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)

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

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

Adenylate, guanylate cyclase and protein kinases in a fibrous sarcoma originating from rat prostate have been studied. A decrease in levels of adenosine 3', 5'-monophosphate (cyclic AMP) and adenylate cyclase activities and an increase in levels of guanosine 3',5'-monophosphate (cyclic GMP) and guanylate cyclase activities were observed in the tumor tissue when compared with the normal prostatic tissue of rats. Protein kinases from the tumor and the prostate were both responsive to exogenous cyclic AMP, with an apparent Ka of 0.08 muM in the tumor and of 0.11 muM in the prostate. It is of interest that the protein kinases from the tumor responded to cyclic AMP to the same extent as was observed in the enzyme preparation from the prostate. The protein kinase from the tumor was more sensitive to cyclic GMP than that from the prostate, showing an apparent Ka of 0.88 muM in the tumor and of 4.85 muM in the prostate. This tumor has been characterized with an increase in guanylate cyclase activities with a subsequent rise in cellular cyclic GMP and an increased sensitivity of the protein kinase to cyclic GMP.
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PMID:Studies on cyclic nucleotides in cancer. I. Adenylate guanylate cyclase and protein kinases in the prostatic sarcoma tissue. 0 48

A dependence of rat liver urocaninase activity on the agents affecting the adenylate cyclase system was studied in vitro and in vivo. Urocaninase is considerably activated after the injection of glucagone, NaF, theophylline and 3',5'-AMP. Under conditions optimal for the protein kinase activity of phosphorylase the urocaninase of liver extracts was activated 7-fold on the average. The nezyme retains its activity after gel-filtration through Sephadex G-25 and is capable of inactivation in the presence of Mg2+ and of reactivation after addition of ATP and 3',5'-AMP. These data suggest a possibility of regulation of mammalian liver urocaninase activity by 3',5'-AMP-dependent phosphorylation of the enzyme. Derivatives of hypoxanthine (theophylline and caffeine) in concentration 10(-4) M activate urocaninase in liver extracts 2--3 and 1.5-fold respectively. The activation is probably not due to the 3',5'-AMP phosphodiesterase inhibition, since another phosphodiesterase inhibitor--papaverine--has no activating effect on urocaninase.
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PMID:[Regulation of urocaninase activity in the liver: role of 3',5'-AMP]. 1 41

The effect of parathyroid hormone and calcitonin on the renal excretion of phosphate, calcium, and cyclic AMP was evaluated in the thyroparathyroidectomized hamster, a mammal apparently reisstant to the phosphaturic effect of parathyroid hormone. Parathyroid hormone did not increase phosphate excretion, although it decreased excretion of calcium and increased urinary excretion of cyclic AMP. This lack of a phosphaturic response to parathyroid hormone was not reversed by administration of 25-OH vitamin D or infusions of calcium or phosphate. Calcitonin, another potentially phosphaturic hormone, also vailed to increase phosphate excretion but markedly elevated urinary excretion of cyclic AMP. In hamsters pretreated with infusion of urinary ammonium chloride, which decreased plasma and urinary pH, both parathyroid hormone and calcitonin increased excretion of phosphate as well as that of cyclic AMP. Acetazolamide had no phosphaturic effect in ammonium chloride-loaded hamsters, and it decreased cyclic AMP and calcium excretion. Alkalinization of urine by acetazolamide did not prevent the phosphaturic effect of parathyroid hormone in ammonium chloride-loaded hamsters, but it blocked the increase in urinary cyclic AMP excretion. Parathyroid hormone and calcitonin both stimulated adenylate cyclase in a cell-free system (600-g pellet) from hamster renal cortex, elevated tissue cyclic AMP levels, and activated protein kinase in tissue slices from hamster renal cortex. In acid medium, the increase in cyclic AMP and activation of protein kinase in response to parathyroid hormone was diminished, but addition of acetazolamide restored responsiveness of both parameters to control values. Acetazolamide, on the other hand, did not influence adenylate cyclase or its response to parathyroid hormone or cyclic AMP phosphodiesterase activity. We conclude that the lack of a phosphaturic effect of parathyroid hormone and calcitonin in the hamster depends on steps in the cellular action of these hormones, steps that are sensitive to pH subsequent to cyclic AMP generation and protein kinase activation. In addition, acetazolamide may potentiate the phosphaturic effect of parathyroid hormone by promoting accumulation of cyclic AMP in tissue. Thus, the hamster is a particularly useful model for studies of syndromes in which there is renal resistance to phosphaturic hormones.
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PMID:Mechanism of resistance to the phosphaturic effect of the parathyroid hormone in the hamster. 1 74

