title: Enzymatic characteristics of an aldo-keto reductase family protein (AKR1C15) and its localization in rat tissues.
abstract: A member of the aldo-keto reductase superfamily, AKR1C15, was isolated via cDNA cloning, but its physiological function remains unknown. Here, we show that recombinant AKR1C15 is an NADPH-dependent reductase with broad substrate specificity for aromatic, alicyclic and aliphatic carbonyl compounds, including acetoin, 2,5-hexanedione, methylglyoxal, farnesal, retinals, 17-ketosteroids and monosaccharides. Especially, all-trans-retinal, alpha-diketones and lipid-derived aldehydes including 4-hydroxynonenal were excellent substrates showing low K(m) values (0.3-5.5 microM). Immunohistochemical and reverse transcription-PCR analyses revealed that AKR1C15 is highly expressed in rat bronchiolar Clara cells, type II alveolar cells, gastric parietal cells, the epithelial cells of the stomach and colon, and the brown adipocytes. The enzyme was not detected in cells of other rat tissues, but is consistently expressed in the vascular endothelial cells. These results suggest that AKR1C15 plays a role in retinoid, steroid, isoprenoid and carbohydrate metabolism, as well as a defense system, protecting against reactive carbonyl compounds.
authors.affiliation: Laboratory of Biochemistry, Gifu Pharmaceutical University, Mitahora-higashi, Gifu 502-8585, Japan. sendo@gifu-pu.ac.jp
authors.forename: Satoshi
authors.initials: S
authors.lastname: Endo
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Matsunaga
authors.forename: Kenji
authors.initials: K
authors.lastname: Horie
authors.forename: Kazuo
authors.initials: K
authors.lastname: Tajima
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Bunai
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Carbone
authors.forename: Ossama
authors.initials: O
authors.lastname: El-Kabbani
authors.forename: Akira
authors.initials: A
authors.lastname: Hara
mesh_terms: D000429:Alcohol Oxidoreductases / Q000737:chemistry* / Q000378:metabolism*; D000449:Aldehyde Reductase; D000074408:Aldo-Keto Reductases; D000818:Animals; D004789:Enzyme Activation; D004795:Enzyme Stability; D005260:Female; D008297:Male; D009928:Organ Specificity; D051381:Rats; D017208:Rats, Wistar; D014018:Tissue Distribution
chemical_list: D000429:Alcohol Oxidoreductases; D000074408:Aldo-Keto Reductases; D000449:Aldehyde Reductase