Reduktáza

Reduktáza, or reductase, is a general term for enzymes that catalyze reduction reactions, transferring electrons and often hydrogen atoms to substrates. Most reductases use NADH or NADPH as electron donors and belong to the larger oxidoreductase (EC 1) superfamily, with the exact enzyme commission (EC) number determined by the substrate and reaction.

Reductases play roles in many biological processes, including metabolism, steroid and hormone synthesis, lipid remodeling, and the detoxification of xenobiotics. They are widespread across bacteria, fungi, plants, and animals, and can influence the fate of drugs by altering their chemical form, thereby affecting efficacy and resistance.

Mechanism-wise, many reductases catalyze a hydride transfer from the donor cofactor (often NADPH) to the substrate, sometimes with accompanying protonation steps. Some enzymes use alternative electron donors or cofactors. Reactions typically involve reduction of functional groups such as carbonyls, nitro groups, or double bonds, producing more reduced compounds like alcohols or amines.

Major families include aldo-keto reductases (AKR) and short-chain dehydrogenase/reductase (SDR) enzymes, both NAD(P)H-dependent and involved in a wide range of substrates. Other reductase families include carbonyl reductases and various xenobiotic reductases, reflecting the diversity of substrates and biological contexts in which reductases operate.

See also: oxidoreductase; NADPH. Etymology: from Latin reductus "brought back" + -ase.