Substrate specificity of an aflatoxin-metabolizing aldehyde reductase.
The enzyme from rat liver that reduces aflatoxin B1-dialdehyde exhibits a unique catalytic specificity distinct from that of other aldo-keto reductases. This enzyme, designated AFAR, displays high activity towards dicarbonyl-containing compounds with ketone groups on adjacent carbon atoms; 9,10-phenanthrenequinone, acenaphthenequinone and camphorquinone were found to be good substrates. Although AFAR can also reduce aromatic and aliphatic aldehydes such as succinic semialdehyde, it is inactive with glucose, galactose and xylose. The enzyme also exhibits low activity towards alpha,beta-unsaturated carbonyl-containing compounds. Determination of the apparent Km reveals that AFAR has highest affinity for 9,10-phenanthrenequinone and succinic semialdehyde, and low affinity for glyoxal and DL-glyceraldehyde.
Biomedical Research Centre, Ninewells Hospital and Medical School, University of Dundee, Scotland, U.K.
E M
EM
Ellis
J D
JD
Hayes
D000449:Aldehyde Reductase / Q000378:metabolism*; D000447:Aldehydes / Q000378:metabolism; D000818:Animals; D050260:Carbohydrate Metabolism; D003001:Cloning, Molecular; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006168:Guinea Pigs; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D051379:Mice; D051381:Rats; D011994:Recombinant Proteins / Q000378:metabolism; D013329:Structure-Activity Relationship; D013379:Substrate Specificity
D000447:Aldehydes; D004791:Enzyme Inhibitors; D011994:Recombinant Proteins; C082765:aflatoxin B1 aldehyde reductase; D000449:Aldehyde Reductase