摘要
采用硫酸铵沉淀及色谱分离技术对麦芽根中核酸酶进行了分离纯化 ,通过SephacrylS 2 0 0 ,DEAESephadexA 50andSephacrylS 2 0 0 3步色谱分离 ,得到了部分纯化的两种核酸酶 (Ⅰ和Ⅱ ) ,核酸酶Ⅰ的纯化倍数为 94,核酸酶Ⅱ的纯化倍数为 1 790 .高效液相色谱显示两种酶作用于酵母RNA的产物均为 5′ 核苷酸 .核酸酶Ⅰ的热稳定性比核酸酶Ⅱ好 ,在 55℃下保温 2h后 ,核酸酶I的活力损失仅 1 3% ,而核酸酶Ⅱ则高达 64% .两种酶的最适温度分别为 55℃和 65℃ .两种酶的pH稳定性相似 ,在pH 2 .5～ 9.0范围内很稳定 .核酸酶Ⅰ的最适 pH值为 5.0和 8 0～ 8.5,核酸酶Ⅱ的最适 pH范围为 4.0～ 5.
Two RNases (Ⅰ and Ⅱ) were isolated from extracts of malted barley roots by ammonium sulfate precipitation and purified by chromatography on Sephacryl S 200, DEAE SephadexA 50 and Sephacryl S 200 consecutively. The RNase Ⅰ was purified by 94 fold and RNase Ⅱ 1790 fold. Reaction products of these two RNases with yeast RNA were all 5′ nucleotides determined by HPLC. The heat stability of RNase Ⅰ was better than that of RNase Ⅱ. Activity loss was 64% for RNase Ⅱ and less than 13% for RNase Ⅰ after 2 h at 55 ℃. The optimum temperatures of RNase Ⅰ and RNase Ⅱ were 65 ℃ and 55 ℃ respectively. The pH stability of these two enzymes was similar and they were stable in the pH 2.5～9.0. The optimum pHs were 5.0 and 8.0～8.5 for RNase Ⅰ, and pH 4.0～5.5 for RNase Ⅱ.
出处
《无锡轻工大学学报（食品与生物技术）》
CSCD
北大核心
2001年第3期270-274,共5页
Journal of Wuxi University of Light Industry
