【摘要】 通过平板初筛和摇瓶复筛,得到一株胆固醇酯酶的高产菌株,研究了pH值、温度、底物浓度、一些有机和无机试剂对胆固醇酯酶酶促反应速度的影响。研究发现,胆固醇酯酶有较好的酸碱稳定性,pH值为5.0￣8.0;最适pH值和最适温度分别为pH7.0和40℃,该酶的动力学研究表明,对胆固醇亚油酸酯和胆固醇油酸酯都表现为典型的米氏规律,Km值分别为2.2×10-5mol/L3.1×10-5mol/L,同时研究了一些金属离子和有机化合物对酶活性的影响,发现Mg2+、EDTA对胆固醇酯酶有激活作用。更多还原

【Abstract】 A high-yield cholesterol esterase-producing strain of Rhodococcus sp. was obtained with plate method and shake flask fermentation. The effects of pH, temperature, substrate concentration and organic/inorganic reagents on the velocity of cholesterol esterase(COE) were inve-stigated. The enzyme was stable over a broad range of pH 5.0-8.0. The optimum pH and temperature were 7.0 and 40℃, respectively. The behavior of cholesterol esterase was in accord with Michaelis-Menten kinetics when cholesterol linoleate or cholesterol oleate was used as substrate, with a Km of 2.2×10-5mol/L or 3.1×10-5mol/L, respectively. The effects of metal ions and organic compounds on enzyme activity were also studied. It was found that Mg2+ and EDTA could activate the cholesterol esterase.更多还原