Burton B K, Mueller H W
Biochim Biophys Acta. 1980 Jun 23;618(3):449-60. doi: 10.1016/0005-2760(80)90263-5.
Two peaks of lysosomal acid lipase activity were purified from normal human placenta. Acid lipase I, with an estimated molecular weight of 102 500, was purified 1016-fold while acid lipase II, with an estimated molecular weight of 30 600, was purified 3031-fold. The final yields of enzyme activity for acid lipase I and II were 0.9% and 2.2% respectively. The purity of the final preparations was documented by demonstration of a single protein band on polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. Both preparations of the purified enzyme demonstrated activity towards triolein, cholesteryl oleate and the artificial substrate 4-methylumbelliferyl oleate. Examination of Km values, thermal stability, pH optima, and electrophoretic mobility revealed similar properties for the two enzyme peaks. The response of the two enzyme preparations to inhibitors was similar with both being significantly inhibited by 0.2 M NaCl, 0.2 M KCl, 5 mM HgCl2 and 5 mM p-chloromercuribenzoate. The activity of the two preparations as assayed with either triolein or cholesterol oleate was not significantly affected by the addition of bovine serum albumin. In contrast, the 4-methylumbelliferyl oleate activity of both preparations was significantly inhibitred by albumin. These findings support the hypothesis that the same enzyme or enzymes are responsible for the intralysosomal hydrolysis of triacylglycerols and cholesterol esters in human tissues.
从正常人胎盘中纯化出了溶酶体酸性脂肪酶活性的两个峰。酸性脂肪酶I的估计分子量为102500，纯化了1016倍；而酸性脂肪酶II的估计分子量为30600，纯化了3031倍。酸性脂肪酶I和II的酶活性最终产率分别为0.9%和2.2%。在十二烷基硫酸钠存在下，通过聚丙烯酰胺凝胶电泳显示单一蛋白条带，证明了最终制剂的纯度。两种纯化酶制剂对三油精、胆固醇油酸酯和人工底物4-甲基伞形酮油酸酯均表现出活性。对米氏常数、热稳定性、最适pH值和电泳迁移率的检测表明，这两个酶峰具有相似的性质。两种酶制剂对抑制剂的反应相似，二者均被0.2M氯化钠、0.2M氯化钾、5mM氯化汞和5mM对氯汞苯甲酸显著抑制。用三油精或胆固醇油酸酯测定时，添加牛血清白蛋白对两种制剂的活性没有显著影响。相反，白蛋白显著抑制了两种制剂的4-甲基伞形酮油酸酯活性。这些发现支持了这样一种假说，即相同的一种或多种酶负责人体组织中三酰甘油和胆固醇酯的溶酶体内水解。
