人工分子伴侣介导液相体系中肌球蛋白热稳定性的研究

Artificial Molecular Chaperone-Mediated Thermal Stability of Myosin in the Liquid System

为了进一步提高鱼蛋白的热稳定性，扩大水产蛋白的应用范围，本研究以罗非鱼鱼肉为原料来提取肌球蛋白，并对其进行了热处理，同时以浊度、溶解度、总巯基含量和表面疏水性为指标，试验了十二烷基硫酸钠（SDS）和β-环糊精（β-CD）的添加对肌球蛋白热变性聚集的抑制效果，探讨人工分子伴侣（SDS-β-CD）介导液相体系中肌球蛋白热稳定性的改善．单因素影响的分析表明，在试验范围内，在pH6．0，SDS添加量为5mmol·L-1和蛋白质量浓度2g·L-1的条件下，于50℃热处理30min后添加β-CD（SDS与β-CD的比例为1：2），可以有效抑制肌球蛋白的热变性聚集；热变性抑制机理的分析显示，添加SDS和SDS-β-CD均能有效地抑制热升温处理（升温速率1℃·min-1，30～80℃）对肌球蛋白溶解度和浊度的影响（P≥0．05），抑制热处理对蛋白分子巯基的破坏作用，降低蛋白质分子间的相互作用，由此抑制肌球蛋白热处理过程中的变性聚集，从而改善体系的热稳定性．

In order to further enhance the thermal stability of fish protein, and expand the application range of aquatic protein, in the study, myosin was extracted from tilapia meat, and heat treatment was performed. The turbidity, solubility, total sulphur content, surface hydrophobicity and fluorescence emission spectra of myosin were used as index, and the inhibition effects of the addition of SDS and β-CD on the thermal denaturation and aggregation of myosin were studied, and the improvement of thermal stability of myosin in the liquid system was discussed by artificial molecular chaperone （SDS-β- CD）. Single factor analysis results showed that at pH 6.0, when the concentration of SDS was 5mmol·L-1, the concentration of myosin was 2mg·mL-1 , and when the sample was heated at 50℃ for 30min and β-CD （SDS and β-CD ratio of 1：2） was added, the thermal denaturation and aggregation of myosin were could effectively inhibited. The inhibition mechanism analysis of thermal denaturation and aggregation showed that effects of addition of SDS and SDS-β- CD on the solubility and turbidity （ p 〉0.05） was effectively inhibited during the process of heating treatment （1℃ min-1, 30 -80℃ ）. The destructive effects of heat-treatment on sulfydryl of protein molecules were inhibited, and the interactions between protein molecules were decreased, which resulted in the inhibition of thermal denaturation and aggregation of myosin, and the thermal stability of the system was improved.