【摘要】 目的:研究一组新型蚯蚓脱氧核糖核酸酶(earthworm desoxyribonucleases,EWDs)的主要生化性质。方法:采用SDS-PAGE、MALDI-TOF、紫外分光光度方法。结果:确定了EWD1,EWD2、EWD3(总称为:EWDs)的分子量分别为157.2kDa,69.1kDa和63.5kDa。37℃,pH4.6以小牛胸腺DNA为底物时,EWDs的Km值分别为1.58mg/ml,3.95mg/ml,1.52mg/ml;Vmax分别为5.36mg/(ml·min),2.87mg/(ml·min),4.89mg/(ml·min)。EWDs在55℃保温10min,酶活性完全丧失,在40℃以下酶活性都比较稳定。这3种脱氧核糖核酸酶最适pH值分别是5.2,4.4,4.8,酸性条件下较稳定。Mn2+,Ca2+是蚯蚓组织脱氧核糖核酸酶EWD1,EWD2,EWD3的抑制剂,Mg2+对EWD3有较明显的抑制作用。结论:蚯蚓组织中发现的脱氧核糖核酸酶EWDs具有独特的酶学特征,不同于已经发现的DNaseⅠ和DNaseⅡ,是种新型的脱氧核糖核酸酶,但其作用机理和分类有待于进一步的研究和归类。更多还原

【Abstract】 Objective:To study the main characteristics of earthworm deoxyribonucleases(EWDs). Methods: SDS-PAGE and MADLT-TOF were used to the study. Results: The molecular weights of EWDs (EWD1, EWD2 and EWD3) were 157.2kDa,69.1kDa and 63.5kDa respectively. Under the condition of 37℃,pH4.6 and take calf thymus DNA as substrate,the Km values of EWDs were 1.58mg/ml, 3.95mg/ml,1.52mg/ml and the Vmax were 5.36mg/(ml·min),2.87mg/(ml·min)and 4.89mg/(ml·min), respectively. The EWDs were sensitive to temperature, which didn’t show any activity when the temperature rises to 55℃ for 10 min and showed stability below 40℃. The optimum pH were 5.2,4.4,4.8,respectively. Mn2+,Ca2+ were inhibitors of EWDs, and Mg2+ had negative effect on EWD3 enzyme activity. Conclusion: EWDs has unique characteristics which are different from DNases known before.更多还原