A Nomenclature System for the Aldo-Keto Reductase Superfamily

The aldo-keto reductases (AKRs) represent a growing superfamily of oxidoreductases (Bohren et al., 1989; Bruce et al., 1994). Proteins of the AKR superfamily are monomeric (α/β)8-barrel proteins, about 320 amino acids in length, which bind NAD(P)(H) without a Rossmann-fold motif (Rondeau et al., 1992; Wilson et al., 1992 > 1995; Hoog et al., 1994, El-Kabbani et al., 1995). Found in mammals, amphibians, plants, yeast, protozoa, and bacteria, the AKRs metabolize a range of substrates including aliphatic aldehydes, monosaccharides, steroids, prostaglandins, polycyclic aromatic hydrocarbons, and isoflavinoid phytoalexins. To date, at least thirty-nine proteins have been cloned and characterized as members of the superfamily, and additional genes have been identified that potentially code for AKR proteins. The rapid progress in identifying new AKRs has lead to some problem in the naming of these proteins.