EFFECTS OF WEAK LOW-FREQUENCY SINUSOIDAL AND DC MAGNETIC-FIELDS ON MYOSIN PHOSPHORYLATION IN A CELL-FREE PREPARATION

The effects of weak, environmental range, sinusoidal (ac), and dc magnetic fields on myosin light chain phosphorylation in a cell-free system were studied. This enzyme system is Ca2+-calmodulin dependent, providing a well established ion binding mechanism for this investigation. The exposure system applied dc (0-200 muT, vertically and/or horizontally controlled) and/or ac (16 Hz, 20.9 muT) magnetic fields. The results appear to suggest that all of the ac and dc, as well as combinations of ac/dc magnetic fields, significantly (30-100%, p < 0.01) influenced myosin phosphorylation. The most surprising and important finding was that variations of the dc magnetic field (in the absence of ac components) were not only sufficient to alter the rate of phosphorylation, but also gave the maximum effect. Experiments with Mumetal shielding, which decreased the ambient dc and ac magnetic fields to +/-0.1 muT, also resulted in a decrease of phosphorylation, to 35% of the control value. Study of phosphorylation kinetics showed a typical ''S'' shaped enzyme-substrate dependence, which again was modified by the dc field.