沙冬青抗冻蛋白热滞活性的DSC研究

在某些极地鱼类的血清以及某些昆虫和植物中 ,人们发现了一类特殊的物质 .它们的共同特点是能通过直接与冰晶核相互作用，抑制冰晶核的形成和生长，从而降低溶液冰点 .现已发现的这类抗冻物质都属于蛋白质，被统称为抗冻蛋白（ Antifreeze Proteins, AFPs） .抗冻蛋白能以非依数性形式大大降低溶液的冰点，但对熔点的影响很微弱，而且遵从依数性的原则，使冰点低于平衡态的熔点，溶液处于反常的非平衡相变状态 .这种冰点低于熔点的特性称为热滞 (Hysteresis).因此，抗冻蛋白也叫热滞蛋白或温度迟滞蛋白（ Thermal Hysteresis Proteins, …

DSC Study on the Thermal Hysteresis Activity of Plant Antifreeze Proteins

Differential scanning calorimetry （DSC） was used to measure thethermal hysteresis activity(THA) of plant antifreeze proteins(AFPs). The results reveal that DSC is a good method to screen and study AFPs. In the sixteen components extracted from Ammopipanthus mongolicus leaves, one(P3S1) was found to have apparent thermal hysteresis activity by DSC. As the amount of ice nuclei in the sample decreased, the THA of P3S1 increased from 0.01 ℃ to 0.65 ℃ . It is notable that the two-peak thermal hysteresis effect was observed. Two endothermic peaks appeared in the melting process of P3S1, while the freezing peak also consisted of two peaks. The peaks appeared antecedently showed larger thermal effect. This phenomenon shows P3S1 has two different kinds of interaction with water and ice crystal. It is probably an important property of a class of AFPs.