Anthocyanidin synthase from<i>Gerbera hybrida</i>catalyzes the conversion of (+)-catechin to cyanidin and a novel procyanidin
作者:Frank Wellmann、Markus Griesser、Wilfried Schwab、Stefan Martens、Wolfgang Eisenreich、Ulrich Matern、Richard Lukačin
DOI:10.1016/j.febslet.2006.02.004
日期:2006.3.6
Anthocyanidins were proposed to derive from (+)-naringenin via (2R,3R)-dihydroflavonol(s) and (2R,3S,4S)-leucocyanidin(s) which are eventually oxidized by anthocyanidin synthase (ANS). Recently, the role of ANS has been put into question, because the recombinant enzyme from Arabidopsis exhibited primarily flavonol synthase (FLS) activity with negligible ANS activity. This and other studies led to the
提出花色素苷通过(2R,3R)-二氢黄酮醇和(2R,3S,4S)-隐花色素从(+)-柚皮苷衍生,它们最终被花色素苷合酶(ANS)氧化。近来,ANS的作用受到质疑,因为来自拟南芥的重组酶主要表现出黄酮醇合酶(FLS)活性,而ANS活性可忽略不计。这项研究和其他研究提出了一个建议,即ANS和FLS可以选择带有“β面” C-3羟基的二氢类黄酮底物,并最初通过“α面”羟基化形成3-geminal二醇。非洲菊杂种重组ANS的分析完全支持该提议,并扩展至儿茶素和表儿茶素异构体,作为描述酶特异性的潜在底物。非洲菊ANS将(+)-儿茶素转化为两种主要产物和一种次要产物,而ent(-)-儿茶素(2S,3R-trans-儿茶素),(-)-表儿茶素,ent(+)-表儿茶素(2S,3S-不接受顺式-表儿茶素和(-)-没食子儿茶素。(+)-儿茶素的K(m)值在175 microM下测定,并且通过LC-MS(n)和N