人血清小分子蛋白质分离中等电点沉淀法的探索

Investigation of isoelectric precipitation method in process of separating low-molecular-weight protein from human serum

目的：探索经等电点沉淀法去除高丰度蛋白后用聚丙烯酰胺凝胶电泳分离血清中小分子量（〈10kD）蛋白质的方法。方法：血清经U9处理后加不同pH值的缓冲液沉淀高丰度大分子量蛋白，取上清超滤（MW=3kD）浓缩、置换，用Tricine—SDS—PAGE电泳检测。结果：血清经pH5．6的醋酸钠缓冲液处理后，可提高低丰度蛋白上样量6～8倍，电泳图可显示更多小分子蛋白条带。结论：等电点沉淀法可以有效沉淀人血清中高丰度大分子量蛋白，是一种分离血清部分小分子量蛋白质简便、经济、有效的前期处理方法。

Objective：To separate low - molecular - weight protein （ 〈 10 kD） in human serum with Tricine - SDS - PAGE system after the high -abundance proteins were depleted by isoelectric precipitation method. Methods：Human serum was treated with U9 and then different pH buffer solutions were added to precipitate highabundance proteins respectively. The supernate fluid was concentrated, desalted and exchanged buffer by ultra filtration（3kD） and the trapped fluid was analysised on Tricine -SDS - PAGE. Results：Depletion of high - abundance proteins with pH 5.6 acetate sodium buffer can enhance the remaining proteins load on the one - dimensional ectrophoresis 6 - 8 times and more low - molecular - weight protein stripes were detected on the Tricine- SDS- PAGE gel. Conclusion： The isoelectric precipitation method can remove high -abundance, high- molecular-weight proteins effectively. On the contray, most low - molecular - weight proteins were seldom deleted. It is an convenient, eco- nomic, effective prefractionation method of resolving micro molecular protein （ 〈 10 kD） in human serum.