Sun W Q, Davidson P
School of Biological Sciences, National University of Singapore, Singapore.
Biochim Biophys Acta. 1998 Sep 16;1425(1):235-44. doi: 10.1016/s0304-4165(98)00076-2.
Trehalose is the most effective carbohydrate in preserving the structure and function of biological systems during dehydration and subsequent storage. We have studied the kinetics of protein inactivation in amorphous glucose/sucrose (1:10, w/w) and glucose/trehalose (1:10, w/w) systems, and examined the relationship between protein preservation, phase separation and crystallization during dry storage. The glucose/trehalose system preserved glucose-6-phosphate dehydrogenase better than did the glucose/sucrose system with the same glass transition temperature (Tg). The Williams-Landel-Ferry kinetic analysis indicated that the superiority of the glucose/trehalose system over the glucose/sucrose system was possibly associated with a low free volume and a low free volume expansion at temperatures above the Tg. Phase separation and crystallization during storage were studied using differential scanning calorimetry, and three separate domains were identified in stored samples (i.e., sugar crystals, glucose-rich and disaccharide-rich amorphous domains). Phase separation and crystallization were significantly retarded in the glucose/trehalose system. Our data suggest that the superior stability of the trehalose system is associated with several properties of the trehalose glass, including low free volume, restricted molecular mobility and the ability to resist phase separation and crystallization during storage.
海藻糖是在脱水及后续储存过程中保存生物系统结构和功能最有效的碳水化合物。我们研究了无定形葡萄糖/蔗糖（1:10，w/w）和葡萄糖/海藻糖（1:10，w/w）体系中蛋白质失活的动力学，并考察了干燥储存过程中蛋白质保存、相分离和结晶之间的关系。在具有相同玻璃化转变温度（Tg）的情况下，葡萄糖/海藻糖体系比葡萄糖/蔗糖体系能更好地保存葡萄糖-6-磷酸脱氢酶。威廉姆斯-兰德尔-费里动力学分析表明，葡萄糖/海藻糖体系相对于葡萄糖/蔗糖体系的优势可能与低于Tg温度时的低自由体积和低自由体积膨胀有关。使用差示扫描量热法研究了储存过程中的相分离和结晶现象，在储存样品中鉴定出三个不同的区域（即糖晶体、富含葡萄糖的无定形区域和富含二糖的无定形区域）。在葡萄糖/海藻糖体系中，相分离和结晶显著延迟。我们的数据表明，海藻糖体系的卓越稳定性与海藻糖玻璃的多种特性有关，包括低自由体积、受限的分子流动性以及在储存过程中抵抗相分离和结晶的能力。
