Oguro Satoshi, Akashi Tomoyoshi, Ayabe Shin-Ichi, Noguchi Hiroshi, Abe Ikuro
School of Pharmaceutical Sciences, and the 21st Century COE Program, University of Shizuoka, 52-1 Yada, Shizuoka 422-8526, Japan.
Biochem Biophys Res Commun. 2004 Dec 10;325(2):561-7. doi: 10.1016/j.bbrc.2004.10.057.
Recombinant chalcone synthase (CHS) from Scutellaria baicalensis accepted cinnamoyl diketide-NAC and cinnamoyl-NAC as a substrate, and carried out sequential condensations with malonyl-CoA to produce 2',4',6'-trihydroxychalcone. Steady-state kinetic analysis revealed that the CHS accepted the diketide-NAC with less efficiency, while cinnamoyl-NAC primed the enzyme reaction almost as efficiently as cinnamoyl-CoA. On the other hand, it was for the first time demonstrated that the diketide-NAC was also a substrate for recombinant polyketide reductase (PKR) from Glycyrrhiza echinata, and converted to the corresponding beta-ketohemithioester. Furthermore, by co-action of the CHS and the PKR, the NAC-thioesters were converted to 6'-deoxychalcone in the presence of NADPH and malonyl-CoA.
来自黄芩的重组查尔酮合酶（CHS）以肉桂酰二酮-NAC和肉桂酰-NAC作为底物，并与丙二酰辅酶A进行连续缩合反应生成2',4',6'-三羟基查尔酮。稳态动力学分析表明，CHS对二酮-NAC的接受效率较低，而肉桂酰-NAC引发酶反应的效率几乎与肉桂酰辅酶A相同。另一方面，首次证明二酮-NAC也是来自光果甘草的重组聚酮还原酶（PKR）的底物，并转化为相应的β-酮半硫酯。此外，通过CHS和PKR的共同作用，在NADPH和丙二酰辅酶A存在的情况下，NAC硫酯转化为6'-脱氧查尔酮。
