Cyclic nucleotide phosphodiesterase of rat pancreatic islets. Effects of Ca2+, calmodulin and trifluoperazine
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Cyclic nucleotide phosphodiesterase activity towards cyclic AMP and cyclic GMP was studied in extracts of rat islets of Langerhans. Biphasic Eadie plots [Eadie (1942) J. Biol. Chem. 146, 85-93] were obtained with either substrate suggesting the presence of both ‘high’- and ‘low’-Km components. The apparent Km values were 6.2 +/- 0.5 (n = 8) microM and 103.4 +/- 13.5 (6) microM for cyclic AMP and 3.6 +/- 0.3 (12) microM and 61.4 +/- 7.5 (13) microM for cyclic GMP. With cyclic AMP as substrate, phosphodeisterase activity was increased by calmodulin and Ca2+ and decreased by trifluoperazine, a specific inhibitor of calmodulin. With cyclic GMP as substrate, phosphodiesterase activity was decreased by omission of Ca2+ or addition of trifluoperazine. Addition of exogenous calmodulin had no effect on activity. The data suggest that Ca2+ may influence the islet content of cyclic AMP and cyclic GMP via effects on calmodulin-dependent cyclic nucleotide phosphodiesterase(s).Keywords:
Trifluoperazine
Cyclic nucleotide phosphodiesterase
Cyclic nucleotide phosphodiesterase
PDE10A
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3',5'-Cyclic nucleotide phosphodiesterases (PDEs, 3',5'-cyclic-nucleotide 5'-nucleotidohydrolase), E.C. 3.1.4.17, catalyse the hydrolysis of a 3',5'-cyclic nucleotide (usually cyclic AMP or cyclic GMP). isobutylmethylxanthine is a nonselective inhibitor with an IC50 value in the millimolar range for all isoforms except PDE 8A, 8B and 9A. A 2',3'-cyclic nucleotide 3'-phosphodiesterase (E.C. 3.1.4.37 CNPase) activity is associated with myelin formation in the development of the CNS.
Cyclic nucleotide phosphodiesterase
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Cyclic nucleotide phosphodiesterase activity towards cyclic AMP and cyclic GMP was studied in extracts of rat islets of Langerhans. Biphasic Eadie plots [Eadie (1942) J. Biol. Chem. 146, 85-93] were obtained with either substrate suggesting the presence of both ‘high’- and ‘low’-Km components. The apparent Km values were 6.2 +/- 0.5 (n = 8) microM and 103.4 +/- 13.5 (6) microM for cyclic AMP and 3.6 +/- 0.3 (12) microM and 61.4 +/- 7.5 (13) microM for cyclic GMP. With cyclic AMP as substrate, phosphodeisterase activity was increased by calmodulin and Ca2+ and decreased by trifluoperazine, a specific inhibitor of calmodulin. With cyclic GMP as substrate, phosphodiesterase activity was decreased by omission of Ca2+ or addition of trifluoperazine. Addition of exogenous calmodulin had no effect on activity. The data suggest that Ca2+ may influence the islet content of cyclic AMP and cyclic GMP via effects on calmodulin-dependent cyclic nucleotide phosphodiesterase(s).
Trifluoperazine
Cyclic nucleotide phosphodiesterase
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Abstract Cyclic nucleotide phosphodiesterases catalyze the hydrolysis of 3′,5′ cyclic nucleotides to the corresponding nucleoside 5′ monophosphates. Multiple forms of cyclic nucleotide phosphodiesterase have been identified in both the cardiac muscle and vascular smooth muscle from various species. These isozymes differ in apparent molecular mass, chromatographic properties, substrate specificity, immunologic reactivity, sensitivity to inhibitors, and mode of regulation. The phosphodiesterases play important roles in the regulation of cyclic nucleotide concentrations, which in turn mediate cellular responses to a variety of biological stimuli. The development of phosphodiesterase inhibitors to increase intracellular cyclic nucleotide levels represents an important pharmacological approach to the treatment of various cardiovascular diseases.
Cyclic nucleotide phosphodiesterase
PDE10A
Phosphodiesterase 3
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3',5'-Cyclic nucleotide phosphodiesterases (PDEs, 3',5'-cyclic-nucleotide 5'-nucleotidohydrolase), E.C. 3.1.4.17, catalyse the hydrolysis of a 3',5'-cyclic nucleotide (usually cyclic AMP or cyclic GMP). isobutylmethylxanthine is a nonselective inhibitor with an IC50 value in the millimolar range for all isoforms except PDE 8A, 8B and 9A. A 2',3'-cyclic nucleotide 3'-phosphodiesterase (E.C. 3.1.4.37 CNPase) activity is associated with myelin formation in the development of the CNS.
Cyclic nucleotide phosphodiesterase
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3',5'-Cyclic nucleotide phosphodiesterases (PDEs, 3',5'-cyclic-nucleotide 5'-nucleotidohydrolase), E.C. 3.1.4.17, catalyse the hydrolysis of a 3',5'-cyclic nucleotide (usually cyclic AMP or cyclic GMP). isobutylmethylxanthine is a nonselective inhibitor with an IC50 value in the millimolar range for all isoforms except PDE 8A, 8B and 9A. A 2',3'-cyclic nucleotide 3'-phosphodiesterase (E.C. 3.1.4.37 CNPase) activity is associated with myelin formation in the development of the CNS.
Cyclic nucleotide phosphodiesterase
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Cyclic nucleotide phosphodiesterase
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Cyclic nucleotide phosphodiesterase was investigated in rat parotid gland to elucidate the regulatory mechanisms for the enzyme. Cyclic nucleotide phosphodiesterase activities from DEAE-cellulose column chromatography showed two main peaks. One of them was eluted with 0.15 M KCl and was fairly specific for cGMP. This enzyme was activated by calmodulin with an increase in Vmax and with no effect on Km. The other one was eluted with 0.25 M KCl and showed a higher specificity for cAMP than for cGMP. This enzyme, however, was not activated by Ca2=nd calmodulin. The presence of calmodulin and an inhibitor substance was confirmed by DEAE-cellulose column chromatography. The inhibitor substance was protein in nature and did not inhibit cAMP phosphodiesterase. These results may indicate that cGMP in rat parotid gland, which is supposed to correlate with secretion, is regulated also by phosphodiesterase through calmodulin and an inhibitor substance.
Cyclic nucleotide phosphodiesterase
PDE10A
Phosphodiesterase inhibitor
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Cyclic nucleotide phosphodiesterase
PDE10A
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Cyclic Nucleotide Phosphodiesterases exist in bodies of creature,which perform important biochemical functions,and it can convert Cyclic Nucleotide into 5'-Nucleotide,and what's more,PDE can regulate Cyclic Nucleotide level together with Adenyl cyclase. According to different characteristics,there are many kinds of PDE. Altogether PDE have been divided into two type. One is Calmodiulm-dependent Cyclic Nucleotide Phosphodiesterases,which can be activated ;the other cannot be activated; the other cannot be activated, which doesn't need Calmodiulm. If we want to have a deep research in Cyclic Nucleotide, Calmodulin and mechanisms of killing pests and so on. At first separate and get the two kinds of PDE. Through this experiment, we have not only extracted and purified them, but tested their activity.
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PDE10A
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