猪脑乙酰胆碱酯酶的分离纯化和性质研究

通过离心、硫酸铵分级沉淀、DEAE-Sepharose和Superdex-200层析等步骤，从猪脑中获得电泳纯乙酰胆碱酯酶，该酶比活力和纯化倍数分别为2.05 U/mg和26.97，酶活回收率为11.95%；该酶分子质量为257.30 kD，亚基为66.94 kD；以碘化硫代乙酰胆碱为底物时，酶的最适反应温度为37 ℃，最适pH值为7.4，且在40 ℃以下，pH 6.0～8.0有较好的稳定性；最适底物浓度为4.0 mmol/L，Km为0.94 mmol/L。Ba2+和Zn2+对该酶有强烈的抑制作用，而低浓度Mg2+对该酶有激活作用。

Purification and Characterization of Acetylcholinesterase from Porcine Brain

Acetylcholinesterase (AChE) was purified from porcine brain by consecutive steps including centrifugation,ammonium sulfate fractionation, DEAE-Sepharose chromatography and Superdex-200 gel filtration chromatography. Thepurified AChE exhibited a specific activity of 2.05 U/mg, with 26.97-fold purification and an activity yield of 11.95%. Therelative molecular weight of AChE was 257.30 kD, and the subunit molecular weight was 66.94 kD. The optimal pH andtemperature for the enzyme were 7.4 and 37 ℃, respectively. The enzyme was stable below 40 ℃ and in the pH range of6.0–8.0. At an optimal substrate concentration of 4.0 mmol/L, the apparent Km was 0.94 mmol/L. The activity of AChE wasinhibited by Ba2+ or Zn2+ , but enhanced by Mg2+.