Ice growth in supercooled solutions of antifreeze glycoprotein
Ice growth in supercooled solutions of antifreeze glycoprotein
复制标题
抗冻糖蛋白过冷溶液中的冰生长
作者：
K. Harrison;J. Hallett;T. Burcham;R. Feeney;W. Kerr;Y. Yeh
某些蛋白质抑制过冷溶液中冰的生长对许多生物的生存至关重要。有些鱼，既生活在北方零度以下的水域，也生活在南方零度以下的水域，它们的血清中有特殊的蛋白质或糖蛋白，可以抑制冰的形成。尽管这些蛋白质对冰的融化温度只有很小的影响，但在冰晶生长之前，这些鱼的温度可以下降到熔点以下近1k。这种现象被称为冻结滞后，与溶质的正常累加效应相反，它会降低平衡温度，在平衡温度附近，根据符号的不同，微小的变化会导致晶体生长或熔化。有些昆虫还表现出血清冻结迟滞性。我们报道了不同程度的过冷对这些抗冻糖蛋白（AFGPs）溶液中冰晶生长的习惯和速率的影响。我们发现它的结晶速率是纯水的5倍。
Inhibition of ice growth in supercooled solution by certain proteins is vital to the survival of many living organisms. Some fish, native to both subzero northern and southern waters, have special proteins or glycoproteins in their blood serum that inhibit ice formation. Whereas these proteins have only a very small effect on the melting temperature of ice, the temperature of these fish can fall to nearly 1 K below the melting point before ice crystals grow1–3. This phenomenon is called freezing hysteresis, in contrast to the normal colligative effect of solutes that depresses the equilibrium temperature, around which small changes lead to crystal growth or melting depending on sign. Some insects also exhibit a serum freezing hysteresis4. We report the effects of different degrees of supercooling on the habit and rates of growth of ice crystals from solutions of these antifreeze glycoproteins (AFGPs). We find that the crystallization rate is up to five times greater than that in pure water.