An even faster example of catalysis is seen with the enzyme superoxide dismutase, which helps
to remove the toxic free radical anion superoxide, ·O2-, a by-product of
oxidative metabolism
Superoxide dismutase catalyzes the first step in a two-step reaction, in which 4 superoxide
radicals are converted to 2 molecules of O2 and 2 molecules of hydrogen peroxide (H2O2):
The enzyme uses a bound copper atom to remove the single electron, where the electron is used to
reduce the copper atom in one step, and then is released and transferred to product in the second step:
