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 bovine cardiac actin-tropomyosin-troponin complex was phosphorylated in the presence of [gamma-32P]ATP, Mg2+, adenosine 3',5'-monophosphate (cyclic AMP), and bovine cardiac cyclic-AMP-dependent protein kinase. Approximately 81% of the [32P]phosphate incorporated was identified as phosphoserine and phosphothreonine. Gel electrophoresis studies showed that 55% of the [32P]phosphate was associated with the inhibitory component of troponin (Tn-I) and 24% with a protein resembling the tropomyosin-binding component of troponin in the actin complex, respectively. The phosphorylation of Tn-I in the actin complex was inhibited 30% when Ca2+ was increased from 0.1 to 50 muM, but phosphorylation of other components was not affected by increasing Ca2+ concentration. Half-maximal calcium activation of the ATPase activity of reconstituted actomyosins made with the [32P]phosphorylated cardiac actin complex and cardiac myosin was shifted to Ca2+ values higher than those of actomyosins made with the nonphosphorylated actin complex.
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PMID:Phosphorylation of a bovine cardiac actin complex. 15 2

The purpose of this study was to determine whether the previously reported differences in adenylate cyclase activity between the sarcolemma of normal and dystrophic chick muscles are also found in the SR, to search for a possible relationship between the adenylate cyclase changes and the pathophysiology of dystrophy, and to investigate whether the findings can be extended to Duchenne human muscular dystrophy by studying the adenylate cyclase and ATPase activities of erythrocyte ghosts from DMD patients and carriers. Microsomes were separated by standard techniques from the pectoralis muscles of normal and dystrophic ckeckens of various ages. The microsomal yields were significantly larger in dystrophic muscles. Adenylate cyclase activities in dystrophic microsomes were higher than those in matched controls and increased with the progression of the disease. The ratio between the two rose from one at 2 weeks of age to nine at about 9--10 weeks. Kinetic analyses showed that the ks for MgATP2- was about 40 microM (at 3 mM Mg2+ and 0.3 mM Ca2+) both in normal and dystrophic microsomes, that calcium caused umcompetitive inhibition of the enzyme (Ki = 0.2 mM), that the effect of calcium was noncooperative (Hill coefficient, nH = 1), that calcium did not affect the cooperativity for MgATP2-, and that magnesium competitively removed the calcium inhibition and caused additional, cooperative stimulation of the enzymatic activity (ka = 1.5 mM; NH =2). The major difference between normal and dystrophic adenylate cyclase was a higher enzymatic velocity in the latter, suggesting a larger amount of enzyme. We investigated whether altered cAMP levels may effect calcium accumulation. Calcium uptake measured (in the presence of oxalate) at several ages revealed no difference between normal and dystrophic chickens. The extent of calcium binding was also similar, although the kd for Ca2+ was lower in dystrophic microsomes. Binding was enhanced in the presence of exogenous protein kinase, but the responses of normal and dystrophic tissues were similar. We concluded that the elevation of adenylate cyclase in dystrophy was not related to microsomal calcium accumultion. Ivestigation of the localization of microsomal adenylate cyclase supported this view. Separation of calcium-loaded microsomes on a discontinuous sucrose gradient into four fractions demonstrated that adenylate cyclase activity, measured in the presence of Lubrol-PX and EGTA, was inversely related to calcium-accumulating activity. Na+, K+-ATPase comigrated with adenylate cyclase. Highest specific activities were found in the lightest fraction. These observations were confirmed by histochemical studies. The reaction product from adenylate cyclase activity was present predominantly in the terminal cisternae of the SR. In the context of the literature, our findings suggest that the rises in adenylate cyclase and Na+, K+-ATPase in avian dystrophy are compensatory changes, elicited by a defect in ECC at the calcium release step...
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PMID:Adenylate cyclase in muscular dystrophy. 15 10

Isoelectric focusing of a purified fraction of thermostable modulator of 3',5'-AMP-dependent protein kinase revealed five individual proteins, the main protein having an isoelectric point of 4,05. The molecular weight of this protein as determined by gel filtration is 8000--9000. The protein with a pI of 4,05 binds Ca2+ and in contrast to the original modulator inhibits the endogenous 3',5'-AMP-dependent phosphorylation of synaptic membranes. An addition of the original modulator fraction to the microsomes isolated from nervous tissue increases the Mg, Ca-ATPase activity and absorption of 45Ca. Neither the protein with a pI of 4,05 nor other individual proteins affect the activity of transport ATPase. The activating effect is partly restored after mixing of all the five subfractions. It is assumed that these proteins are aggregated by Ca2+ and change the activity of ATPase or membrane 3',5'-AMP-dependent protein kinase depending on the concentration of calcium ions.
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PMID:[Effect of thermostable protein kinase modulator on Mg, Ca-ATPase from nervous tissue]. 15 29

At least three mechanical changes characterize the response of cardiac muscle to agents that enhance cyclic AMP production. In common with other inotropic interventions, tension is augmented and the rate of tension rise is increased. The third response, acceleration of the rate of relaxation, is characteristic of the actions of beta-adrenergic agonists. These mechanical effects can be attributed to changes in (1) the amount of Ca2+ released during systole, (2) the rate of Ca2+ release at the onset of systole, and (3) the rate at which Ca2+ is reaccumulated by the sarcoplasmic reticulum at the end of systole. The ability of cyclic AMP-dependent protein kinases to phosphorylate the cardiac sarcoplasmic reticulum in vitro parallels stimulation of both Ca2+ transport and Ca2+-activated ATPase. The phosphoprotein formed in the presence of cyclic AMP and protein kinase has the chemical characteristics of a phosphoester, contains mostly phosphoserine, and has an electrophoretic mobility in SDS polyacrylamide gels that corresponds to a protein of 22,000 daltons. This 22,000-dalton protein, tentatively named phospholamban, thus differs from the acyl phosphooprotein formed by the Ca2+-transport ATPase, which as an apparent molecular weight of 90,000 to 100,000 daltons. Phospholamban has not been found in fast skeletal muscle, nor is Ca2+ transport accelerated by cyclic AMP and protein kinase in sarcoplasmic reticulum from these muslces which do not respond to beta-adrenergic agonists with accelerated relaxation. It thus appears likely that phosphorylation of phospholamban correlates both with an increased rate of Ca2+ transport by cardiac sarcoplasmic reticulum in vitro and accelerated relaxation in the intact myocardium. Preliminary findings are consistent with the view that phosphorylation of phospholamban may be related to other actions on Ca2+ fluxes brought about by agents which activate adenylate cyclase in the myocardium, but these interpretations must remain speculative pending more definitive studies.
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PMID:Control of calcium transport in the myocardium by the cyclic AMP-Protein kinase system. 16 80

A protein phosphokinase (ATP: protein phosphotransferase EC 2.7.1.37) which is stimulated by 3',5'-cyclic adenosine monophosphate (cyclic AMP) has been partially purified from both the cytoplasmic and membrane fractions of human platelets. The kinetics of both enzymes preparations are similar in respect to cyclic AMP, ATP, ADP and AMP. 5-10-minus 7 M cyclic AMP stimulated both preparations by approximately 100%. Both ADP and AMP at a concentration of 5-10-minus 5 M inhibited protein phosphokinase activity of the soluble and membrane preparation by between 50% and 70%. The response of the two enzyme preparations to calcium differed. 10 mM Ca-2+ inhibited soluble protein phosphokinase activity approximately 80% both in the presence and absence of 5-10 minus 7 M cyclic AMP whereas the same concentrations of Ca-2+ inhibited the membrane-bound enzyme by approximately 60% in the presence of 5-10-minus 7 M cyclic AMP and 40% in the absence of cyclic AMP. This observation may be of importance in understanding the mechanism of platelet aggregation.
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PMID:The effect of ADP, calcium and some inhibitors of platelet aggregation on protein phosphokinases from human blood platelets. 16 30

