退火温度对第三类鱼抗冻蛋白在冰晶表面吸附结合影响的研究

发布时间：2018-05-31 02:02

本文选题：抗冻蛋白 + 热滞活性　；参考：《内蒙古大学》2016年硕士论文

【摘要】：抗冻蛋白(antifreeze proteins, AFPs)是一类结构多样且具有特殊功能的蛋白质。它能够以非依数性的方式使溶液的冰晶生长点降低,但不影响其熔点,从而使冰晶生长点和熔点之间出现了差值,即为热滞值(Thermal Hysteresis, TH)。因为抗冻蛋白所具有的特殊抗冻效应,使其存在巨大的商业价值,并且在生物工程、制药、医学、食品等方面都有广阔的应用前景。最新实验研究表明,抗冻蛋白在冰晶表面的吸附是一个随着时间不断积累的不可逆过程,并且退火温度不同时,所得到的热滞活性不同,热滞活性会随着退火温度的降低而增大。当退火温度以一定的速率下降时,抗冻蛋白的热滞活性会随着降温速率的增大而减小。以上实验结果表明,抗冻蛋白的热滞活性除了与抗冻蛋白溶液的浓度有关之外,还与抗冻蛋白在冰晶表面吸附结合的时间、退火温度以及降温速率等因素有关。本文基于吸附一抑制理论,根据抗冻蛋白在冰晶表面的吸附动力学过程,建立了抗冻蛋白吸附的二维不可逆动力学模型,并且首次在低过冷度条件下讨论第三类鱼抗冻蛋白的热滞活性的问题中考虑了溶液中的水分子对其吸附的影响。认为在一定过冷温度范围内,水分子会因增加冰晶表面的结合位点而对抗冻蛋白的吸附有一定促进作用。但是温度过低时,水分子将会占据绝对优势而使冰晶不可控制地快速生长。文中根据实验数据拟合得到了退火温度保持在低于熔点下一定数值恒定不变、以及以一定速率下降时水分子和第三类鱼抗冻蛋白之间的竞争关系,根据抗冻蛋白分子结合在冰晶表面所引起表面空位点分布的变化,计算出冰晶表面的覆盖度随时间的变化,进而得出热滞活性随时间变化的关系,并将计算结果与实验数据进行了对比,结果符合较好。
[Abstract]:Antifreeze proteins (AFPs) are a class of proteins with various structures and special functions. It can decrease the growth point of ice crystal without affecting the melting point of the solution in a non-numerical manner, thus the difference between the growth point of ice crystal and the melting point appears, that is, the thermal hysteresis value is thermal hysterics, THN. Because of its special antifreeze effect, antifreeze protein has great commercial value, and has broad application prospects in biological engineering, pharmacy, medicine, food and so on. The latest experimental studies show that the adsorption of antifreeze proteins on the surface of ice crystals is an irreversible process accumulated over time, and the thermal hysteresis activity is different at different annealing temperatures. The thermal hysteresis activity increases with the decrease of annealing temperature. When the annealing temperature decreases at a certain rate, the thermal hysteresis activity of the antifreeze protein decreases with the increase of the cooling rate. The results show that the thermal hysteresis activity of antifreeze proteins is not only related to the concentration of antifreeze protein solution, but also related to the time of adsorption and binding of antifreeze proteins on the ice crystal surface, annealing temperature and cooling rate and so on. Based on the adsorption-inhibition theory, a two-dimensional irreversible kinetic model of antifreeze protein adsorption was established according to the adsorption kinetics of antifreeze protein on the ice crystal surface. The effect of water molecules in solution on the adsorption of the third kind of fish antifreeze proteins was considered for the first time in the study of the thermal hysteresis activity of the third kind of fish antifreeze proteins under the condition of low undercooling. It is concluded that water molecules can promote the adsorption of antifreeze proteins by increasing the binding sites on the ice crystal surface within a certain range of undercooling temperature. But when the temperature is too low, water molecules will dominate and make ice crystals grow uncontrollably fast. According to the experimental data, the competitive relationship between the water molecules and the third kind of fish antifreeze proteins is obtained when the annealing temperature is kept below the melting point and the value is constant, and when the temperature drops at a certain rate. According to the change of the surface vacancy distribution caused by the binding of antifreeze protein molecules on the ice crystal surface, the variation of the surface coverage with time is calculated, and the relationship between the thermal hysteresis activity and the time is obtained. The calculated results are compared with the experimental data and the results are in good agreement.
【学位授予单位】：内蒙古大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：O647.3;O629.73

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