Metabolism of oxidized linoleic acid: characterization of 13-hydroxyoctadecadienoic acid dehydrogenase activity from rat colonic tissue.
An oxidized derivative of linoleic acid, 13-hydroxyoctadecadienoic acid (13-HODE), is dehydrogenated by an NAD+ dependent dehydrogenase present in rat colon mucosa. The product of the reaction is the 2,4-dienone, 13-oxooctadecadienoic acid. Enzyme activity was determined by HPLC analysis of incubation mixtures as well as by measuring the increase in absorbance at 285 nm, which represents formation of the 2,4-dienone chromophore. Characteristics of the reaction with respect to protein concentration, time of incubation and substrate dependence were investigated. Several inhibitors of known dehydrogenases had no effect on the 13-HODE dehydrogenase. These include, ethanol, indomethacin, 6-methyl-17-hydroxyprogesterone acetate, 4-(diethylamino)-benzaldehyde, and aspirin. The enzyme was mildly inhibited by pyrazole, 4-methylpyrazole and ibuprofen. Disulfiram was found to be a potent inhibitor of enzyme activity with an IC50 of 200 microM. Inhibitor specificity, and other characteristics of the reaction suggest the enzyme is neither alcohol dehydrogenase, diol dehydrogenase, nor a prostaglandin dehydrogenase. It is possible this enzyme plays an important role in the response of the colonic mucosa to the mitogenic effect of oxidized fatty acids.
Earles
S M
SM
Department of Chemistry, Oakland University, Rochester, MI 48309-4401.
Bronstein
J C
JC
Winner
D L
DL
Bull
A W
AW
D000429:Alcohol Oxidoreductases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D003106:Colon / Q000187:drug effects / Q000201:enzymology*; D000431:Ethanol / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007413:Intestinal Mucosa / Q000187:drug effects / Q000201:enzymology*; D019787:Linoleic Acid; D008041:Linoleic Acids / Q000378:metabolism*; D008297:Male; D010084:Oxidation-Reduction; D051381:Rats; D011919:Rats, Inbred Strains
D008041:Linoleic Acids; D000431:Ethanol; C024348:13-hydroxy-9,11-octadecadienoic acid; D019787:Linoleic Acid; D000429:Alcohol Oxidoreductases; C067701:13-hydroxyoctadecadienoic acid dehydrogenase