Sato K, Suzuki K, Akiba Y
Department of Animal Science, Faculty of Agriculture, Tohoku University, Aobaku, Japan.
Comp Biochem Physiol A Mol Integr Physiol. 1998 Feb;119(2):569-73. doi: 10.1016/s1095-6433(97)00468-6.
Kinetic parameters of chicken and rat lipoprotein lipase (LPL) were determined in the incubation in vitro with various monoacid triacylglycerol emulsion and plasma lipoproteins. In rat- and chicken-LPL there is an inverse relationship between the hydrolytic rate by both LPL and the increased acyl-chain unsaturation of monoacid triacylglycerol; C18:1>C18:2>C18:3. The rat LPL catalyzed hydrolysis of saturated monoacid triaclyglycerol increased with an increase of chain length as C16>C14>C12, whereas in chicken LPL hydrolytic rate of C12 was higher than C14 and C16 triaclyglycerol. Vmax of rat- and chicken-LPL for chylomicron and VLDL were higher but apparent Km for those were lower than other lipoproteins. In chicken, Vmax and apparent Km of LPL for VLDL were almost the same as those for chylomicron, whereas in rat, Vmax of LPL for VLDL was twice that of chylomicron with the same apparent Km. The chicken and rat VLDL with different particle size prepared by Bio-Gel A50 gel chromatography were similarly hydrolyzed by LPL, while the hydrolysis of small chicken-chylomicron particles was inclined to be higher than that of the large particles. These results show species differences between chickens and rats in the substrate specificity of LPL.
通过在体外与各种单酸三酰甘油乳液和血浆脂蛋白共同孵育，测定了鸡和大鼠脂蛋白脂肪酶（LPL）的动力学参数。在大鼠和鸡的LPL中，LPL的水解速率与单酸三酰甘油酰基链不饱和度的增加呈负相关；C18:1>C18:2>C18:3。大鼠LPL催化的饱和单酸三酰甘油水解随着链长的增加而增加，顺序为C16>C14>C12，而在鸡LPL中，C12三酰甘油的水解速率高于C14和C16三酰甘油。大鼠和鸡的LPL对乳糜微粒和极低密度脂蛋白（VLDL）的Vmax较高，但对它们的表观Km低于其他脂蛋白。在鸡中，LPL对VLDL的Vmax和表观Km与对乳糜微粒的几乎相同，而在大鼠中，LPL对VLDL的Vmax是乳糜微粒的两倍，表观Km相同。通过Bio-Gel A50凝胶色谱法制备的不同粒径的鸡和大鼠VLDL被LPL同样程度地水解，而小鸡乳糜微粒小颗粒的水解倾向于高于大颗粒。这些结果表明鸡和大鼠在LPL的底物特异性方面存在种属差异。
