Clark S B, Laboda H L
Department of Biophysics, Boston University School of Medicine, Housman Medical Research Center, MA 02118-2394.
Lipids. 1991 Jan;26(1):68-73. doi: 10.1007/BF02544027.
Lipolysis of emulsified glycerol tri[9,10-3H]oleate by lipoprotein lipase purified from bovine milk (E.C.3.1.1.34) and by hepatic lipase purified from rat liver perfusate was studied as a function of the phosphatidylcholine molecular species and the cholesterol content of the emulsions. Overall, the activities of the two enzymes were similar on a molar basis. Lipoprotein lipase initial lipolysis rates also were comparable for emulsions made with egg phosphatidylcholine or with saturated (dimyristoyl, dipalmitoyl and distearoyl) phosphatidylcholines when cholesterol was low. Increasing the cholesterol content of the emulsion from 2-3 mole percent to 7-14 mole percent reduced triolein lipolysis by lipoprotein lipase in emulsions made with saturated phosphatidylcholines. Rat hepatic lipase was more sensitive to increased cholesterol in emulsions made with saturated phosphatidylcholines than was lipoprotein lipase. The ability to maintain triolein lipolysis during longer incubations differed strikingly among the emulsions and for the two enzymes. Lymph chylomicrons were better substrates for both enzymes than any of the emulsions.
研究了从牛乳中纯化的脂蛋白脂肪酶（E.C.3.1.1.34）和从大鼠肝脏灌流液中纯化的肝脂肪酶对乳化的甘油三[9,10-³H]油酸酯的脂解作用，该作用是磷脂酰胆碱分子种类和乳剂胆固醇含量的函数。总体而言，两种酶的活性在摩尔基础上相似。当胆固醇含量较低时，用鸡蛋磷脂酰胆碱或饱和（二肉豆蔻酰、二棕榈酰和二硬脂酰）磷脂酰胆碱制成的乳剂，脂蛋白脂肪酶的初始脂解速率也相当。将乳剂中的胆固醇含量从2 - 3摩尔百分比增加到7 - 14摩尔百分比，会降低用饱和磷脂酰胆碱制成的乳剂中脂蛋白脂肪酶对三油精的脂解作用。在由饱和磷脂酰胆碱制成的乳剂中，大鼠肝脂肪酶比脂蛋白脂肪酶对胆固醇增加更敏感。在较长孵育期间维持三油精脂解的能力在不同乳剂和两种酶之间存在显著差异。淋巴乳糜微粒对两种酶而言都是比任何一种乳剂更好的底物。
