Tian Li, DellaPenna Dean
Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA.
Arch Biochem Biophys. 2004 Oct 1;430(1):22-9. doi: 10.1016/j.abb.2004.02.003.
The dihydroxy xanthophylls lutein (beta,epsilon-carotene-3,3'-diol) and zeaxanthin (beta,beta-carotene-3,3'-diol) are well known for their critical roles in photosystem structure and adaptation of plants to high light stress. As a group, carotenoid hydroxylases catalyze the formation of lutein and zeaxanthin from their corresponding cyclic carotene precursors. Carotenoid beta-ring hydroxylases (beta-hydroxylases) have been isolated and characterized from various organisms and have invariably been shown to be non-heme di-iron monooxygenases. The presence of an epsilon-ring specific hydroxylase (epsilon-hydroxylase) was genetically demonstrated by isolation of mutants at the LUT1 locus in Arabidopsis. This review focuses on progress in understanding the molecular and biochemical nature of the epsilon-hydroxylase and the in vivo overlapping functions of the various carotenoid beta- and epsilon-hydroxylases in Arabidopsis.
二羟基叶黄素，即叶黄素（β,ε-胡萝卜素-3,3'-二醇）和玉米黄质（β,β-胡萝卜素-3,3'-二醇），因其在光系统结构以及植物适应高光胁迫方面的关键作用而闻名。作为一个酶类群体，类胡萝卜素羟化酶催化由相应的环状类胡萝卜素前体形成叶黄素和玉米黄质。类胡萝卜素β-环羟化酶（β-羟化酶）已从多种生物体中分离并鉴定出来，且无一例外地被证明是非血红素双铁单加氧酶。通过分离拟南芥LUT1基因座的突变体，从遗传学角度证明了ε-环特异性羟化酶（ε-羟化酶）的存在。本综述重点关注在理解ε-羟化酶的分子和生化性质以及拟南芥中各种类胡萝卜素β-羟化酶和ε-羟化酶在体内的重叠功能方面所取得的进展。
