Crowe J H, Whittam M A, Chapman D, Crowe L M
Biochim Biophys Acta. 1984 Jan 11;769(1):151-9. doi: 10.1016/0005-2736(84)90018-x.
Surface pressure studies of phospholipid monomolecular films of dimyristoylphosphatidylcholine (DMPC) and dipalmitoylphosphatidylcholine (DPPC) formed at an air/water interface have been made and the effects on the films studied when various carbohydrates are present in the subphase. The results obtained show that at a given temperature, the area per molecule of DPPC increases with increasing concentration of the carbohydrate in the subphase. The carbohydrate which has the greatest expanding effect on the phospholipid monolayer is glycerol, followed in turn by trehalose, sucrose, glucose, raffinose, and inositol. The mechanism of monolayer expansion by glycerol is different from that observed in other carbohydrates, as the following experiments demonstrate. Below the phase transition temperature of DPPC, the area per molecule of DPPC at a pressure of 12.5 dyn/cm is the same with and without glycerol in the subphase. However, when the monolayer is heated to a temperature above the phase transition temperature for DPPC, the area/molecule on glycerol is considerably greater than the area/molecule on water at the same surface pressure. Cooling the monolayer back to the lower temperature produces an area/molecule of DPPC which is identical on both water and glycerol subphases. Glycerol therefore has no effect on the low-temperature (condensed) monolayers but causes expansion of the high-temperature (expanded) monolayers. By contrast with glycerol, both trehalose and sucrose interact with the DPPC monolayer producing an increased area/molecule over that observed on water, both with low-temperature (condensed) monolayers and with the high-temperature (expanded) monolayers. The efficiency of these carbohydrates at expanding the monolayer films (with the exception of glycerol) shows a strong correlation with their ability to stabilize membrane structure and function at low water contents.
已对在空气/水界面形成的二肉豆蔻酰磷脂酰胆碱（DMPC）和二棕榈酰磷脂酰胆碱（DPPC）的磷脂单分子膜进行了表面压力研究，并研究了当亚相中存在各种碳水化合物时对这些膜的影响。所得结果表明，在给定温度下，DPPC的每分子面积随亚相中碳水化合物浓度的增加而增大。对磷脂单层具有最大扩张作用的碳水化合物是甘油，其次依次是海藻糖、蔗糖、葡萄糖、棉子糖和肌醇。如下列实验所示，甘油使单层扩张的机制与其他碳水化合物中观察到的不同。在DPPC的相变温度以下，在12.5达因/厘米的压力下，亚相中有无甘油时DPPC的每分子面积相同。然而，当单层加热到高于DPPC相变温度的温度时，在相同表面压力下，甘油上的每分子面积远大于水上的每分子面积。将单层冷却回较低温度时，DPPC的每分子面积在水和甘油亚相上是相同的。因此，甘油对低温（凝聚态）单层没有影响，但会导致高温（膨胀态）单层的扩张。与甘油相反，海藻糖和蔗糖都与DPPC单层相互作用，导致每分子面积比在水上观察到的增加，无论是低温（凝聚态）单层还是高温（膨胀态）单层。这些碳水化合物（除甘油外）在扩张单层膜方面的效率与其在低含水量下稳定膜结构和功能的能力密切相关。
