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)

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

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

A method for the preparation of a homogenous catalytic subunit of adenosine 3':5'-monophosphate-dependent protein kinase from pigeon breast muscle was developed. The molecular weight of the enzyme as determined by electrophoresis in the presence of sodium dodecyl sulfate was found to be 42000. The pH optimum of the catalytic subunit was around 8.0. The active site of the catalytic subunit was studied using some derivatives of ATP, containing different reactive groups in the triphosphate chain of the molecule. It may be assumed that the pH optimum of the enzyme inactivation by adenosine 5'-chloromethylpyrophosphonate and the protective effect of ATP suggest covalent binding of the imidazole ring in the enzyme active site. The kinetic mechanism of the protein kinase reaction was studied using the initial rate experiments and reaction product inhibition. The results obtained were consistent with a random Bi-Bi kinetic mechanism.
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PMID:[Some properties of the catalytic subunit of adenosine 3':5'-monophosphate-dependent protein kinase from pigeon breast muscle]. 3 26

Exposure of neuroblastoma cells (NBD-2) to 8-bromo-adenosine 3',5'-cyclic monophosphate (0.2-1.0 mM) (8-Br-cAMP) for 15 min caused a long term increase in the Vmax of tyrosine-3-monooxygenase activity (TH) beginning about 1 day after 8-Br-cAMP application. Cyclic AMP-dependent histone kinase was maximally activated in about 30 min and stayed activated above pretreatment levels for one hour. In cells exposed to 8-Br-cAMP for 15 min, separation of soluble and particle bound histone kinase showed that the total histone kinase activity in the soluble fraction decreased by 40%. This decrease was accompanied by an increase in protein kinase activity in the particulate fraction, suggesting enzyme translocation. After translocation, the enzyme appears to acquire a different substrate affinity because it prefers as a PO43- acceptor, acidic protein rather than histone. In NBD-2 cells this kinase appears to precede, and may be related to, the delayed increase in TH Vmax.
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PMID:Translocation of cytosol protein kinase into nuclei and the induction of tyrosine hydroxylase in NBD-2 neuroblastoma cells. 3 81

Bilateral occlusion of common carotid arteries in Mongolian gerbils was produced for the periods (up to 15 min) which were shown to be totally reversible. There was an initial increase of cyclic AMP and GABA levels and enhanced activities of adenylate cyclase and glutamate decarboxylase, as well as the reduction of norepinephrine level and decreased activities of monoamine oxidase, GABA-transaminase and Na+-K+-ATPase. Following these changes, decreased concentration of dopamine, serotinin and glutamate were found. The activities of total protein kinase and acetylcholinesterase were found to be reduced after longer periods of short-term ischemia. The data are consistent with the concept of increased non-controled release of putative neurotransmitters in ischemia.
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PMID:Alterations of putative neurotransmitters and enzymes during ischemia in gerbil cerebral cortex. 3 75

cAMP independent glycogen synthase kinase and phosvitin kinase activity was purified from the 180 000 x g supernatant of human polymorphonuclear leukocytes by ammonium sulphate precipitation and phosphocellulose chromatography. The cAMP independent glycogen synthase kinase eluted from the phosphocellulose at 0.54 M NaCl (peak A) separate from the major phosvitin kinase eluting at 0.68 M NaCl (peak B). The kinase activity of both peaks tended to form aggregates, but in the presence of 0.6 M NaCl, the peak B enzyme had Mr 250 000, 7.2S and the peak A enzyme Mr 38 000, 3.8S. The ratio between synthase kinase and phosvitin kinase activity in peak A was 1:3.2 and in peak B 1:31.4. In addition the kinase activities differed with respect to sensitivity to temperature, ionic strength and CaCl2. It is suggested that the peak A enzyme represents the cAMP independent glycogen synthase kinase of leukocytes, whereas the peak B enzyme is a phosvitin kinase, which is insignificantly contaminated with some synthase kinase (peak A) and contains a separate, second synthase kinase. Synthase kinase had Kmapp 4.2 microM for muscle glycogen synthease I and Kmapp 45 microM for ATP. GTP was a poor substrate. The activity was not influenced by cyclic nucleotides, Ca2+, or glucose-6-P. Synthase I from muscle and leukocytes was phosphorylated to a ratio of independence of less than 0.05.
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PMID:Purification and properties of cAMP independent glycogen synthase kinase and phosvitin kinase from human leukocytes. 4 Jan 8

