Misawa N, Kajiwara S, Kondo K, Yokoyama A, Satomi Y, Saito T, Miki W, Ohtani T
Central Laboratories for Key Technology, Kirin Brewery Co., Ltd., Kanagawa, Japan.
Biochem Biophys Res Commun. 1995 Apr 26;209(3):867-76. doi: 10.1006/bbrc.1995.1579.
Compounds that include (a) keto group(s) in a molecule are ubiquitous natural components. A novel gene involved in ketocompound biosynthesis, designated crtW, was isolated from the marine bacteria Agrobacterium aurantiacum and Alcaligenes PC-1 that produce ketocarotenoids such as astaxanthin. When this gene was introduced into Escherichia coli that accumulated beta-carotene due to the Erwinia carotenogenic genes, the E. coli transformants synthesized canthaxanthin, one of ketocarotenoids, which was identified after purification by its visible, FD-MS and 1H-NMR spectral analysis. It has been demonstrated for the first time that one gene encodes an enzyme "ketolase" that catalyzes the conversion of methylene groups of a hydrocarbon beta-carotene to keto groups for synthesizing canthaxanthin via echinenone.
分子中包含一个或多个酮基的化合物是普遍存在的天然成分。从产虾青素等酮类胡萝卜素的海洋细菌橙色土壤杆菌和产碱杆菌PC-1中分离出了一个参与酮类化合物生物合成的新基因，命名为crtW。当将该基因导入因欧文氏菌产类胡萝卜素基因而积累β-胡萝卜素的大肠杆菌中时，大肠杆菌转化体合成了酮类胡萝卜素之一的角黄素，通过可见光谱、FD-MS和1H-NMR光谱分析纯化后得以鉴定。首次证明一个基因编码一种“酮化酶”，该酶催化烃类β-胡萝卜素的亚甲基转化为酮基，从而通过海胆酮合成角黄素。
