Rabbit 3-hydroxyhexobarbital dehydrogenase is a NADPH-preferring reductase with broad substrate specificity for ketosteroids, prostaglandin D2, and other endogenous and xenobiotic carbonyl compounds
Rabbit 3-hydroxyhexobarbital dehydrogenase is a NADPH-preferring reductase with broad substrate specificity for ketosteroids, prostaglandin D2, and other endogenous and xenobiotic carbonyl compounds
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兔 3-羟基己巴比妥脱氢酶是一种 NADPH 偏好还原酶，对酮类固醇、前列腺素 D2 和其他内源性和外源性羰基化合物具有广泛的底物特异性
DOI：
10.1016/j.bcp.2013.08.024
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
and Akira Hara
中科院分区：
文献类型：
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作者：
Satoshi Endo;Toshiyuki Matsunaga;Atsuko Matsumoto;Yuki Arai;Satoshi Ohno;Ossama El-Kabbani;Kazuo Tajima;Yukio Kitade;Yasuo Bunai;Shigeru Yamano;and Akira Hara
3-羟基己巴比妥脱氢酶 (3HBD) 催化 NAD(P)+ 连接的 3-羟基己巴比妥氧化成 3-氧代己巴比妥。该酶被认为是异生醇和一些羟基类固醇的脱氢酶，但其生理功能仍然未知。我们纯化了兔3HBD，分离了其cDNA，并检查了其对辅酶和底物的特异性、反应方向性和组织分布。 3HBD 是醛酮还原酶 (AKR) 超家族的成员 (AKR1C29)，在生理 pH 值为 7.4 时，对 NADP(H) 表现出对 NADP(H) 的高度偏好，而不是 NAD(H)。在NADPH相关的还原中，3HBD对多种醌、酮和醛表现出广泛的底物特异性，包括3-、17-和20-酮类固醇和前列腺素D2，它们分别转化为3α-、17β-和20α-羟基类固醇和9α,11β-前列腺素F2。特别是，α-二酮（如靛红和二乙酰）和脂质过氧化衍生的醛（如 4-氧代-和 4-羟基-2-壬烯醛）是表现出低 Km 值 (0.1–5.9 μM) 的优异底物。在3HBD过表达的细胞中，3-氧代己巴比妥和5β-雄甾烷-3α-ol-17-one分别代谢为3-羟基己巴比妥和5β-雄甾烷-3α,17β-二醇，但逆反应没有进行。该酶在细胞中的过度表达降低了 4-oxo-2-nonenal 的细胞毒性。 3HBD 的 mRNA 在兔组织中普遍表达。结果表明，3HBD 是一种偏爱 NADPH 的还原酶，在类固醇、前列腺素 D2、碳水化合物和异生物质的代谢以及防御系统中发挥作用，防止反应性羰基化合物的侵害。
3-Hydroxyhexobarbital dehydrogenase (3HBD) catalyzes NAD(P)+-linked oxidation of 3-hydroxyhexobarbital into 3-oxohexobarbital. The enzyme has been thought to act as a dehydrogenase for xenobiotic alcohols and some hydroxysteroids, but its physiological function remains unknown. We have purified rabbit 3HBD, isolated its cDNA, and examined its specificity for coenzymes and substrates, reaction directionality and tissue distribution. 3HBD is a member (AKR1C29) of the aldo-keto reductase (AKR) superfamily, and exhibited high preference for NADP(H) over NAD(H) at a physiological pH of 7.4. In the NADPH-linked reduction, 3HBD showed broad substrate specificity for a variety of quinones, ketones and aldehydes, including 3-, 17- and 20-ketosteroids and prostaglandin D2, which were converted to 3α-, 17β- and 20α-hydroxysteroids and 9α,11β-prostaglandin F2, respectively. Especially, α-diketones (such as isatin and diacetyl) and lipid peroxidation-derived aldehydes (such as 4-oxo- and 4-hydroxy-2-nonenals) were excellent substrates showing lowKmvalues (0.1–5.9 μM). In 3HBD-overexpressed cells, 3-oxohexobarbital and 5β-androstan-3α-ol-17-one were metabolized into 3-hydroxyhexobarbital and 5β-androstane-3α,17β-diol, respectively, but the reverse reactions did not proceed. The overexpression of the enzyme in the cells decreased the cytotoxicity of 4-oxo-2-nonenal. The mRNA for 3HBD was ubiquitously expressed in rabbit tissues. The results suggest that 3HBD is an NADPH-preferring reductase, and plays roles in the metabolisms of steroids, prostaglandin D2, carbohydrates and xenobiotics, as well as a defense system, protecting against reactive carbonyl compounds.