More Superoxide Madness

One of the enzymes that handles superoxide is superoxide dismutase. Actually, this is a family of enzymes, using various metals as cofactors, which catalyze the dismutation of superoxide:

(1) M(n+1)+ − SOD + O2 → Mn+ − SOD + O2

(2) Mn+ − SOD + O2 + 2H+ → M(n+1)+ − SOD + H2O2.

where M = Cu (n=1) ; Mn (n=2) ; Fe (n=2) ; Ni (n=2).

I know, I know...your eyes just glazed over and your brain just went offline. Bottom line: superoxide production leads to the formation of hydrogen peroxide. That's bad enough, because peroxide is itself a radical that is not good for you. But through an iron-catalyzed process known as the Fenton reaction, peroxide can be converted to OH , the hydroxyl radical.

(1) Fe2+ + H2O2 → Fe3+ + OH + OH

(2) Fe3+ + H2O2 → Fe2+ + OOH + H+

Two molecules of hydrogen peroxide are converted into two hydroxyl radicals and water. The generated radicals then engage in secondary reactions. More electrons running loose.

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