Human aldo-keto reductases: Function, gene regulation, and single nucleotide polymorphisms.
Aldo-keto reductases (AKRs) are a superfamily of NAD(P)H linked oxidoreductases that are generally monomeric 34-37kDa proteins present in all phyla. The superfamily consists of 15 families, which contains 151 members (www.med.upenn.edu/akr). Thirteen human AKRs exist that use endogenous substrates (sugar and lipid aldehydes, prostaglandins, retinals and steroid hormones), and in many instances they regulate nuclear receptor signaling. Exogenous substrates include metabolites implicated in chemical carcinogenesis: NNK (4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone), polycyclic aromatic hydrocarbon trans-dihydrodiols, and aflatoxin dialdehyde. Promoter analysis of the human genes identifies common elements involved in their regulation which include osmotic response elements, anti-oxidant response elements, xenobiotic response elements, AP-1 sites and steroid response elements. The human AKRs are highly polymorphic, and in some instances single nucleotide polymorphisms (SNPs) of high penetrance exist. This suggests that there will be inter-individual variation in endogenous and xenobiotic metabolism which in turn affect susceptibility to nuclear receptor signaling and chemical carcinogenesis.
Penning
Trevor M
TM
Center of Excellence in Environmental Toxicology, Department of Pharmacology, University of Pennsylvania School of Medicine, 130 C John Morgan Bldg., 3620 Hamilton Walk, Philadelphia, PA 19104-6084, USA. penning@pharm.med.upenn.edu
Drury
Jason E
JE
D000429:Alcohol Oxidoreductases / Q000502:physiology*; D000449:Aldehyde Reductase; D000074408:Aldo-Keto Reductases; D002273:Carcinogens / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology*; D006801:Humans; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism*
D002273:Carcinogens; D017382:Reactive Oxygen Species; D018160:Receptors, Cytoplasmic and Nuclear; D000429:Alcohol Oxidoreductases; D000074408:Aldo-Keto Reductases; D000449:Aldehyde Reductase