2009 - Inhibitory effect of Pb2+ on the transport cycle of the Na+,K+-ATPase

Icon N1   SURFE²R ONE (a predecessor model of SURFE²R N1) publication in Chemical Research in Toxicology (2009)

Gramigni E., Tadini-Buoninsegni F., Bartolommei G., Santini G., Chelazzi G., Moncelli M.R.

Chemical Research in Toxicology (2009) 22(10):1699-1704


The effect of Pb2+ on the transport cycle of the Na+,K+-ATPase was characterized in detail at a molecular level by combining electrical and biochemical measurements. Electrical measurements were performed by adsorbing purified membrane fragments containing Na+,K+-ATPase on a solid-supported membrane. Upon adsorption, the Na+,K+-ATPase was activated by carrying out concentration jumps of different activating substrates, for example, Na+ and ATP. Charge movements following Na+,K+-ATPase activation were measured in the presence of various Pb2+ concentrations to investigate the effect of Pb2+ on different ion translocating steps of the pump cycle. These charge measurements were then compared to biochemical measurements of ATPase activity in the presence of increasing Pb2+ concentration. Our results indicate that Pb2+ inhibits cycling of the enzyme, but it does not affect cytoplasmic Na+ binding and release of Na+ ions at the extracellular side at concentrations below 10 μM. To explain the inhibitory effect of Pb2+ on the Na+,K+-ATPase, we propose that Pb2+ may interfere with the hydrolytic cleavage of the phosphorylated intermediate E2P, which occurs in the K+-related branch of the pump cycle.

Download here

Back to Overview

We use cookies on our website. Some of them are essential for the operation of the site, while others help us to improve this site and the user experience (tracking cookies). You can decide for yourself whether you want to allow cookies or not. Please note that if you reject them, you may not be able to use all the functionalities of the site.