Question

hich of the following statements about the superoxide dismutase mechanism is correct? two electrons are accepted by superoxide dismutase upon superoxide reduction to produce hydrogen peroxide. the initial and the final steps of the mechanism produce oxidized superoxide dismutase. the conversion of two superoxide radical anions by superoxide dismutase yields two protons. a superoxide radical anion plays the role of the oxidant and reductant in different steps of the mechanism.

Answer 1

The correct statement about superoxide dismutase (SOD) is that a superoxide radical anion acts as both an oxidant and reductant during the enzyme's reaction cycle, which turns two superoxide radicals into hydrogen peroxide and oxygen. The enzyme is re-oxidized at the end of the reaction cycle.

Step-by-step explanation:

Superoxide dismutase (SOD) is an enzyme that safeguards cells against the damaging effects of superoxide radicals by converting them into oxygen and hydrogen peroxide.

The enzyme functions by catalyzing the dismutation reaction of two superoxide radicals, which involves the transfer of an electron from one superoxide radical to another, producing oxygen and hydrogen peroxide, as shown in the reaction: 2O₂⁻ + 2H+ → H₂O₂ + O₂

During the reaction, one superoxide radical is reduced to form hydrogen peroxide, while the other is oxidized to release oxygen.

It's noteworthy that this reaction also leads to the release of protons, which further ensure the maintenance of a pH balance within the cell. The SOD enzyme exists in oxidized form at the beginning and is re-oxidized at the end of the reaction cycle, ready to accept new superoxide radicals.