Guanosine 3':5'-monophosphate(cyclic GMP)-dependent protein kinase which catalyzes the phosphorylation of histone was purified about 200-fold from the soluble fraction of pig lung by pH 5.5 precipitation, DEAE-cellulose column chromatography, and Sephadex G-200 gel filtration. The apparent Ka values for guanosine 3':5'-monophosphate and adenosine 3':5'-monophosphate were determined to be about 17 and 360 nM, respectively. Mg2+ was essential for the activity exhibiting biphasic stimulation behavior and neither Mn2+ nor Ca2+ could substitute for Mg2+. However, these divalent ions markedly inhibited the protein kinase activity stimulated by cyclic GMP in the presence of Mg2+.
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PMID:Partial purification and properties of guanosine 3':5'-monophosphate-dependent protein kinase from pig lung. 17 Feb 61

Catecholamine-sensitive adenylate cyclase, cyclic nucleotide phosphodiesterase, adenosine 3', 5'-monophosphate (cyclic AMP)-dependent protein kinase, kinase substrate, and phosphoprotein phosphatase have variously been reported to be present in preparations of myocardial cellular membranes that function in the movement of Ca2+ in and out of the cell and in intracellular Ca2+ translocations, indicating that these membranees possess the equipment for the formation and destruction of cyclic Amp as well as for the initiation, effectuation, and termination of a possible membrane action of the nucleotide. It has also been observed that phosphorylation of seryl residues of protein in sarcolemma- and sarcotubule-rich myocardial subcellular fractions by cyclic AMP activated intrinsic and extrinsic protein kinases confers upon these membran structures an enhanced ability to bind or take up Ca2+ and that dibutyryl cyclic AMP, like adrenaline, produces in intact cardiac muscle simultaneous increases in contractile force and in the uptake of extracellular Ca2+. These findings are suggestive of a second messenger role of cyclic AMP in the beta-adrenoreceptor-mediated actions of catecholamines on myocardial contractile force and relaxation, in which Ca2+ would serve as a third messenger and be subject, respectively, to more effective removal from its binding sites on troponin. An alternative interpretation regards Ca2+ and cyclic AMP as interdependent twin second messengers in the catecholamine-induced inotropism. Since the physiological meaning of the reported effects of cyclic AMP on isolated myocardial membrane preparations is far from established an instances of a dissociation between the effects of catecholamines on myocardial contractile force and cyclic AMP levels have been observed, there is still room for hypotheses that relegate cyclic AMP to a nonobligatory, at most, supportive role in the action of the catecholamines on cardiac contraction.
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PMID:Adenosine 3',5'-monophosphate, the myocardial cell membrane, and calcium. 17 10

An increase in activity of disulphide reductase system (DRS) in supernatant of liver tissue was caused by 3',5'-AMP, ATP, GTP, UTP, Mg2+, Ca2+, EDTA, protamine, noradrenaline and F-. The effect was connected with arsenite resistant fraction of DRS. After rapid homogenization the effect of noradrenaline disappeared and the effects of ATP, GTP, UTP and Ca2+ were distinctly decreased. Treatment with adsorbents prevented the effects of 3',5,-AMP, ATP and EDTA and markedly decreased the effects of protamine and Mg2+. A protein inhibitor of protein kinase prevented completely the activation of DRS with 3',5'-AMP, ATP, GTP, UTP and noradrenaline and distinctly decreased the effect of protamine, Mg2+ and Ca2+ but did not alter the influence of EDTA. Addition of 2',3'-AMP blocked the effect of 3',5-AMP, ATP and Mg2+ but did not influence the effect of protamine and EDTA. The data obtained suggest that protein kinase participated in activation of DRS by most of the regulators.
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PMID:[Study of mechanisms of regulation of disulphide reductase in mouse liver]. 17 2

Increases in protein kinase-catalyzed phosphorylation of a 22000 dalton protein correlated closely with increases in phosphate-facilitated calcium transport measured concurrently in canine cardiac sarcoplasmic reticulum under similar conditions in the presence of varying concentrations of bovine cardiac protein kinase. A correlation coefficient of 0.93 and a P value of less than 0.001 were obtained. Protein kinase-catalyzed phosphorylation of the 22000 dalton microsomal protein may mediate the abbreviation of systole seen in the mammalian heart in response to inotropic agents like catecholamines.
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PMID:Correlation between protein kinase-mediated stimulation of calcium transport by cardiac sarcoplasmic reticulum and phosphorylation of a 22000 dalton protein. 17 31

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


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