Frequency dependence of Na,K-ATPase function in magnetic fields

The mobile charge interaction (MCI) model of signal transduction in electromagnetic fields was developed to explain how electric and magnetic field effects on Na,K-ATPase are closely linked to the activation, a property of the enzyme that determines its ability to function in the absence of an external field. The MCI model predicts that the frequency dependence of Na,K-ATPase function in magnetic fields should be comparable with the previously determined dependence in electric fields, and we have determined the magnetic field dependence in the range 1-3000 Hz. In the range 3-3000 Hz, the frequency dependence of the small (similar to 5-10%) effect appears to be similar to the dependence in electric fields. This is also true of 1 Hz fields (and in some experiments with DC fields), where there is no effect of magnetic field on enzyme function. The frequency dependence appears to be smaller than the dependence on the level of Na,K-ATPase activation, especially at low levels of activation. These results are consistent with the MCI model, where an interaction with either an electric or a magnetic field alone depends upon the same charge transfer processes within the enzyme. (C) 1997 Elsevier Science S.A.