Nakayama T, Yonekura-Sakakibara K, Sato T, Kikuchi S, Fukui Y, Fukuchi-Mizutani M, Ueda T, Nakao M, Tanaka Y, Kusumi T, Nishino T
Department of Biomolecular Engineering, Graduate School of Engineering, Tohoku University, Aoba-yama 07, Sendai 980-8579, Japan.
Science. 2000 Nov 10;290(5494):1163-6. doi: 10.1126/science.290.5494.1163.
Aurones are plant flavonoids that provide yellow color to the flowers of some popular ornamental plants, such as snapdragon and cosmos. In this study, we have identified an enzyme responsible for the synthesis of aurone from chalcones in the yellow snapdragon flower. The enzyme (aureusidin synthase) is a 39-kilodalton, copper-containing glycoprotein catalyzing the hydroxylation and/or oxidative cyclization of the precursor chalcones, 2',4',6',4-tetrahydroxychalcone and 2',4',6',3,4-pentahydroxychalcone. The complementary DNA encoding aureusidin synthase is expressed in the petals of aurone-containing varieties. DNA sequence analysis revealed that aureusidin synthase belongs to the plant polyphenol oxidase family, providing an unequivocal example of the function of the polyphenol oxidase homolog in plants, i.e., flower coloration.
橙酮是一种植物类黄酮，能为一些常见观赏植物的花朵提供黄色，如金鱼草和大波斯菊。在本研究中，我们鉴定出一种负责在黄色金鱼草花中由查耳酮合成橙酮的酶。该酶（金黄素合成酶）是一种39千道尔顿的含铜糖蛋白，催化前体查耳酮（2',4',6',4-四羟基查耳酮和2',4',6',3,4-五羟基查耳酮）的羟基化和/或氧化环化反应。编码金黄素合成酶的互补DNA在含橙酮品种的花瓣中表达。DNA序列分析表明，金黄素合成酶属于植物多酚氧化酶家族，为多酚氧化酶同源物在植物中的功能，即花色形成，提供了一个明确的例子。
