丝素蛋白的抗冻活性探析

An Analytical Study of the Antifreeze Activity of Silk Fibroin

为制备可量产、成本低且高效的低温保护剂,研究一种源于家蚕茧的丝素蛋白的抗冻活性。借鉴抗冻蛋白的研究方法,先制备实验溶液,再通过质谱分析和色谱测定来分析丝素蛋白的分子量、氨基酸组成以及二级结构,通过冰晶重结晶抑制实验分析丝素蛋白溶液的抗冻活性。结合丝素蛋白的氨基酸组成与结构等信息分析丝素蛋白作为低温保护剂的保护机制。研究结果表明,丝素蛋白中的β-折叠结构有助于丝素蛋白与冰晶充分结合,丝素蛋白分子吸附于冰的生长表面,侧链上的β-折叠结构与冰晶结合,还可以通过分子间的疏水作用吸附到冰晶表面,通过覆盖和屏蔽作用抑制冰晶生长。这种抗冻活性随着丝素蛋白溶液质量浓度的增加而增强。

To prepare a mass-producible,low-cost and highly efficient cryoprotectants,this paper carried out research on the antifreeze activity of silk fibroin derived from silkworm cocoons in the method that is used to study antifreeze protein.After the solutions of silk fibroin were prepared,the molecular weight of silk fibroin was determined,and the composition and the secondary structure of its amino acid were analyzed by means of mass spectrometry and chromatography,based on which the protective mechanism of silk fibroin as cryoprotectants was discussed.The antifreeze activity of the solutions was finally tested through the experiment on the inhibition of ice recrystallisation.The results have shown that theβ-sheets in silk fibroin contribute to the full combination of silk fibroin with ice crystals.The silk fibroin molecules are absorbed onto the surface of ice,in which theβ-sheets on the side chain are combined with ice crystals or even be adsorbed onto its surface,effectively inhibiting the growth of ice crystals by covering and screening.The thicker the concentration of the solutions are,the stronger the antifreeze activity becomes.