1. The ouabain-insensitive Na efflux in barnacle muscle fibres is promptly stimulated by injection of cyclic GMP. The minimal effective injected concentration is found to be about 10(-7) M. This effect of cyclic GMP could not be mimicked by injecting 5'-GMP. 2. External application of ouabain (10(-4) M) to fibres not pretreated with ouabain during the stimulatory response to cyclic GMP causes some inhibition of the Na efflux indicating that cyclic GMP does not cause appreciable inhibition of the Na:K pump. 3. The magnitude of the stimulatory response to injected cyclic GMP depends on the external Ca2+ concentration, as well as pHe but not on the Na+, K+ or Mg2+ concentration. It also depends on pHi, since acidification of HCO3-containing ASW leads to a greater enhancement of the response to cyclic GMP than is observed with acidified HERPES-ASW. 4. Stabilization of myoplasmic pCa by injecting 100 mM-EGTA before or after cyclic GMP fails to alter the magnitude of the response to the nucleotide. Enrichment of the fibre with Mg2+ at the time of injection of cyclic GMP leads to a reduced response. No change in response, however, is seen when the internal free Mg concentration is suddenly reduced by injecting 0.05 M-pyrophosphate with cyclic GMP. 5. Injection of cyclic GMP-dependent protein kinase stimulatory modulator before cyclic GMP fails to enhance the response to the nucleotide. The same is true of the phosphodiesterase inhibitor protein. However pre-injection of 10(-2) M-papaverine enhances the response to a subsequent injection of 10(-3) M-cyclic GMP. 6. Injection of pure protein kinase inhibitor (1.6 x 10(-4) M) before 10(-3) M-cyclic GMP reduces the response to the nucleotide. 7. The argument is put forward that injected cyclic GMP stimulates the ouabain-insensitive Na efflux mainly by activating cyclic AMP-protein kinase rather than cyclic GMP-proton kinase.
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PMID:Stimulation by cyclic GMP of sodium efflux in barnacle muscle fibres. 4 Oct 90

Most of the cyclic AMP-dependent protein kinase activity in propylthiouracil-induced goiters and control rat thyroid glands was found in the soluble fraction. The activity in the particulate fractions was cyclic AMP-independent. Protein kinase activity was 2--3-fold higher in all the subcellular fractions of goitrous tissue than of control tissue. In the presence of Triton X-100, both groups showed a significant increase in kinase activity in all subcellular fractions, and the kinase activity in the particulate fractions could now be slightly stimulated by cyclic AMP. Again, enzyme activity in fractions from goiters was significantly higher than in control tissue. Two major peaks, Types I and II, of soluble cyclic AMP-dependent protein kinase activity could be separated by DEAE-cellulose chromatography. Chronic in vivo stimulation by TSH was associated with a selective increase in Type II isoenzyme activity. Elution and pH profiles, dissociation of subunits with 0.5 M NaCl, and activity ratios (-cyclic AMP/+cyclic AMP) for various substrates for Type II isoenzyme in goitrous and control tissue were similar. The elevated activity in goitrous tissue was manifested by an increase in V for histone, ATP, Mg2+ and cyclic AMP, with no change in the apparent Km.
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PMID:Properties of cyclic AMP-dependent protein kinase in normal and goitrous rat thyroid gland. 4 80

