Jain M K, Wu N Y, Morgan T K, Briggs M S, Murray R K
Chem Phys Lipids. 1976 Sep;17(1):71-8. doi: 10.1016/0009-3084(76)90037-2.
The influence of thirty-four adamantane, protoadamantane, and homoadamantane derivatives on the phase transition characteristics of the bilayer in dipalmitoyl lecithin liposomes has been determined by differential scanning calorimetry. Each of these compounds induces a broadening of the phase transition profile of the lipid bilayer that is dependent upon the concentration of the solute and its molecular structure. The concentration--response curves obtained for these solutes suggest that the cage compound derivatives modify the phase properties and under some conditions may induce a phase separation in the doped bilayer. The relative activity sequences obtained for the compounds examined cannot be accounted for by simple considerations of lipid/water partition coefficients, substitution constants based on free energy relationships, or the relative polarities or sizes of substituent groups. The observations are consistent with the hypothesis that the position and orientation of a solute within the bilayer are critical factors in determining its relative potency. The position of a solute within the bilayer is significantly controlled by the presence of polar substituents and by the relative geometric relationships of these groups. For a given substituent group, the shape and size of the hydrocarbon cage becomes increasingly important. It is apparent that seemingly minor modifications in the structure of a solute can significantly alter its influence on the phase transition behavior of a bilayer.
通过差示扫描量热法测定了34种金刚烷、原金刚烷和高金刚烷衍生物对二棕榈酰卵磷脂脂质体双层膜相变特性的影响。这些化合物中的每一种都会导致脂质双层膜相变曲线变宽，这取决于溶质的浓度及其分子结构。这些溶质的浓度-响应曲线表明，笼状化合物衍生物会改变相性质，在某些条件下可能会在掺杂的双层膜中诱导相分离。所研究化合物的相对活性序列不能通过简单考虑脂质/水分配系数、基于自由能关系的取代常数或取代基团的相对极性或大小来解释。这些观察结果与以下假设一致，即溶质在双层膜中的位置和取向是决定其相对效力的关键因素。溶质在双层膜中的位置受极性取代基的存在以及这些基团的相对几何关系的显著控制。对于给定的取代基团，烃笼的形状和大小变得越来越重要。显然，溶质结构看似微小的改变会显著改变其对双层膜相变行为的影响。
