Katsikas H, Quinn P J
Biochim Biophys Acta. 1982 Jul 28;689(2):363-9. doi: 10.1016/0005-2736(82)90270-x.
The interaction between ubiquinone homologues with polyisoprenoid chain lengths varying from 3 to 10 units and dipalmitoylphosphatidylcholine bilayers has been examined by differential scanning calorimetry and wide angle X-ray diffraction analysis. Decreasing the polyisoprenoid chain lengths of ubiquinone in mixed dispersions with phospholipid in mol ratios of about 10 mol% caused a decrease in the gel-liquid crystalline phase transition temperature of the phospholipid and a broadening of the transition. Enthalpy measurements showed that most of the phospholipid (greater than 92%) was involved in the transition endotherm and the formation of a gel phase was also confirmed by the presence of a sharp X-ray reflection of 0.42 nm. These results are consistent with a model in which all of the ubiquinone homologous ultimately undergo a phase separation from phospholipid molecules entering a gel phase on cooling below the phase transition temperature. Reducing the length of the polyisoprenoid chain alters the amphipathic balance of the ubiquinone molecules and is reflected in the tendency of shorter chain ubiquinones to intercalate between the phospholipid molecules upon reheating through the main phase transition.
通过差示扫描量热法和广角X射线衍射分析，研究了聚异戊二烯链长度在3至10个单元之间变化的泛醌同系物与二棕榈酰磷脂酰胆碱双层之间的相互作用。在与磷脂的摩尔比约为10 mol%的混合分散体中，降低泛醌的聚异戊二烯链长度会导致磷脂的凝胶-液晶相转变温度降低以及转变变宽。焓测量表明，大部分磷脂（大于92%）参与了转变吸热过程，并且0.42 nm的尖锐X射线反射的存在也证实了凝胶相的形成。这些结果与一个模型一致，在该模型中，所有泛醌同系物最终都会与在冷却至低于相转变温度时进入凝胶相的磷脂分子发生相分离。缩短聚异戊二烯链的长度会改变泛醌分子的两亲平衡，这反映在较短链泛醌在通过主相转变重新加热时插入磷脂分子之间的趋势上。
