reductasen

Reductases are enzymes that catalyze reduction reactions, the gain of electrons by a substrate. They are a subset of oxidoreductases (EC 1) that utilize cofactors such as NADH, NADPH, FAD, or FMN, sometimes ferredoxin, to transfer electrons.

They participate in diverse metabolic pathways including biosynthesis of nucleotides, lipids, amino acids, and in detoxification processes. In humans, examples include dihydrofolate reductase (DHFR) which reduces dihydrofolate to tetrahydrofolate, and glutathione reductase which reduces glutathione disulfide to the thiol form, maintaining cellular redox balance. In microorganisms, nitroreductases and azoreductases reduce nitro and azo compounds, often involved in xenobiotic metabolism.

Mechanistically, many reductases use flavin cofactors (FAD or FMN) or metal centers to shuttle electrons, whereas others transfer electrons directly from NADPH to the substrate. Some reductases are highly specific for substrate; others have broad substrate ranges.

Applications: In biotechnology and industry, reductases are used for chiral synthesis and biocatalysis; in medicine, alterations in reductase function can impact drug activation, resistance, and disease.

Etymology and naming: The plural form "reductases" in English; in German "Reduktasen" or "Reduktase" depending; in German the singular "Reduktase". In enzymology, many enzymes designated as reductases belong to the broader class of oxidoreductases (EC 1).