Inhibition of (Na+, K+)adenosine triphosphatase and its partial reactions by quercetin

The bioflavonoid, quercetin, inhibited the (Na+, K+)adenosine triphosphatase purified from the electric organ of electric eel (Electrophorus electricus) or from lamb kidney. An analysis of its mode of action revealed that the formation of phosphoenzyme from Pi but not from ATP was inhibited. Quercet...

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Bibliographic Details
Published in:Biochemistry (Easton) 1976-11, Vol.15 (23), p.4951-4956
Main Authors: Kuriki, Y, Racker, E
Format: Article
Language:English
Subjects:
Adenosine Triphosphatases - metabolism
Animals
Binding Sites
Electric Organ - enzymology
Electrophorus
Enzyme Activation
Flavonoids - pharmacology
Kinetics
Potassium - pharmacology
Protein Binding
Quercetin - pharmacology
Sodium - pharmacology
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Summary:The bioflavonoid, quercetin, inhibited the (Na+, K+)adenosine triphosphatase purified from the electric organ of electric eel (Electrophorus electricus) or from lamb kidney. An analysis of its mode of action revealed that the formation of phosphoenzyme from Pi but not from ATP was inhibited. Quercetin increased the amount of ADP-sensitive phosphoenzyme (E1--P), indicating an inhibition of the conversion of E1--P to the ADP-insensitive form (E2--P). The rate of dephosphorylation of the phosphoenzyme formed from ATP was slowed by quercetin. These results suggest that quercetin inhibits the formation of E2--P from either Pi or E1-P as well as the hydrolysis of the phosphoenzyme. Its mode of action is therefore different from that of ouabain and other inhibitors of the Na+, K+)adenosine triphosphatase.
ISSN:0006-2960
DOI:10.1021/bi00668a001