Enzymatic formation of long-chain polyketide pyrones by plant type III polyketide synthases
作者:Ikuro Abe、Tatsuya Watanabe、Hiroshi Noguchi
DOI:10.1016/j.phytochem.2004.08.005
日期:2004.9
synthase (CHS) from Scutellaria baicalensis and stilbene synthase (STS) from Arachis hypogaea accepted CoA esters of long-chain fatty acid (CHS up to the C12 ester, while STS up to the C14 ester) as a starter substrate, and carried out sequential condensations with malonyl-CoA, leading to formation of triketide and tetraketide alpha-pyrones. Interestingly, the C6, C8, and C10 esters were kinetically
黄芩的重组查耳酮合酶 (CHS) 和花生的二苯乙烯合酶 (STS) 接受长链脂肪酸的 CoA 酯(CHS 到 C12 酯,而 STS 到 C14 酯)作为起始底物,并携带与丙二酰辅酶A连续缩合,导致三酮和四酮α-吡喃酮的形成。有趣的是,与生理起始底物相比,C6、C8 和 C10 酯在动力学上更受酶的青睐。kcat/KM 值比对香豆酰辅酶 A 高 1.2 至 1.9 倍。这些酶的催化多样性为 III 型 PKS 反应提供了进一步的机理见解,并表明 CHS 超家族酶参与了植物中长链烷基多酚(如漆酚和银杏酸)的生物合成。