Stereospecific Organic Reactions in Functionalized Synthetic Bilayer Membranes

1.合成肽脂质的聚集体形态。--肽脂质在水介质中能形成化学和形态稳定的单壁囊泡，通过引入氨基酸残基作为其结构组分而被设计。这些肽脂质具有阳离子，阴离子和非离子头部部分成功地制备，并在水介质中的形态行为进行了检查。特别是，非双层聚集体，立方相和六方相，是第一次与这些合成的脂质构建。单壁囊泡的融合行为。--由非离子和阴离子肽脂质的等摩尔混合物形成的薄壁囊泡通过调节pH或温度通过形成非双层聚集体进行融合。具有离子头部的单壁囊泡在加入具有相反电荷的离子聚合物后瞬间发生融合。维生素依赖酶的功能模型<B_6>。--由肽脂质和疏水性维生素的单壁囊泡形成的全酶模型<B_6>催化氨基酸和酮酸之间的转氨反应，具有周转行为。本实验首次获得了人工合成的转氨酶.维生素&lt;B_（12）&gt;依赖酶的功能模型。--由肽脂质和疏水性维生素&lt;B_（12）&gt;的单壁囊泡形成的全酶模型以用甲基丙二酰-CoA脱氢酶观察到的方式催化碳骨架重排。

1. Aggregate Morphology of Synthetic Peptide Lipids. -- Peptide lipids, which can form chemically and morphologically stable single-walled vesicles in aqueous media, were desinged by incorporation of amino acid residues as their structural components. Those peptide lipids having cationic, anionic, and nonionic head moieties were successfully prepared, and their morphological behavior in aqueous media was examined. In particular, nonbilayer aggregates, cubic and hexagonal phases, were constructed for the first time with these synthetic lipids.2. Fusion Behavior of Single-Walled Vesicles. -- Sintle-walled vesicles formed with equimolar mixtures of nonionic and anionic peptide lipids underwent fusion by adjusting pH or temperature via formation of nonbilayer aggregates. Single-walled vesicles having ionic head moieties underwent fusion instantaneously upon addition of ionic polymers having the opposite charges.3. Functional Model of Vitamin <B_6> -dependent Enzyme. -- A holoenzyme model formed with single-walled vesicles of the peptide lipid and a hydrophobic vitamin <B_6> catalyzed the transamination reaction between an amino acid and a keto acid with turnover behavior. Here, an artificial transaminase was obtained for the first time.4. Functional Model of Vitamin <B_(12)> -dependent Enzyme. -- A holoenzyme model formed with single-walled vesicles of the peptide lipid and a hydrophobic vitamin <B_(12)> catalyzed the carbon-skeletal rearrangement in a manner as observed with methylmalonyl-CoA mutase.