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脂蛋白脂肪酶(LPL)是脂蛋白代谢中的关键酶之一。它分解富含甘油三酯的脂蛋白中的甘油三酯为甘油和脂肪酸。本文利用Heparin-Sepharose-Cl-6B亲合层析法直接分离、提纯了牛奶中的LPL。本方法操作简单,流程较短,分离效果较佳,重复性较好。提纯倍数为7,300,比活为14,000单位/毫克蛋白,回收率为13%左右。经鉴定在SDS-聚丙烯酰胺凝胶电泳中呈现一主要蛋白带,分子量为65,000道尔顿。酶反应的最适底物浓度为4～8毫克,最适pH为8.3～8.5。该酶能被VLDL和HDL激活,LDL和apoA-I无影响。鱼精蛋白和1.0M NaCl有抑制作用。肝素有降低该酶对抑制剂等不利因素的敏感性。牛奶LPL已初步应用于人血清脂蛋白代谢的研究。
Lipoprotein lipase (LPL) is one of the key enzymes in lipoprotein metabolism. It decomposes triglycerides in triglyceride-rich lipoproteins to glycerol and fatty acids. In this paper, Heparin-Sepharose-Cl-6B affinity chromatography direct separation and purification of milk LPL. The method has the advantages of simple operation, short process, better separation effect and better repeatability. Purification factor of 7,300, specific activity of 14,000 units / mg protein, the recovery rate of about 13%. It was identified as a major protein band in SDS-polyacrylamide gel electrophoresis with a molecular weight of 65,000 daltons. The optimum substrate concentration for enzyme reaction was 4 ~ 8 mg and the optimum pH was 8.3 ~ 8.5. The enzyme can be VLDL and HDL activation, LDL and apoA-I no effect. Protamine and 1.0M NaCl have inhibitory effects. Heparin reduces the sensitivity of the enzyme to unfavorable factors such as inhibitors. Milk LPL has been initially applied to the study of human serum lipoprotein metabolism.