expression of enzymes and transport systems that assimilate phosphorus (Pho), and regulation of outer membrane porin expression in response to osmolarity and other culture conditions (Omp). Several additional systems are also examined, including systems that control complex developmental processes such as sporulation and fruiting-body formation, systems required for virulent infections of plant or animal host tissues, and systems that regulate transport and metabolism. Finally, an attempt is made to understand how cross-talk between parallel phosphotransfer pathways can provide a global regulatory curcuitry.
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PMID:Protein phosphorylation and regulation of adaptive responses in bacteria. 255 36


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