Adamson E D, Ayers S E, Deussen Z A, Graham C F
Biochem J. 1975 May;147(2):205-14. doi: 10.1042/bj1470205.
The solubilization of 80% of the acetylcholinesterase activity of mouse brain was performed by repeated 2h incubations of homogenates at 37 degrees C in an aqueous medium. Analysis of the soluble extract by gel filtration on Sephadex G-200 showed that up to 80% of the enzyme activity was eluted in a peak which was estimated to consist of molecules of about 74000mol.wt. This peak was called the monomer form of the enzyme. After 3 days at 4 degrees C, the soluble extract was re-analysed and was eluted from the column in four peaks of about 74000, 155000, 360000 and 720000 mol.wt. Since the total activity of the enzyme in these peaks was the same as that in the predominantly monomer elution profile of fresh enzyme, we concluded that the monomer had aggregated, possibly into dimers, tetramers and octomers. Extracts of the enzyme were analysed by polyacrylamide-gel electrophoresis and the resulting multiple bands of enzyme activity on gels were shown to separate according to their molecular sizes, that is by molecular sieving. All these forms had similar susceptibilities to the inhibitors eserine, tetra-isopropyl pyrophosphoramide and compound BW 284c51 [1,5-bis-(4-allyldimethylammoniumphenyl)pentan-3-one dibromide]. Thus the forms of the enzyme in mouse brain which can be detected by gel filtration and polyacrylamide-gel electrophoresis may all be related to a single low-molecular-weight form which aggregates during storage. This supports similar suggestions made for the enzyme in other locations.
通过在水性介质中于37℃对匀浆进行重复2小时的孵育，实现了对小鼠脑80%乙酰胆碱酯酶活性的增溶。通过在Sephadex G - 200上进行凝胶过滤对可溶性提取物进行分析，结果表明高达80%的酶活性在一个峰中被洗脱出来，据估计该峰由分子量约为74000的分子组成。这个峰被称为酶的单体形式。在4℃放置3天后，对可溶性提取物再次进行分析，其从柱上洗脱时出现了四个峰，分子量分别约为74000、155000、360000和720000。由于这些峰中酶的总活性与新鲜酶主要为单体的洗脱图谱中的活性相同，我们得出结论，单体已经聚集，可能形成了二聚体、四聚体和八聚体。通过聚丙烯酰胺凝胶电泳对酶提取物进行分析，结果表明凝胶上产生的多条酶活性带根据其分子大小进行分离，也就是通过分子筛作用分离。所有这些形式对抑制剂毒扁豆碱、四异丙基焦磷酰胺和化合物BW 284c51 [1,5 - 双 - (4 - 烯丙基二甲基铵苯基)戊烷 - 3 - 酮二溴化物]具有相似的敏感性。因此，通过凝胶过滤和聚丙烯酰胺凝胶电泳能够检测到的小鼠脑中酶的形式可能都与一种单一的低分子量形式有关，该形式在储存过程中会聚集。这支持了针对其他部位该酶所提出的类似观点。
