The specificity of alcohol dehydrogenase with cis-retinoids. Activity with 11-cis-retinol and localization in retina.
The specificity of alcohol dehydrogenase with cis-retinoids. Activity with 11-cis-retinol and localization in retina.
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乙醇脱氢酶与顺式视黄醇的特异性。
DOI：
10.1111/j.1432-1033.2004.04058.x
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
Parés,Xavier
中科院分区：
文献类型：
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作者：
Martras,Sílvia;Alvarez,Rosana;Martínez,SusanaE;Torres,Dámaso;Gallego,Oriol;Duester,Gregg;Farrés,Jaume;deLera,AngelR;Parés,Xavier
在基因敲除小鼠中的研究支持醇脱氢酶ADH 1和ADH 4参与类维生素A代谢，尽管对小鼠酶的类维生素A动力学尚不清楚。此外，由于缺乏关于11-顺式-维甲酸动力学的信息，无法确定醇脱氢酶（ADH）在眼维甲酸相互转化中的作用。本文报告了人ADH 1B 1、ADH 1B 2、ADH 4和小鼠ADH 1和ADH 4与视黄醇和视黄醛的全反式、7顺式、9顺式、11顺式和13顺式异构体的动力学。这些类维生素A是所有测试酶的底物，除了不被ADH 1使用的13-顺式异构体。一般来说，人类和小鼠ADH 4表现出相似的活性，高于ADH 1，而小鼠ADH 1比同源的人类酶更有效。所有测试的ADH都有效地使用11-cis-维甲酸。ADH 4对11-cis-视黄醇氧化的kcat/Km值远高于11-cis-视黄醇还原的kcat/Km值，这是哺乳动物ADH对任何醇/醛底物对的独特性质。对接模拟和人ADH 4 M141 L突变体的动力学性质表明，在活性位点的中间区域的残基141对于这种ADH 4特异性是必需的。 ADH 4与11-cis-视黄醇的独特动力学，其与视黄醇异构体的广泛特异性及其在几个视网膜细胞层（包括色素上皮）中的免疫定位，支持这种酶在视网膜中发生的各种视黄醇氧化中的作用。胞浆ADH 4活性可能补充参与色素再生和视黄酸合成的异构体特异性微粒体酶。
Studies in knockout mice support the involvement of alcohol dehydrogenases ADH1 and ADH4 in retinoid metabolism, although kinetics with retinoids are not known for the mouse enzymes. Moreover, a role of alcohol dehydrogenase (ADH) in the eye retinoid interconversions cannot be ascertained due to the lack of information on the kinetics with 11‐cis‐retinoids. We report here the kinetics of human ADH1B1, ADH1B2, ADH4, and mouse ADH1 and ADH4 with all‐trans‐, 7‐cis‐, 9‐cis‐, 11‐cis‐ and 13‐cis‐isomers of retinol and retinal. These retinoids are substrates for all enzymes tested, except the 13‐cisisomers which are not used by ADH1. In general, human and mouse ADH4 exhibit similar activity, higher than that of ADH1, while mouse ADH1 is more efficient than the homologous human enzymes. All tested ADHs use 11‐cis‐retinoids efficiently. ADH4 shows much higherkcat/Kmvalues for 11‐cis‐retinol oxidation than for 11‐cis‐retinal reduction, a unique property among mammalian ADHs for any alcohol/aldehyde substrate pair. Docking simulations and the kinetic properties of the human ADH4 M141L mutant demonstrated that residue 141, in the middle region of the active site, is essential for such ADH4 specificity. The distinct kinetics of ADH4 with 11‐cis‐retinol, its wide specificity with retinol isomers and its immunolocalization in several retinal cell layers, including pigment epithelium, support a role of this enzyme in the various retinol oxidations that occur in the retina. Cytosolic ADH4 activity may complement the isomer‐specific microsomal enzymes involved in photopigment regeneration and retinoic acid synthesis.