Katsuyama Yohei, Kita Tomoko, Funa Nobutaka, Horinouchi Sueharu
Department of Biotechnology, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan.
J Biol Chem. 2009 Apr 24;284(17):11160-70. doi: 10.1074/jbc.M900070200. Epub 2009 Mar 3.
Curcuminoids found in the rhizome of turmeric, Curcuma longa, possess various biological activities. Despite much attention regarding the biosynthesis of curcuminoids because of their pharmaceutically important properties and biosynthetically intriguing structures, no enzyme systems have been elucidated. Here we propose a pathway for curcuminoid biosynthesis in the herb C. longa, which includes two novel type III polyketide synthases. One of the type III polyketide synthases, named diketide-CoA synthase (DCS), catalyzed the formation of feruloyldiketide-CoA by condensing feruloyl-CoA and malonyl-CoA. The other, named curcumin synthase (CURS), catalyzed the in vitro formation of curcuminoids from cinnamoyldiketide-N-acetylcysteamine (a mimic of the CoA ester) and feruloyl-CoA. Co-incubation of DCS and CURS in the presence of feruloyl-CoA and malonyl-CoA yielded curcumin at high efficiency, although CURS itself possessed low activity for the synthesis of curcumin from feruloyl-CoA and malonyl-CoA. These findings thus revealed the curcumin biosynthetic route in turmeric, in which DCS synthesizes feruloyldiketide-CoA, and CURS then converts the diketide-CoA esters into a curcuminoid scaffold.
姜黄（Curcuma longa）根茎中含有的姜黄素类化合物具有多种生物活性。尽管由于其药学上的重要特性和生物合成方面引人关注的结构，姜黄素类化合物的生物合成受到了广泛关注，但尚未阐明任何酶系统。在此，我们提出了一种在草本植物姜黄中姜黄素类化合物的生物合成途径，该途径包括两种新型的III型聚酮合酶。其中一种III型聚酮合酶名为二酮辅酶A合酶（DCS），它通过缩合阿魏酰辅酶A和丙二酰辅酶A催化形成阿魏酰二酮辅酶A。另一种名为姜黄素合酶（CURS），它催化从肉桂酰二酮-N-乙酰半胱氨酸（辅酶A酯的类似物）和阿魏酰辅酶A体外形成姜黄素类化合物。在阿魏酰辅酶A和丙二酰辅酶A存在的情况下，DCS和CURS共同孵育可高效产生姜黄素，尽管CURS本身从阿魏酰辅酶A和丙二酰辅酶A合成姜黄素的活性较低。因此，这些发现揭示了姜黄中姜黄素的生物合成途径，其中DCS合成阿魏酰二酮辅酶A，然后CURS将二酮辅酶A酯转化为姜黄素类化合物骨架。