The effect of an inhibitor of adenylate cyclase (ACI) was measured on some enzymes associated with cyclic nucleotide-regulated metabolism. Soluble guanylate cyclase was inhibited; both soluble and particulate cyclic GMP-phosphodiesterases were stimulated. Cyclic AMP phosphodiesterases were unaffected. In contrast, the activities of Na, K-ATPase, protein kinase, phosphorylase kinase, glycogen synthetase and a number of glycosidases were not altered by equipotent amounts of the inhibitor. It is concluded that this substance acts as a modulator of both cyclic AMP and cyclic GMP metabolism in heart and other tissues.
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PMID:The effect of adenylate cyclase inhibitor (ACI) on guanylate cyclase, phosphodiesterase and other enzymes in heart. 1 79

1. A factor which modulates the activity of cyclic AMP-dependent protein kinase copurifies from rat adipocytes with an inhibitor of adenylate cyclase. Purification and stability studies suggest that both effects reside in a single factor previously referred to as a feedback regulator. 2. The magnitude and direction of the feedback regulator effect on cyclic AMP-dependent protein kinase activity was dependent on the concentration of feedback regulator and the concentration and type of protein substrate. Using histone type IIA as substrate, feedback regulator was inhibitory at low histone concentrations and stimulatory at high concentrations. Preincubation of protein kinase with feedback regulator resulted in inhibition at all histone concentrations. With some protein substrates, e.g. histone f2b and casein, inhibition was observed at all histone concentrations. 3. The stimulation of histone type IIA phosphorylation resulted from an increased V with no effect on either the apparent Ka for cyclic AMP or the Km for ATP. Time course studies suggest that feedback regulator increased the rate of phosphorylation without increasing the total number of phosphorylation sites. Increased histone phosphorylation was observed regardless of whether the cyclic AMP-dependent protein kinase was peak I or peak II (off Deae-cellulose), isolated from bovine or rabbit skeletal muscle or rat heart. A small stimulation was observed using cyclic GMP-dependent protein kinase. 4. These results indicate that feedback regulator can inhibit or stimulate protein kinase, an effect which is probably substrate directed, and depends on the reaction conditions. Whether feedback regulator modulated protein phosphorylation in vivo in addition to its inhibition of adenylate cyclase is unknown. However, stimulation of protein kinase activity in the presence of cyclic AMP is a valuable and rapid assay for monitoring feedback regulator fractions during purification procedures.
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PMID:Modulation of protein phosphorylation by a factor purified from adipocytes. 1 26

Our studies of the hormonal receptor system and of the sequence of enzymatic events interconnecting the initial hormonal stimulus to the brown adipocyte with its final subcellular effect are summarized here. The hormone-mediated regulatory pathway consists of the adenyl cyclase and the protein kinase systems; the former is composed of the receptor and catalytic sites, the latter of regulatory and catalytic subunits. Emphasis is given currently to the diversity and characteristics of the individual components of the protein kinase system, since it seems to carry out the ultimate unifying mechanism involved in a variety of hormone-mediated functions, i.e. the phosphorylation of a protein molecule.
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PMID:The "second messenger" system in brown adipose tissue of developing rats. Its molecular composition and mechanism of function. 2 84

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


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