Recombinant Squalene Synthase. A Mechanism for the Rearrangement of Presqualene Diphosphate to Squalene
作者:Brian S. J. Blagg、Michael B. Jarstfer、Daniel H. Rogers、C. Dale Poulter
DOI:10.1021/ja020411a
日期:2002.7.1
of squalene; and rillingol (ROH), a cyclopropylcarbinyl alcohol formed by addition of water to the tertiary cyclopropylcarbinyl cation previously proposed as an intermediate in the rearrangement of PSPP to SQ (Poulter, C. D. Acc. Chem. Res. 1990, 23, 70-77). The structure and absolute stereochemistry of the tertiary cyclopropylcarbinyl alcohol were established by synthesis using two independent routes
角鲨烯合酶 (SQase) 催化两个分子的法呢基二磷酸 (FPP) 缩合形成二磷酸前角鲨烯 (PSPP),随后 PSPP 重排和 NADPH 依赖性还原为角鲨烯 (SQ)。这些反应是胆固醇生物合成的第一步。当重组 SQase 在二氢 NADPH(NADPH3,一种在烟酰胺环中缺少 5,6-双键的非反应性类似物)存在下与 FPP 一起温育时,形成了三种产物:脱氢角鲨烯 (DSQ),一种八氢番茄红素的 C30 类似物;10(S)-羟基角鲨烯 (HSQ),角鲨烯的羟基类似物;和 rillingol (ROH),一种环丙基甲醇,通过将水添加到叔环丙基甲醇阳离子中形成,先前提出作为 PSPP 重排为 SQ 的中间体 (Poulter, CD Acc. Chem. Res. 1990, 23, 70-77)。叔环丙基甲醇的结构和绝对立体化学是通过使用两条独立的路线合成建立的。从酶催化反应中分离 ROH