[关键词]
[摘要]
本文以橡胶籽蛋白溶液为原料,分离得到提取β-葡萄糖苷酶,研究了不同浓度的变性剂对β-葡萄糖苷酶酶活的影响,并通用激光粒径分析和分子荧光光谱分析等方法研究了变性剂对酶的空间结构的影响。结果表明:β-葡萄糖苷酶的酶活随变性剂浓度的增加大体上呈现下降趋势,温度的增加会加速下降的速度,通过对β-葡萄糖苷酶的空间结构分析发现尿素变性酶后,酶溶液的分子粒径变小,推断为β-葡萄糖苷酶的多聚体结构发生解聚。低浓度尿素在1 h时间内对β-葡萄糖苷酶有激活作用,酶活力明显提高,表明酶的空间结构变化与尿素浓度大小有关。通过分子荧光光谱分析发现随酶溶液中尿素浓度增加,荧光峰位红移,表明色氨酸残基不断暴露,蛋白质分子结构不断展开。本研究为进一步开发利用橡胶籽中β-葡萄糖苷酶提供了实验依据。
[Key word]
[Abstract]
β-Glucosidase extract was separated from a rubber seed protein solution to study the effect of different concentrations of denaturants on β-glucosidase activity, and laser particle size analysis and molecular fluorescence spectroscopy were used to study the effect of denaturants on the spatial structure of β-glucosidase. β-Glucosidase activity showed a declining trend with increased denaturant concentration, and increased temperature accelerated the pace of this decline. Analysis of the spatial structure of β-glucosidase showed that the molecular particle size in the enzyme solution decreased after the enzyme was denatured by urea, implying that the polymeric structure of β-glucosidase was depolymerized. β-Glucosidase could be activated at a low urea concentration within one hour, and enzyme activity improved significantly, which shows that the spatial structure changes of the enzyme were related to urea concentration. Analysis of fluorescence spectra showed that the location of the fluorescence peak moved with increased urea concentration in the enzyme solution, indicating that tryptophan residues were continuously exposed and the protein structure was continuously opened.
[中图分类号]
[基金项目]
国家自然科学基金项目(31460407);海南大学青年基金项目(qnjjl228)