Earles S M, Bronstein J C, Winner D L, Bull A W
Department of Chemistry, Oakland University, Rochester, MI 48309-4401.
Biochim Biophys Acta. 1991 Jan 28;1081(2):174-80. doi: 10.1016/0005-2760(91)90023-b.
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.
亚油酸的一种氧化衍生物，13-羟基十八碳二烯酸（13-HODE），可被大鼠结肠黏膜中存在的一种依赖NAD⁺的脱氢酶脱氢。反应产物是2,4-二烯酮，13-氧代十八碳二烯酸。通过对孵育混合物进行HPLC分析以及测量285nm处吸光度的增加来测定酶活性，285nm处吸光度的增加代表2,4-二烯酮发色团的形成。研究了该反应在蛋白质浓度、孵育时间和底物依赖性方面的特性。几种已知脱氢酶的抑制剂对13-HODE脱氢酶没有影响。这些抑制剂包括乙醇、吲哚美辛、6-甲基-17-羟基孕酮乙酸酯、4-（二乙氨基）苯甲醛和阿司匹林。该酶受到吡唑、4-甲基吡唑和布洛芬的轻度抑制。发现双硫仑是酶活性的有效抑制剂，IC50为200μM。抑制剂特异性以及反应的其他特性表明该酶既不是乙醇脱氢酶、二醇脱氢酶，也不是前列腺素脱氢酶。这种酶可能在结肠黏膜对氧化脂肪酸促有丝分裂作用的反应中起重要作用。
