The inhibitory effect of [Cu.sup.2+] seen here could be due to direct binding to ALP (like [Hg.sup.2+]); however, due to the redox cycling
nature of [Cu.sup.2+], it is possible that some redox reactions involving the enzyme may be involved as well.
Although qui none species that undergo redox cycling
can generate ROS in cell-free aqueous environments (Le et aI.
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
Reduced Hcy may cause redox cycling
and disulfide interchange with other thiols, preferably cyst(e)ine, thus interfering with disulfide bonds.
Jeffries et al., "Redox cycling
of phenol induces oxidative stress in human epidermal keratinocytes," Journal of Investigative Dermatology, vol.
When exposed to hydrogen peroxide or the redox cycling
agent paraquat, DJ-1 undergoes an acidic pI shift (from 6.2 to 5.81 (Canet-Aviles et al.