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)

Human chorionic somatomammotropin extracted and purified from placenta at term was proved to have a lipolytic action in the epididymal fat pad of rats. The following mechanism appears to be involved in the lipolytic action of the hormone; human chorionic somatomammotropin activates adenyl cyclase, thereby increasing the concentration of cyclic AMP in the tissue, which, in turn, activates protein kinase to lead to the activation of hormone sensitive lipase.
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PMID:Lipolytic action of human chorionic somatomammotropin. 16 57

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

In red cell preparations from reticulocyte-poor (untreated animals; approximately 2% reticulocytes) and reticulocyte-rich blood (animals pretreated with acetylphenylhydrazide; approximately 60% reticulocytes) of rats, cAMP binding sites and cAMP-dependent protein kinase activities were determined. High affinity binding sites for cAMP were present both in membrane and cytoplasmic preparations; while the apparent binding constants determined in both cell fractions (approximately 3 x 10(-9) M for membrane, approximately 2 x 10(-8) M for cytoplasmic fractions) were independent of the reticulocyte content of the preparations, the respective numbers of sites were about twice as high in the reticulocyte-rich as in the reticulocyte-poor preparations. In membrane preparations, significant cAMP-dependent protein kinase activity could be detected only in membrane fractions from reticulocyte-rich blood which were considerably contaminated by intracellular components ("haemoglobin-containing membranes') while in washed ("haemoglobin-free') membranes no cAMP-dependent protein kinase activity was found. In cytoplasmic preparations both from reticulocyte-poor and reticulocyte-rich blood, two different protein kinases, a low and a high Ka enzyme, were tentatively differentiated by kinetic data; the apparent activation constant for the high Ka enzyme (approximately less than 5 x 10(-8) M) was in the concentration range of the binding constants determined on cytoplasmic preparations. The activity of the high Ka protein kinase was several fold higher in reticulocyte-rich than in reticulocyte-poor cytoplasmic fractions, while the activity of the low Ka enzyme was obviously independent of the reticulocyte content. From the results obtained, it is concluded that in premature rat erythrocytes, membrane protein(s) may serve as protein substrates for cAMP-dependent protein kinase(s) located in the cytoplasm. This assumption was supported by experiments with intact erythrocytes (prelabelled with inorganic 32P-phosphate) from reticulocyte-rich blood: isoprenaline, theophylline, and also dibutyryl-cAMP significantly increased phosphorylation of membrane protein of these cells. From the results presented (and others previously reported) it becomes evident that only premature rat erythrocytes, i.e. reticulocytes, are equipped with a beta-adrenergic receptor-effector system consisting of a beta-adrenergically stimulated adenyl cyclase and cAMP-dependent protein kinase(s). Obviously, the adrenergic receptor system and also part of the effector system is lost during the process of red cell maturation.
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PMID:Cyclic AMP-dependent protein kinases and binding sites for cyclic AMP in rat erythrocytes. 17 4

Cadmium, in addition to producing a variety of toxic manifestations, is known to accumulate in certain "target" organs which include liver and kidney where histological and functional damage becomes apparent. The daily intraperitoneal injection of cadmium chloride for 21 or 45 days stimulated the activities of hepatic pyruvate carboxylase, phosphoenolpyruvate carboxykinase, fructose-1, 6-diphosphatase and glucose-6-phosphatase elevated blood glucose and urea, and lowered hepatic glycogen in rats. Whereas chronic Cd treatment failed to alter adenosine-3', 5'-monophosphate phosphodiesterase (PDE) activity, cyclic AMP (cAMY and the activity of basal and fluoride-stimulated forms of hepatic adenylate cyclase (AC) were markedly increased. However, the cAMP binding to hepatic protein kinase was decreased as was the kinase activity ration. An acute dose of Cd decreased hepatic glycogen content and increased blood glucose, serum urea, and hepatic cAMP. Chronic exposure to Cd induced adrenal hypertrophy and augmented adrenal norepinephrine and epinephrine as well as the activity of adrenal tyrosine hydroxylase. This treatment decreased prostatic and testicular weights of mature rats. Although cAMP as well as AC activity of the prostate gland were reduced, cAMP binding to the prostatic protein kinase was increased as was the activity of the cAMP-dependent form of the enzyme. Testicular AC and PDE activities, however, were stimulated, although cAMP remained unaffected. Whereas the activities of the cAMP-dependent and the independent forms of testicular protein kinase were significantly depressed, the binding of cAMP to protein kinase from testes of Cd-treated rats was not affected. In most cases, the observed metabolic alterations persisted up to 28 days on cessation of Cd administration. Subacute Cd treatment suppressed pancreatic function as evidenced by lowered serum immunoreactive insulin (IRI) in presence of hyperglycemia, as well as by partial inhibition of phentolamine-stimulated increases in serum IRI. Although chronic Cd treatment failed to alter the concentration of brain stem norepinephrine and cerebrocortical acetylcholine esterase activity, serotonin levels of brain stem were depressed and the concentration of striatal dopamine and cerebrocortical acetylcholine were significantly elevated when compared with the values seen in control nonexposed animals.
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PMID:Aspects of the biochemical toxicology of cadmium. 17 84

