准噶尔小胸鳖甲抗冻蛋白MPAFP5毕赤酵母表达产物的理化性质

研究准噶尔小胸鳖甲Microdera punctipennis dzhungarica Kasz抗冻蛋白MPAFP5真核表达产物的功能及理化性质。首先用硫酸铵浓度梯度沉淀初步纯化酵母真核表达产物,然后通过细菌低温保护实验检测抗冻蛋白MPAFP5低温保护功能,同时探讨抗冻蛋白MPAFP5在酸碱环境和100℃时的稳定性,并通过等电聚焦凝胶电泳检测其等电点。研究表明MPAFP5真核表达产物在低温下能够提高细菌的存活率,能够耐受高温和一定程度的强酸强碱,其等电点约为5.8左右。准噶尔小胸鳖甲抗冻蛋白MPAFP5真核表达产物与赤翅甲抗冻蛋白(DAFP)的比较表明拟步甲类昆虫抗冻蛋白具有相似的理化性质。

Characterization of antifreeze protein MP AFP5 from Microdera punctipennis dzhungarica expressed in Pichia pastoris

In order to test the function and the physical-chemical properties of the eukaryotic products of antifreeze protein gene mpafp5 cloned from Microdera punctipennis dzhungarica Kasz,the isoelectric point of MPAFP5 was determined by MINI-IEF.The eukaryotic products of MPAFP5 with biological activity can improve the survival rate of the bacterial at low temperature;it was detected by bacterial cryoprotective experiment.In addition,the biological activity of MPAFP5,after treated in acid,alkali and boiled at 100 ℃ respectively,was checked.The results show that MPAFP5 expressed in yeast has biological activity,and its biological activity is stable in pH 1～12,as well as at 100 ℃.Its isoelectric focusing point is about 5.8.The physical-chemical properties of eukaryotic expressing products of antifreeze protein gene mpafp5 are similar to that of Dendroides canadensis antifreeze protein(DAFP).