源自乳酸克鲁维酵母的β-半乳糖苷酶为胞内酶,其具有乳糖水解能力和半乳糖苷的转移作用.本实验运用单因素试验方法研究乳酸克鲁维酵母乳糖酶的性质.结果表明该酶在pH值为6.0～7.0和37°C～48°C间比较稳定,酶作用最适pH值在6.5,最适反应温度为43℃,Mn2+、Mg2+等对酶有明显的激活作用,而Zn2+、Cu2+等对酶活有抑制作用.该酶以ONPG底物的米氏常数为4.186mmol/L.%β-galactosidase derived from Kluyvemmyces lactis is a cytosolic enzyme, which can hydrolyze lactose into galactose and glucose and transfer galactoside. Properties of lactase isolated from K. Lactis were investigated using single-factor experiment design. The results showed that the optimal pH and temperature of the lactase were 6.5 and at 43℃, respectively. The lactase was found high stability in the range of pH 6.0~7.0 and temperature 37℃-48℃. And the enzyme was significantly activated by the metal ions of Mn2+ and Mg2+. Additionally, the enzyme was inhibited by the metal ions of Zn2+ and Cu2.+ Km value of the lactase was 4.186mmol/L of ONPG.
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