Abstract

The Na+,K+-ATPase, a ubiquitous P-type ion pump, is critical for maintaining cellular osmotic balance and generating the electrochemical gradients necessary for numerous physiological processes, including nerve impulse propagation and nutrient transport. This study investigates the electrogenic properties of the purified Na+,K+-ATPase reconstituted into a simplified model system: planar bilayer lipid membranes (BLMs). The primary objective was to characterize the kinetics and thermodynamics of the pump's ion transport cycle in a controlled environment, focusing specifically on the electrical signatures generated during active pumping. We employed the impedance method, a highly sensitive electrical technique, to measure changes in the BLM's capacitance and conductance induced by the pump's activity. The results reveal distinct frequency-dependent electrical responses that correlate with specific conformational changes in the enzyme, providing quantitative data on the partial reactions of the transport cycle. These findings offer novel insights into the molecular mechanism of electrogenic ion translocation by the Na+,K+-ATPase, contributing to a deeper understanding of cellular bioenergetics and the fundamental principles governing active transport across biological membranes.