Lactate dehydrogenase belongs to which class of enzymes?

Lactate dehydrogenase belongs to which class of enzymes?

• A. Isomerases
• B. Ligases
• C. Oxidoreductases
• D. Transferases

Answer: (C)

Oxidoreductases catalyze oxidation–reduction reactions, where electrons are transferred between molecules. Lactate dehydrogenase fits this class because it uses NADH to reduce pyruvate to lactate; NADH is oxidized to NAD+, while pyruvate gains electrons to become lactate. This redox process is the defining feature of oxidoreductases. The other enzyme classes involve different chemistry: isomerases rearrange atoms within a molecule, ligases join two molecules using ATP, and transferases move functional groups from one molecule to another. So the activity of transferring electrons in a redox couple makes lactate dehydrogenase an oxidoreductase.

Oxidoreductases catalyze oxidation–reduction reactions, where electrons are transferred between molecules. Lactate dehydrogenase fits this class because it uses NADH to reduce pyruvate to lactate; NADH is oxidized to NAD+, while pyruvate gains electrons to become lactate. This redox process is the defining feature of oxidoreductases. The other enzyme classes involve different chemistry: isomerases rearrange atoms within a molecule, ligases join two molecules using ATP, and transferases move functional groups from one molecule to another. So the activity of transferring electrons in a redox couple makes lactate dehydrogenase an oxidoreductase.