Kinase activity detected in immune complexes containing the src gene product of the avian sarcoma virus has been reported. To further characterize this immune complex kinase, we developed a routine quantitative assay involving trichloroacetic acid precipitation on filters. The enzyme reaction required either Mg2+ or Mn2+, but was inactive with Ca2+. The kinetics of the phosphorylation reaction indicated a transient enzyme activity limited by rapid substrate-dependent inactivation of the enzyme. A variety of nucleoside and deoxyribonucleoside triphosphates (dATP, ATP, GTP, CTP, dGTP, TTP, dCTP) served as phosphoryl donors. The phosphorylation of immunoglobulin G was inhibited by the presence of nucleoside diphosphates. Deoxyribonucleoside diphosphates can either stimulate or inhibit the kinase reaction depending upon the concentration used. The unusual enzymatic properties of the immune complex kinase raise the possibility that the enzyme does not function as a protein kinase in vivo, but rather belongs to a different class of kinases (nucleotide kinases) which adventitiously phosphorylates immunoglobulin G when immunoprecipitated with immune serum.
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PMID:Characterization of an immune complex kinase in immunoprecipitates of avian sarcoma virus-transformed fibroblasts. 4 53

1. A study has been made in single barnacle muscle fibres of the effect of micro-injected pure protein kinase inhibitor (PKI) on the response of the Na efflux to injection of cyclic AMP and external acidification. 2. (i) Injection into fibres of 1.6 x 10(-4) M-pure PKI is without effect on the resting Na efflux. (ii) Injection of 1.6 x 10(4) M-pure PKI before 0.03 M-cyclic AMP causes a marked reduction in the magnitude of the response of the Na efflux to the nucleotide. The same is true when 10(-4) M-cyclic AMP is injected after PKI. (iii) Injection of partially pure catalytic subunits causes a sustained stimulation of the ouabain-insensitive Na efflux, which is almost completely reversed by injecting PKI. (iv) Injection of 100 mM-EGTA before PKI fails to alter the lowered response of the ouabain-insensitive Na efflux to injection of 10(-4) M-cyclic AMP. (v) Ouabain (10(-4) M) when applied following the injection of 10(-4) M-cyclic AMP causes a drastic fall in the stimulated Na efflux. 3. (i) Injection of 1.6 x 10(-4) M-pure PKI before or after external acidification fails to abolish or reduce the stimulatory response to acidification. (ii) Injection of 1.6 x 10(-4) M-pure PKI before acidification practically abolishes the response of the ouabain-insensitive Na efflux to 0.03 M-cyclic AMP in the presence of acidification. (iii) Radioimmunoassay of total cyclic AMP and cyclic GMP content in single fibres before and after acidification shows no appreciable alteration in nucleotide content following acidificiation. (iv) Injection of 100 mM-EGTA before acidification enhances the stimulatory response to acidification. (v) External application of Dantrolene (10(-5) M) fails to alter the size of the stimulatory response to acidification. 4. (i) Prior external application of 5 x 10(-4) M-benzolamide results in a marked reduction in the magnitude of the response of the ouabain-insensitive Na efflux to the injection of 3 x 10(-4) M-cyclic AMP. (ii) Benzolamide totally abolishes the response of the ouabain-insensitive Na efflux to the injection of catalytic subunits. 5. The evidence brought forward is compatible with the view that (a) The mechanism by which cyclic AMP stimulates the Na efflux involves activation by cyclic AMP of the cyclic AMP-dependent protein kinase system, and hence release of the catalytic subunit, and (b) the mechanism by which external acidification leads to stimulation of the Na efflux involves activation of a benzolamide-sensitive system, possibly carbonic anhydrase, rather than the adenyl cyclase system. The actions of cyclic AMP and catalytic subunits on the Na efflux are closely linked to activation of the benzolamide sensitive system.
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PMID:Mode of stimulation by injection of cyclic AMP and external acidification of the sodium efflux in barnacle muscle fibres. 4 91


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