Which enzyme class is responsible for catalyzing redox reactions?

The correct choice is the class of enzymes known as oxidoreductases. These enzymes are specifically responsible for facilitating redox reactions, which involve the transfer of electrons between molecules. In these reactions, one molecule is oxidized (loses electrons) while the other is reduced (gains electrons).

Oxidoreductases play a crucial role in various biological processes, including cellular respiration, where they help in the transfer of electrons in the electron transport chain, as well as in metabolism where they assist in both the oxidation of substrates and the reduction of coenzymes such as NAD+ to NADH. This electron transfer is fundamental to energy production in the cell.

In contrast, the other enzyme classes do not focus on redox reactions. Transferases are involved in transferring functional groups from one molecule to another, hydrolases catalyze the hydrolysis of bonds (often using water), and isomerases are responsible for rearranging the structure of a molecule without altering its molecular formula. Each of these classes has its distinct function, highlighting the specialized nature of oxidoreductases in facilitating redox processes.