Reduktaasi

Reduktaasi, or reductase, is a broad term for enzymes that catalyze reduction reactions in which substrates gain electrons. In biochemistry, reductases are typically a subset of oxidoreductases (EC class 1) and often use cofactors such as NADPH, NADH, FAD, or FMN to donate electrons. They play key roles in metabolism, biosynthesis, and detoxification by converting carbonyl compounds, nitro groups, or unsaturated bonds into more reduced forms.

Common reductase families include aldo-keto reductases (AKRs), which reduce carbonyl groups to corresponding alcohols, and the short-chain dehydrogenase/reductase (SDR) superfamily, which catalyzes a wide range of redox reactions using NAD(P)H. Other notable groups are nitro- and azoreductases, which reduce nitro and azo functional groups, and enone reductases that saturate double bonds. Many reductases function in a directionally biased manner under cellular conditions, often influenced by the availability of cofactors and the redox state of the cell.

Cofactor dependence varies among reductases. The majority use NADPH as a primary electron donor in anabolic or detoxification pathways, while some rely on NADH for catabolic or energy-related processes. Flavin cofactors (FAD or FMN) or other prosthetic groups may also participate in the electron transfer mechanism.

Biological and practical significance is broad. In humans, reductases participate in steroid metabolism, xenobiotic detoxification, and maintenance of redox balance. In microbes and plants, they enable pollutant degradation, biosynthesis of valuable compounds, and resistance to stress. Reductases are targets in drug development, metabolic engineering, and industrial biotransformations.