Studies on the effects of an electromagnetic field on the activity of recombinant luciferase in the luciferase–luciferin–ATP-Mg2+ system were conducted. The enzymatic activity was evaluated by the measurements of biochemiluminescence intensity with a standard chemiluminometer. Frequencies that effectively caused irreversible changes in the enzyme activity were identified. The intensity of chemiluminescence (Icl), after it reached the stationary level, and the time constant of the intensity decay, after cessation of the stationary luminescence due to ATP depletion, were the criteria of the luciferase activity. I0 sharply increased from (250 ± 47) imp/s to (1250 ± 75) imp/s compared to the control under exposure to an electromagnetic field of 6 Hz. At the same time, the duration of the stationary luminescence decreased by approximately five times (from 30 to 5.5 min). The decay of luminescence, τ, accelerated significantly (by nine times relative to the control). An opposite effect of other experimentally chosen frequencies of the electromagnetic field was obtained. As an example, upon exposure to the electromagnetic field with frequencies of 12, 48, and 96 Hz, the luciferase activity decreased by 2 times (at 48 and 96 Hz) and by 4 times (at 12 Hz) compared to the control. Luciferase activity did not differ from the control after exposure to a field of 24 Hz.
