What type of enzyme oxidizes a substrate by reducing an electron acceptor, typically NAD+ or FAD?

The enzyme that oxidizes a substrate by reducing an electron acceptor, typically NAD+ or FAD, is a dehydrogenase. Dehydrogenases catalyze oxidation-reduction (redox) reactions where they facilitate the removal of hydrogen atoms (or electrons) from a substrate, ultimately leading to the reduction of an electron acceptor molecule like NAD+ or FAD.

In this process, the substrate is oxidized—meaning it loses electrons and/or hydrogen—while the electron acceptor (NAD+ or FAD) gains those electrons and becomes reduced to NADH or FADH2. This transfer of electrons is crucial in metabolic pathways, particularly in cellular respiration and fermentation, where the energy from oxidized substrates is captured to produce ATP.

Understanding this function clarifies the role of dehydrogenases in metabolic processes, as they help to drive reactions that are foundational to energy production in living systems. Other types of enzymes, such as kinases, lyases, and ligases, serve different functions and do not engage primarily in the oxidation of substrates via electron transfer.