不同质量浓度鲢鱼肌球蛋白低温自组装动力学及理化性质

Self-Assembly Kinetics and Physicochemical Properties of Silver Carp Myosin under Conditions with Different Concentrations and Low Temperature

以鲢鱼肌球蛋白为研究对象,通过粒径分布、激光共聚焦图像和浊度等指标比较不同质量浓度的肌球蛋白在低温下自组装动力学及理化性质,为提高其凝胶性能提供参考。结果表明:肌球蛋白在低温放置过程中会发生自组装,使浊度和粒径随放置时间延长及蛋白质量浓度增加而整体呈增大趋势;其自组装过程可分为成核、组装、平衡3个阶段;质量浓度较低时(0.1～0.3 mg/mL),自组装12 h即趋于平衡,当蛋白质量浓度大于等于0.5 mg/mL时,则需较长时间才能达到组装平衡。模型lgZ/270.0=(0.018 2ρ+0.006 79)t/2.303(ρ表示蛋白质量浓度/(mg/mL);t表示组装时间/h;Z表示t时刻平均粒径/nm)可以很好地描述不同质量浓度肌球蛋白在低温自组装过程中粒径随放置时间的变化,提高质量浓度可促进分子间的相互作用,组装速率和尺寸也随之增大,当蛋白质量浓度高于0.5 mg/mL时,形成了激光共聚焦显微镜可观察到的组装体,肌球蛋白快速自组装的临界质量浓度是0.5 mg/mL。

In the present study, the self-assembly kinetics and physicochemical properties of silver carp myosin were investigated at low temperature (4℃) through particle size distribution, confocal laser scanning microscopy (CLSM) images and turbidity. Myosin could be assembled at 4℃. The turbidity and particle size increased with prolonging assembly time and increasing myosin concentration. Myosin self-assembling could be divided into three stages: nucleating, assembly, and balance. For the samples at low concentrations (0.1-0.3 mg/mL), myosin assembly tended to the balance at 12 h. It took more time for myosin under the condition with the concentration higher than 0.5 mg/mL to reach the assembly balance. In addition, the particle size of myosin assembles fit the model ‘lgZ/270.0=(0.0182ρ+0.00679)t/2.303' very well. Increasing myosin concentration could promote protein interaction, thus leading to the increase in the assembling rate and particle size. The assemblies could be observed by CLSM under the condition with the concentration higher than 0.5 mg/mL. The critical concentration of myosin was 0.5 mg/mL for rapid self-assembly