Electron flow at the polarized mercury-water interface in the presence of membrane fragments rich in Na(+)-K (+)-Activated ATPase.

Measurements of interfacial electron flow indicate that membrane fragments rich in Na(+)-K(+)-ATPase are capable of absorbing and releasing electrons in the form of random currents at an electrode surface. The electron transporting system, which functions in the presence or absence of substrate and activating ions, may be part of or in contact with the enzyme system, but it is not related to the ATPase activity. The observed electron transport at an electrode surface resembles physiological electron transport processes in being reversible, in extending over the same range of potential, and in being affected by some of the chemicals that interfere with electron transport and oxidative phosphorylation in mitochondria. Our experiments do not provide sufficient evidence to identify the substances that are responsible for the random currents, but the results suggest that the electro-active substances are similar to those which are involved in the reactions at the second phosphorylation site in mitochondria. Experiments with this technique provide a new approach to the study of the mechanism of biological electron transport processes and their possible relation to ATP synthesis and hydrolysis.