This is not surprising as UV radiation only works with redox cycling
heavy metals to produce oxy-radicals .
PQQ's powerful redox cycling
abilities help it to chemically modify receptors for the most potent excitotoxic neurotransmitter, known as NMDA (N-Methyl-D-aspartic acid).
Nitric oxide synthases catalyze the activation of redox cycling
and bioreductive anticancer agents.
It may be assumed that interactions with transition metal ions could be important in the regenerating liver since hepatectomy induces early redistribution of iron from the spleen and thymus into the tissue of regenerating liver  but also enhances oxygen delivery to the cells, necessary for the oxidative activation of phenolics via the redox cycling
2+], a transition metal incapable of producing ROS by redox cycling
, induces [H.
quinone, metal complexes, ArNO2, or conjugated iminium), either per se or as metabolites; such entities potentially give rise to reactive oxygen species (ROS) by redox cycling
When exposed to hydrogen peroxide or the redox cycling
agent paraquat, DJ-1 undergoes an acidic pI shift (from 6.