Inhibitory effect of melittin on Na+,K+-ATPase from guinea pig myocardial mitochondria.
OBJECTIVE
To investigate the effect of melittin (Mel) of Na+,K+-ATPase activity and it's kinetic mode of action on guinea pig myocardial mitochondria.


METHODS
Effect of Mel on heart mitochondrial Na+,K+-ATPase activity was determined with colorimetry method.


RESULTS
Mel inhibited Na+,K+-ATPase in a concentration and time dependent manner, IC50 was 2.60 micromol/L. Kinetic studies of interaction between Mel and K+, Na+, ATP revealed that inhibitory effect of Mel was competitive with K+, but not with Na+ and ATP.


CONCLUSIONS
Mel polypeptide potently inhibits Na+,K+-ATPase, possibly by binding to the K+ site.
Yang
S
S
Department of Pharmacology, School of Pharmacy, Fudan University, Shanghai 200032, China. mhjiang@shmu.edu.cn
Zhang
X M
XM
Jiang
M H
MH
D000818:Animals; D001667:Binding, Competitive; D005260:Female; D006168:Guinea Pigs; D020128:Inhibitory Concentration 50; D008297:Male; D008555:Melitten / Q000494:pharmacology*; D008929:Mitochondria, Heart / Q000201:enzymology*; D011188:Potassium / Q000494:pharmacology; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*
D008555:Melitten; D000254:Sodium-Potassium-Exchanging ATPase; D011188:Potassium