Bouvier F, Hugueney P, d'Harlingue A, Kuntz M, Camara B
Institut de Biologie Moléculaire des Plantes du CNRS, Université Louis Pasteur, Strasbourg, France.
Plant J. 1994 Jul;6(1):45-54. doi: 10.1046/j.1365-313x.1994.6010045.x.
The late steps of carotenoid biosynthesis in plants involve the formation of xanthophylls. Little is known about the enzymology of these steps. This paper reports the purification to homogeneity of a xanthophyll biosynthetic enzyme from Capsicum annuum chromoplasts, which catalyzes the conversion of the ubiquitous 5,6-epoxycarotenoids, antheraxanthin and violaxanthin, into capsanthin and capsorubin, respectively. Owing to its bifunctionality, the name capsanthin-capsorubin synthase is proposed for this new enzyme. The purified enzyme is a monomer with a molecular mass of 50 kDa. Antibodies raised against this enzyme allowed the isolation of a full-length cDNA clone encoding a capsanthin capsorubin synthase high molecular weight precursor. The primary deduced structure reveals the presence of a consensus nucleotide binding site. The capsanthin-capsorubin synthase gene is specifically expressed during chromoplast development in fruits accumulating ketocarotenoids, but not in mutants impaired in this biosynthetic step.
植物中类胡萝卜素生物合成的后期步骤涉及叶黄素的形成。关于这些步骤的酶学知之甚少。本文报道了从辣椒质体中纯化出一种叶黄素生物合成酶，该酶催化普遍存在的5,6-环氧类胡萝卜素（花药黄质和堇菜黄质）分别转化为辣椒红素和辣椒玉红素。由于其具有双功能性，因此为这种新酶提议命名为辣椒红素-辣椒玉红素合酶。纯化后的酶是一种分子量为50 kDa的单体。针对该酶产生的抗体使得能够分离出一个编码辣椒红素-辣椒玉红素合酶高分子量前体的全长cDNA克隆。初步推导的结构显示存在一个共有核苷酸结合位点。辣椒红素-辣椒玉红素合酶基因在积累酮类胡萝卜素的果实的质体发育过程中特异性表达，但在该生物合成步骤受损的突变体中不表达。
