Reduktaz

Reduktaz is a term used in biochemistry to denote enzymes that catalyze reduction reactions, i.e., the transfer of electrons to substrates. Most reduktazes rely on donors such as NADH or NADPH and belong to the broader family of oxidoreductases (EC class 1). The term encompasses many enzyme families with diverse substrates, including xenobiotics, steroids, sugars, and lipids. Notable members include quinone reductases such as NQO1, aldehyde and ketone reductases in the aldo-keto reductase (AKR) and short-chain dehydrogenase/reductase (SDR) superfamilies, nitroreductases, and azoreductases. Mechanistically, reduktazes often perform hydride transfer from NAD(P)H to the substrate; others use flavin cofactors (FMN or FAD) or metal ions to mediate electron transfer. Structurally, many contain Rossmann-like NAD(P)H-binding folds or flavin-dependent domains.

Reduktazes play essential roles in metabolism, detoxification, and redox balance. They participate in steroid and lipid metabolism, the biotransformation of xenobiotics, and the activation or deactivation of certain prodrugs. In humans and other organisms, altered reductase activity can influence susceptibility to drugs, oxidative stress, and cancer risk. Industrially, reduktazes are exploited as biocatalysts for stereoselective reductions in pharmaceutical synthesis and for bioremediation.

Examples include human NQO1 and various AKR enzymes such as AKR1B1 and AKR1C1–C4. See also oxidoreductases and reductases.