中文摘要：

目的了解不易感动脉粥样硬化动物树鼩的脂蛋白脂肪酶的结构和活性特点，并与其它种属比较，探讨脂蛋白脂肪酶在树鼩独特脂代谢中的作用。方法以树鼩脂肪细胞mRNA反转录获得的cDNA一链为模板，应用SMART-RACE技术获得树鼩脂蛋白脂肪酶的cDNA序列并推导出其氨基酸序列；实时定量PCR方法检测树鼩脂蛋白脂肪酶mRNA在各组织中的分布；真核表达树鼩和人脂蛋白脂肪酶蛋白，放射性同位素法测定二者的活性并比较。结果树鼩脂蛋白脂肪酶cDNA序列全长为3293bp，其中编码区1437bp，编码20个氨基酸的信号肽和458个氨基酸的成熟蛋白，该成熟蛋白N-端比人脂蛋白脂肪酶多10个氨基酸。树鼩脂蛋白脂肪酶与其它哺乳类动物的氨基酸序列同源性大于90%，功能域高度保守。树鼩脂蛋白脂肪酶的组织表达谱比较广泛，在心肌和脂肪组织中大量表达，但在骨骼肌中未检测到，却在肝脏中有中低水平表达，与人脂蛋白脂肪酶在这两种组织中的表达相反。活性测定结果显示，树鼩脂蛋白脂肪酶活性显著高于人（7.67倍），这与测定的树鼩血浆低甘油三酯水平相符。结论树鼩的高活性脂蛋白脂肪酶可能是其血浆低水平甘油三酯的主要原因。

英文摘要：

Aim To understand the features of lipoprotein hpase （ LPL） and its role in the distinctive hpid metabolism in tree shrew, which is considered to be an animal protected from atherosclerosis. Methods cDNA clones of tree shrew lipoprotein hpase were isolated from adipose tissue mRNA, benefiting from SMART-RACE technique. The tissue distribution of lipoprotein hpase in tree shrew was identified by Real-Time PCR. The activities of lipoprotein hpase from tree shrew and human expressed in eukaryecytes were measured by Radioactive Substrate Emulsion method, respectively. Results The nucleotide sequence of tree shrew LPL covered 3 293 bp, including a 1 437 bp coding region, which encoded a 20 residues predicted signal pepetide and a 458 residues mature protein that was ten residues longer than that of human at N-terminus. The homology of amino acid sequences of hpoprotein hpase from tree shrew and other mammalian species .was more than 90%, highly conserved in functional domains. LPL was expressed in many tissues in tree shrew, highly in cardiac muscle and adipose tissue. In despite of no expression in skeletal muscle, there was less-medium expression in liver, distinctly different from human LPL which was expressed in the contrary way in these two tissues. The tree shrew LPL activity was remarkably higher （7.67 times ） than that of human LPL, consistent with lower triglyceride concentration in tree shrew plasma compared with human. Conclusion The higher LPL activity in tree shrew should greatly attribute to its lower plasma triglyceride levels.