To study the effects of extremely low frequency electromagnetic fields on membrane F0F1-ATPase enzyme activity in chromatophore suspensions (as a possible initial step in a cascade of events that could affect health).
F0F1-ATPase is composed of two parts, membrane-embedded part F0 and hydrophilic catalytic part F1. F0F1-ATPase interconverts two major "energy currencies" (the transmembrane electrochemical potential difference of protons and ATP).
F0F1-ATPases were also treated with N,N-dicyclohexylcarbodiimide (DCCD, for inhibition of subunit F0) and lithium chloride (also for hydrolysis inhibition). Additionally, the chromatophores were labeled with the pH indicator F-DHPE (proton transfer experiment (function of F0 is the proton transfer)).
60 Hz magnetic fields enhanced the enzyme activity of F0F1-ATPase. The effects depended on magnetic intensity: 0.3 and 0.5 mT magnetic fields enhanced the hydrolysis activity, whereas 0.1 mT exposure caused no significant changes. The magnetic fields mainly affected the subunit F1: even if the F0F1-ATPase was inhibited by DCCD (inhibition of F0), its hydrolysis activity was enhanced by a 0.5 mT magnetic field. Moreover, when the F-DHPE-labeled chromatophores were exposed to 0.5 mT, it was found that the pH of the outer membrane of the chromatophore was unchanged.
The data may provide a new way to explore a relationship between the effects of magnetic fields on human health and the effects of magnetic fields on membrane F0F1-ATPase (F1 may be the target affected by magnetic fields).