Which type of enzyme is responsible for catalyzing oxidation-reduction reactions?

• A. Hydrolase
• B. Transferase
• C. Oxidoreductase
• D. Isomerase

Answer: (C)

Oxidoreductases are the enzymes specifically responsible for catalyzing oxidation-reduction reactions, which involve the transfer of electrons between molecules. During these reactions, one molecule gets oxidized (loses electrons) while another gets reduced (gains electrons). This process is crucial in various biological pathways, including cellular respiration and photosynthesis, where energy transfer is essential for life.

Oxidoreductases can be recognized by their use of coenzymes like NAD+/NADH and FAD/FADH2, which participate in the electron transfer process. An example of an oxidoreductase is lactate dehydrogenase, which catalyzes the conversion of pyruvate to lactate while reducing NAD+ to NADH.

The other types of enzymes mentioned play different roles in metabolic processes. For instance, hydrolases catalyze the hydrolysis of chemical bonds, transferases are involved in transferring functional groups between molecules, and isomerases facilitate the rearrangement of atoms within a molecule. Each group of enzymes serves distinct functions, but it is the oxidoreductases that are specifically tasked with catalyzing oxidation-reduction reactions.