Keough D T, de Jersey J, Zerner B
Biochim Biophys Acta. 1985 Jun 10;829(2):164-72. doi: 10.1016/0167-4838(85)90185-2.
The carboxylesterase (carboxylic-ester hydrolase, EC 3.1.1.1) and monoacylglycerol lipase (glycerol-monoester acylhydrolase, EC 3.1.1.23) activities, measured against ethyl butyrate and emulsified monooleoylglycerol respectively, were determined for chicken liver microsomes and highly purified chicken liver carboxylesterase. The activity ratio (ethyl butyrate activity/monooleoylglycerol activity) was approx. 5 for microsomes and approx. 400 for carboxylesterase. Homogenization of microsomes in 0.1 M Tris-HCl buffer (pH 7.92) released all of the ethyl butyrate activity and about half of the monooleoylglycerol activity into a soluble form. Both activities eluted from a Sephadex G-200 column with the same elution volume as that of pure carboxylesterase. This fraction (fraction B) had an activity ratio of approx. 15, an average pI of 5.01 (cf. 4.75 for carboxylesterase), and ran on polyacrylamide gel electrophoresis at pH 8.6 as a number of closely spaced esterase bands with mobilities considerably less than those of the esterase bands present in the carboxylesterase. Fraction B activities against both substrates were completely inhibited by diethyl p-nitrophenyl phosphate and completely precipitated by antibody to carboxylesterase. The remaining half of the monoacylglycerol lipase activity of microsomes was solubilized by treatment with 1.5% (w/v) Triton X-100. This solubilized monoacylglycerol lipase was completely inhibited by diethyl p-nitrophenyl phosphate, showing it to be a serine-dependent enzyme like the carboxylesterases. However, it had no detectable activity against ethyl butyrate, indicating that it is not closely related to the carboxylesterases.
分别以丁酸乙酯和乳化单油酰甘油为底物，测定了鸡肝微粒体和高度纯化的鸡肝羧酸酯酶的羧酸酯酶（羧酸酯水解酶，EC 3.1.1.1）和单酰甘油脂肪酶（甘油单酯酰基水解酶，EC 3.1.1.23）活性。鸡肝微粒体的活性比（丁酸乙酯活性/单油酰甘油活性）约为5，而羧酸酯酶的活性比约为400。在0.1 M Tris-HCl缓冲液（pH 7.92）中对微粒体进行匀浆处理后，所有的丁酸乙酯活性和约一半的单油酰甘油活性以可溶形式释放出来。两种活性从Sephadex G-200柱上洗脱时的洗脱体积与纯羧酸酯酶相同。该组分（组分B）的活性比约为15，平均pI为5.01（相比之下，羧酸酯酶的平均pI为4.75），在pH 8.6的聚丙烯酰胺凝胶电泳中表现为多条紧密排列的酯酶条带，其迁移率明显低于羧酸酯酶中的酯酶条带。组分B对两种底物的活性均被对硝基苯基磷酸二乙酯完全抑制，并被羧酸酯酶抗体完全沉淀。微粒体中剩余的一半单酰甘油脂肪酶活性通过用1.5%（w/v）的 Triton X-100处理而溶解。这种溶解的单酰甘油脂肪酶被对硝基苯基磷酸二乙酯完全抑制，表明它与羧酸酯酶一样是丝氨酸依赖性酶。然而，它对丁酸乙酯没有可检测到的活性，这表明它与羧酸酯酶没有密切关系。
