Document Detail

Calcium-dependent 3':5'-cyclic nucleotide phosphodiesterase. Inhibition of basal activity at physiological levels of potassium ions.
MedLine Citation:
PMID:  214428     Owner:  NLM     Status:  MEDLINE    
A calcium-dependent cyclic nucleotide phosphodiesterase from rat cerebrum was, in the absence of activator protein, inhibited by various monovalent cations. The inhibition was rapid, readily reversible, and concentration-dependent, with 100 mM cesium, rubidium, or potassium ion inhibiting essentially all basal enzyme activity, while 100 mM sodium or lithium ions produced only moderate inhibition. The potency of the cations in inhibiting the enzyme was Cs greater than or equal to Rb greater than K greater than Na greater than or equal to Li. Potassium ions increased the apparent Km for cyclic GMP and cyclic AMP by 3- and 5-fold, respectively. At 100 mM, the monovalent cations inhibited enzyme activated by the calcium-dependent activator by only 15 to 30%, while at 55 mM no inhibition pertained. Potassium and sodium ions at 55 mM had no effect on the calcium-independent phosphodiesterase from rat cerebrum. The results indicate that at normal intracellular concentrations of potassium ions the activity of the calcium-dependent phosphodiesterase is virtually completely dependent on the presence of calcium plus activator protein.
C W Davis; J W Daly
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  The Journal of biological chemistry     Volume:  253     ISSN:  0021-9258     ISO Abbreviation:  J. Biol. Chem.     Publication Date:  1978 Dec 
Date Detail:
Created Date:  1979-02-12     Completed Date:  1979-02-12     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  2985121R     Medline TA:  J Biol Chem     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  8683-6     Citation Subset:  IM    
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MeSH Terms
3',5'-Cyclic-AMP Phosphodiesterases / isolation & purification,  metabolism*
3',5'-Cyclic-GMP Phosphodiesterases / isolation & purification,  metabolism*
Calcium / pharmacology*
Cations, Monovalent
Cerebral Cortex / enzymology
Enzyme Activation
Potassium / pharmacology*
Reg. No./Substance:
0/Cations, Monovalent; 7440-09-7/Potassium; 7440-70-2/Calcium; EC',5'-Cyclic-AMP Phosphodiesterases; EC',5'-Cyclic-GMP Phosphodiesterases

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