van Antwerpen R, Salvador K, Tolman K, Gentry C
Department of Biochemistry, University of Arizona, Tucson 85721, USA.
Insect Biochem Mol Biol. 1998 May-Jun;28(5-6):399-408. doi: 10.1016/s0965-1748(98)00012-5.
A plasma membrane preparation of Manduca sexta ovarian follicles was shown to contain lipoprotein lipase activity that hydrolyzes the diacylglycerol moiety of the hemolymph lipoprotein, lipophorin. Kinetic analysis demonstrated that low density lipophorin (LDLp) is a better substrate for the identified lipase activity than high density lipophorin (HDLp). The activity has a pH optimum of 9-9.5 and is partially inhibited by NaCl concentrations higher than 0.5 M. Diisopropylfluorophosphate (DFP) inhibits the membrane bound lipoprotein lipase activity completely and irreversibly. Incubation of follicle plasma membranes with [3H]-DFP radiolabels a 100-kDa membrane protein that may represent the lipoprotein lipase. The present results suggest that lipoprotein lipase activity may play an important role in the uptake of lipids by M. sexta oocytes.
烟草天蛾卵巢卵泡的质膜制剂显示含有脂蛋白脂肪酶活性，该酶可水解血淋巴脂蛋白——脂转运蛋白的二酰基甘油部分。动力学分析表明，低密度脂转运蛋白（LDLp）比高密度脂转运蛋白（HDLp）更适合作为已鉴定的脂肪酶活性的底物。该活性的最适pH为9 - 9.5，当NaCl浓度高于0.5 M时会受到部分抑制。二异丙基氟磷酸酯（DFP）完全不可逆地抑制膜结合脂蛋白脂肪酶活性。用[3H]-DFP孵育卵泡质膜会使一种100 kDa的膜蛋白放射性标记，该蛋白可能代表脂蛋白脂肪酶。目前的结果表明，脂蛋白脂肪酶活性可能在烟草天蛾卵母细胞摄取脂质过程中发挥重要作用。
