细菌Bacillus sp.2粗酶液通过(NH4)2SO4分级分离、Q Sepharose FF、Sephadex G-100(Ⅰ)、Hydroxyapatite和Sephadex G-100(Ⅱ)柱层析分离,纯化了一种以NADPH为辅酶的3-脱氧葡糖醛酮(3-DG)代谢酶,定性为2-羰基醛还原酶.纯化酶的比活力为63.75 U/mg,在SDS-聚丙烯酰胺凝胶上显示一条蛋白质带.该酶分子质量约为32 ku,酶反应最适pH约为6.2, 在pH 5~8, 温度25~30℃之间酶保持稳定;该酶对3-DG的Km为2.3 mmol/L.添加适量的EDTA、巯基乙醇或二硫苏糖醇能明显提高酶的活性;而碘乙酸、N-乙基顺丁烯二酰亚胺抑制酶的活性.
A NADPH-dependent 3-DG metabolizing enzyme was isolated and purified to electrophoretic homogeneity from Bacillus sp.2 by combined consecutive treatment consisting of ammonium sulfate fractionation, Q Sepharose FF, Sephadex G-100(Ⅰ), Hydroxyapatite and Sephadex G-100(Ⅱ) column chromatographies. The specific activity of purified 3-DG metabolizing enzyme was 63.75 U/mg. The molecular weight of the enzyme was about 32 ku. 2-Oxoaldehyde compounds were found to be specifically good substrate for this reductase. The optimum pH of the enzyme activity was 6.2. The enzyme was stable in the pH range from 5 to 8 and in the temperature range from 25℃ to 30℃. The Km for 3-DG was 2.3 mmol/L. Suitable amount of EDTA、β-mercaptoethanol and dithiothreitol enhanced the enzyme activity, but the activity of the enzyme was partially lost by adding iodoacetic acid or N-ethylmaleimide.
梁智群,粟桂娇,李湘萍,莫柏立,梁静娟.细菌3-脱氧葡糖醛酮代谢酶的纯化及性质研究[J].生物化学与生物物理进展,2000,27(2):192-196
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