Testicular and cauda epididymal sperm were obtained via catheters previously implanted in the rete testis and proximal vas deferens of bulls and were used to examine the relationships among sperm motility, cyclic adenosine 3':5'-monophosphate (cAMP) level, adenine nucleotide levels, and rates of glucose and oxygen consumption. Testicular, cauda epididymal, and ejaculated sperm contain cAMP-stimulated protein kinase, adenylate cyclase, and nucleotide phosphodiesterase. Treatment of the nonmotile testicular sperm with phosphodiesterase inhibitors resulted in a doubling of cellular cAMP concentration and a 25% increase in their glucose consumption. No change in motility, ATP level, or rate of oxygen consumption was observed. Sperm in neat cauda epididymal semen had flagellating tails but no progressive motility. Dilution of these sperm into glucose-containing buffer resulted in an increase in intracellular cAMP concentration and a decrease in ATP level with concomitant increases in ADP and AMP levels. These biochemical changes occurred within 30 s after dilution and apparently preceded the initiation of progressive motility by most cells. Since sperm in neat cauda epididymal semen became progressively motile when diluted with neat cauda epididymal plasma as well as accessory sex gland fluid or buffer, composition of the fluid surrounding the sperm is not responsible for the initiation of progressive motility upon dilution nor does cauda epididymal plasma contain an inhibitory factor. Perhaps release from contact immobilization provides the stimulation for the initial acquisition of progressive motility by cauda epididymal sperm. We conclude that during epididymal passage sperm develop from a cell physically unresponsive to changes in cAMP concentration to a form which initiates progressive motility upon changes in cAMP concentration.
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PMID:Adenine nucleotide changes at initiation of bull sperm motility. 17 61

Androgenic deprivation resulted in marked impairment of prostate weight and significant alterations in cytosolic and particulate protein kinase activities and cyclic AMP-binding capacity of this tissue. Whereas rats orchidectomized for 7 days exhibited significant enhancement in the specific activity of cytosolic cyclic AMP-dependent (73%) and -independent (45%) protein kinases as well as cyclic AMP-binding protein (196%), administration of testosterone (5.0 mg/100 g, i.m., 5 days) exerted little or no effect in reversing these responses. In contrast, when expressed as total enzyme activity per prostate, castration led to marked decreases in protein kinase activity assayed in the presence (87%) and absence of the cyclic nucleotide (91%). Likewise, the cyclic AMP-binding capacity of the soluble enzyme was depressed (77%) following androgenic deprivation. Although testosterone treatment for 3 days significantly reversed these effects, complete restoration was not achieved even after 5 days of androgen replacement therapy. Moreover, while exogenous cyclic AMP had no effect on protein kinase activity from crude nuclear preparations, the phosphorylation of endogenous nuclear substrates was dependent on androgenic status of the animals. Whereas castration produced decreases in the specific and total activity of prostatic particulate protein kinase as well as the cyclic AMP-binding protein, testosterone replenishment was effective in abolishing these alterations seen in orchidectomized rats. Data from the present study provide additional support to the concept that changes in cyclic AMP-adenylate cyclase-protein kinase system play an important role in the overall mechanism(s) by which male sex steroids exert their diverse anabolic effects on male accessory sex tissues.
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PMID:Androgenic effects on protein kinases and cyclic AMP-binding protein in the ventral prostate. 17 34

