Bruzik K S, Hakeem A A, Tsai M D
Department of Medicinal Chemistry and Pharmacognosy (m/c 781), College of Pharmacy, University of Illinois at Chicago 60612.
Biochemistry. 1994 Jul 12;33(27):8367-74. doi: 10.1021/bi00193a026.
Derivatives of chiro-inositol have been recently shown to mediate many important biological processes. This work addresses the question of whether phosphatidylinositol-specific phospholipase C (PI-PLC) could be involved in the generation of these chiro-inositol derivatives. Two diastereomers of the analog of phosphatidylinositol containing 1D- and 1L-chiro-inositol have been synthesized. 1D-2-O-(1,2-O-Dipalmitoyl-sn-glycero-3-phospho)-chiro-inositol (1D-chiro-PI) was synthesized in 12 steps starting from 1D-2,3,4,5-O-tetrakis(methoxymethylene)-myo-inositol by the inversion of the hydroxyl group at the 1-position of inositol followed by several protection/deprotection and phosphorylation steps. IL-2-O-(1,2-O-Dipalmitoyl-sn-glycero-3-phospho)-chiro-inositol (1L-chiro-PI) was synthesized in eight steps starting from 1L-chiro-inositol using regioselective silylation of the hydroxyl group at the 2-position of chiro-inositol in a key synthetic stage. Both diastereomers were subjected to cleavage by PI-PLC from Bacillus thuringiensis. The reaction of 1L-chiro-PI produced chiro-inositol 1,2-cyclic phosphate, however, at the rate of 10(-3) of that attained with the natural substrate, phosphatidylinositol. On the other hand, 1D-chiro-PI was found to be resistant to PI-PLC. These results suggest that the natural chiro-inositol derivatives should have the 1L-configuration if they are produced by PI-PLC, which is in contrast to the 1D-configuration reported by others. We therefore have isolated chiro-inositol from the total bovine liver lipid and determined its absolute configuration. The obtained chiro-inositol was found to be exclusively of the 1L-configuration, with the enantiomeric purity exceeding 99%.
手性肌醇衍生物最近被证明可介导许多重要的生物学过程。这项工作探讨了磷脂酰肌醇特异性磷脂酶C（PI-PLC）是否可能参与这些手性肌醇衍生物的生成。已合成了含有1D-和1L-手性肌醇的磷脂酰肌醇类似物的两种非对映异构体。1D-2-O-(1,2-O-二棕榈酰-sn-甘油-3-磷酸)-手性肌醇（1D-手性-PI）从1D-2,3,4,5-O-四(甲氧基亚甲基)-肌醇开始，经过12步合成，通过肌醇1位羟基的构型翻转，随后进行几步保护/脱保护和磷酸化步骤。1L-2-O-(1,2-O-二棕榈酰-sn-甘油-3-磷酸)-手性肌醇（1L-手性-PI）从1L-手性肌醇开始，经过八步合成，在关键合成阶段对手性肌醇2位的羟基进行区域选择性硅烷化。两种非对映异构体都用苏云金芽孢杆菌的PI-PLC进行裂解反应。1L-手性-PI的反应生成了手性肌醇1,2-环磷酸酯，然而，其反应速率仅为天然底物磷脂酰肌醇反应速率的10^(-3)。另一方面，发现1D-手性-PI对PI-PLC具有抗性。这些结果表明，如果天然手性肌醇衍生物是由PI-PLC产生的，它们应该具有1L-构型，这与其他人报道的1D-构型相反。因此，我们从牛肝总脂质中分离出手性肌醇并确定了其绝对构型。所得到的手性肌醇被发现完全是1L-构型，对映体纯度超过99%。
