Inhibitory effect of melittin on Na+, K+-ATPase from guinea pig myocardialmitochondrial

AIM: To investigate the effect of melittin (Mel) of Na+,K+-ATPase activity and it's kinetic mode of action on guinea pig myocardial mitochondria. METH ODS: Effect of Mel on heart mitochondrial Na+,K+-ATPase activity was determ ined with colorimetry method. RESULTS: Mel inhibited Na+,K+-ATPase in a con centration and time dependent manner, IC50 was 2.60 mu mol/L. Kinetic studi es of interaction between Mel and K+, Na+, ATP revealed that inhibitory eff ect of Mel was competitive with K+, but not with Na+ and ATP. CONCLUSION: M el polypeptide potently inhibits Na+,K+-ATPase, possibly by binding to the K+ site.