Protein kinase, phosphodiesterase and adenylate cyclase of plasma membrane of adipocytes and the effect of the feedback regulator (FR) on these three enzymes was measured and compared. The basal level ratio of adenylate cyclase to phosphodiesterase to protein kinase was 1:1.9:3.0. Epinephrine and/or FR alters this ratio. FR stimulated protein kinase activity up to 3 fold in the presence of a wide range of enzyme concentrations, 5-50 mug membrane protein/tube. The concentration of FR effective for stimulation of membrane protein kinase was much greater than that needed for inhibition of adenylate cyclase and phosphodiesterases. The inhibition by FR on adenylate cyclase was the most potent effect among the 3 enzymes. 1 U (or 2 U/ml) of FR inhibited 50% of the adenylate cyclase activity in a defined system. The maximum effective concentration of FR for stimulation of membrane protein kinase was greater than 10 U/ml. Histone type 11A was the best substrate for protein phosphorylation so far observed. The FR stimulatory effect was observed at all substrate concentrations used ranging from 1-5 mg/ml. A NaF concentration curve shows that 15 mM NaF gave maximum phosphorylation. The stimulatory effect of FR was observed both in the presence and absence of NaF. Protein kinase of adipocyte plasma membrane was mainly cAMP-independent. The effect of FR (20 U/ml) in stimulation of protein phosphorylation was much greater than that of cAMP (1 X 10(-6) M). The cAMP and FR effects seemed to be additive. Preincubation of plasma membrane with FR in the absence of ATP resulted in no decrease but slight increase in protein kinase activity. A shift in protein kinase, phosphodiesterase and adenylate cyclase ratios by FR suggests the regulatory role of FR in cAMP metabolism in adipocytes.
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PMID:Influence on adipocyte plasma membrane bound protein kinase by feedback regulator. 17 96

In rats rendered tolerant to the dependent on morphine, striatal cyclic AMP metabolism was significantly enhanced as reflected by elevated cyclic AMP levels and adenylate cyclase activity. Following withdrawal from morphine treatment, whereas the activity of straital adenylate cyclase was significantly reduced when compared to morphine-dependent rats, the drop in cyclic AMP was not significant. Although addition of dopamine (40 muM) stimulated equally well the striatal adenylate cyclase from control or morphine-dependent animals, the activity of dopamine-stimulated enzyme was blocked in animals undergoing withdrawal. The crude synaptosomal fraction of the whole brain obtained from morphine-dependent rats exhibited an even more pronounced increase in cyclic AMP which was accompanied by elevated adenylate cyclase and protein kinase activity. Naloxone administration suppressed this rise in cyclic AMP and reversed the morphine-stimulated increases in adenylate cyclase and protein kinase. Following the withdrawal of morphine treatment, alterations in cyclic AMP metabolism were similar to those noted for the morphine-naloxone group.
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PMID:Effect of narcotic dependence and withdrawal on striatal dopamine-sensitive adenylate cyclase and synaptosomal cyclic AMP metabolism. 18 May 79

Cholera toxin, an activator of adenylate cyclase in a wide variety of cells, is a substrate for the phosphotransferase reaction catalyzed by purified cyclic adenosine 5'-monophosphate dependent bovine cardiac muscle protein kinase and the protein associated with human erythrocyte membranes. Phosphorylation occurs when the toxin is dissociated with 5-20 mM dithiothreitol and is restricted to the A1 or "adenylate cyclase activating" subunit of the toxin.
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PMID:Phosphorylation of the active, A1 component of cholera toxin by protein kinase. 18 Oct 50

The effects of various sugars on the simultaneous release of insulin and accumulation of cyclic AMP were studied in collagenase isolated rat pancreatic islets. D-Glucose stimulated the formation of cyclic AMP at 3 and 60 min of incubation, whether measured by a label incorporation technique, or by the protein kinase binding assay of Gilman. Only D-glucose and D-mannose were able to stimulate insulin release and cyclic [3H]AMP accumulation in the absence of other substrate. D-fructose had a stimulatory effect in the presence of 3.3 mM D-glucose only at a high concentration (33.8 mM), and enhanced the effects of 8.3 mM glucose when added at the concentration of 8.3 mM. D-Galactose was effective only together with 8.3 mM D-glucose. The order of potency of these hexoses, both regarding insulin secretion and cyclic [3H]AMP accumulation, was glucose-mannose-fructose-galactose. L-Glucose and 3-O-methylglucose had no effects at 60 min when incubated together with 8.3 mM D-glucose, whereas at 3 min, 3-O-methylglucose induced a small stimulation of the cyclic [3H]AMP response. D-mannoheptulose and D-glucosamine inhibited the insulin and cyclic [3H]AMP responses to 27.7 mM glucose. Mannoheptulose suppressed completely the glucose effect on cyclic nucleotide accumulation within 90 s. Although under all incubation conditions, the threshold stimulatory or inhibitory concentration of a given agent was identical for insulin release and cyclic [3H]AMP accumulation, these two variables showed quantitative differences in incubations of 60 min, the magnitude of the changes in insulin secretion being larger than that for the cyclic nucleotide. It is suggested that modulation of islet cyclic AMP level is an important step in the transmission of the effect of various sugars on insulin release; however, glucose and possibly other sugars may also enhance insulin release by additional mechanisms not involving the adenylate cyclase-cyclic AMP system of the beta-cell.
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PMID:Effect of hexoses and mannoheptulose on cyclic AMP accumulation and insulin secretion in rat pancreatic islets. 18 Oct 79


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