Tyshenko M G, Doucet D, Davies P L, Walker V K
Department of Biology, Queen's University, Kingston, Ontario, Canada.
Nat Biotechnol. 1997 Sep;15(9):887-90. doi: 10.1038/nbt0997-887.
Antifreeze proteins (AFP) inhibit ice growth by surface adsorption that results in a depression of the freezing point below the melting point. The maximum level of this thermal hysteresis shown by the four structurally unrelated fish AFP is approximately 1.5 degrees C. In contrast, hemolymph and crude extracts from insects can have 5 degrees to 10 degrees C of thermal hysteresis. Based on the isolation, cloning, and expression of a thermal hysteresis protein (THP) from spruce budworm (Choristoneura fumiferana), the vastly greater activity is attributable to a 9 kDa protein. This novel, threonine- and cysteine-rich THP has striking effects on ice crystal morphology, both before and during freezing. It is also 10 to 30 times more active than any known fish AFP, offering the prospect of superior antifreeze properties in cryoprotective applications.
抗冻蛋白（AFP）通过表面吸附抑制冰的生长，这会导致冰点降低至熔点以下。四种结构不相关的鱼类AFP所显示的这种热滞的最大水平约为1.5摄氏度。相比之下，昆虫的血淋巴和粗提取物的热滞可达5至10摄氏度。基于从云杉芽虫（Choristoneura fumiferana）中分离、克隆和表达的一种热滞蛋白（THP），其活性大大提高归因于一种9 kDa的蛋白质。这种富含苏氨酸和半胱氨酸的新型THP在冷冻前和冷冻过程中对冰晶形态都有显著影响。它的活性也比任何已知的鱼类AFP高10至30倍，在冷冻保护应用中具有优异抗冻性能的前景。
