Magnetic Properties of Reactive Oxygen Species and their Possible Role in Cancer Therapy

Spin-depending internal magnetic interactions in oxygen are crucial for the chemistry and photobiology of this molecule. Photosynthesis, respiration, and many other life-supporting oxygen reactions are governed by enzymes that use fine magnetic forces to overcome the spin-forbidden character of all aerobic metabolism. Life on Earth occurs on the border between combustion and oxidative phosphorylation, and this balance is largely dependent on reactive oxygen species. ROS can cause apoptosis or cell necrosis, and ROS also controls homeostasis through numerous signaling functions. Until recently, biochemists had not paid attention to internal magnetic interactions that influence the chemical activity of such ROS as superoxide ion, singlet oxygen, peroxynitrite, and many others. The role of superoxide dismutase, the oldest enzyme on the Earth, which provides superoxide concentration control, stresses the importance of the O2-• species as the precursor of many other ROS. Spin-orbit coupling in O2-• and O2 species are the main internal magnetic interactions that could influence cancer growth and be connected with cancer therapy.