Aldehyde oxidoreductase (AOR)

Aldehyde oxidoreductase (AOR) is a metalloenzyme that catalyzes the reversible oxidation of a wide range of aldehydes to their corresponding carboxylic acids, with reduction of electron acceptors such as NAD+ or viologen dyes. The best-characterized forms are tungsten-containing enzymes found in bacteria and archaea; in these, the enzyme comprises multiple subunits, including a tungsten-cofactor-containing catalytic subunit, ferredoxin-like electron transfer subunits, and sometimes an FAD cofactor-containing subunit mediating transfer to NAD+. AORs play an important role in the detoxification of aldehydes in anaerobic metabolism and have broad utility in biotechnology due to their stability, substrate range, and ability to participate in both oxidation and reduction reactions. The enzyme has no established direct medicinal use but is of significant interest for synthetic biology and biochemical engineering. Mammalian aldehyde oxidoreductases (commonly termed aldehyde oxidases) are structurally related but use molybdenum in the active site and are notable for their roles in the metabolism of xenobiotics and some therapeutic drugs[1][2][3][4][5][6].

Other names

AORAldehyde ferredoxin oxidoreductaseTungsten-containing aldehyde oxidoreductaseAldehyde oxidase

Catalyzes the oxidation of aldehydes (RCHO) to carboxylic acids (RCOOH) using a tungsten or molybdenum center, with transfer of electrons via iron–sulfur (Fe4S4) clusters and ferredoxin or NAD+ as electron acceptors. Some bacterial AORs can reduce carboxylic acids to aldehydes using molecular hydrogen as electron donor (reverse reaction). Mechanism involves nucleophilic attack by water, hydride transfer to the metal center, and subsequent electron transfer for regeneration of the active site.