K6Lipoproteins

1、K6 Lipoproteinslipoproteins 脂脂蛋白蛋白 apolipoprotein 载载指指蛋白蛋白chylomicron (CM) 乳糜微粒乳糜微粒 very low density lipoprotein(VLDL)极低密度脂蛋白极低密度脂蛋白intermediate density lipoprotein 中间密度脂蛋白中间密度脂蛋白low density lipoprotein (LDL) 低密度脂蛋白低密度脂蛋白high density lipoprotein (HDL) 高密度脂蛋白高密度脂蛋白atherosclerosis 动脉粥样硬化动脉粥样硬化 familia

2、l hypercholesterolemia 家族性家族性高高胆固醇胆固醇血症血症1 Structure and function Triacylglycerols, phospholipids and cholesterol are relatively insoluble in aqueous solution (水溶液水溶液). Hence, they are transported around the body in the blood as components of lipoproteins. The protein components of lipoproteins are

3、called apolipoproteins (apo，载脂蛋白，载脂蛋白). 超离心法分类超离心法分类电泳法分类电泳法分类乳糜微粒（乳糜微粒（chylomicrons, CM）乳 糜 微 粒乳 糜 微 粒（CM）极低密度脂蛋白（极低密度脂蛋白（VLDL）（）（very low density lipoproteins）前前 - 脂 蛋 白脂 蛋 白（pre- -Lp）中 间 密 度 脂 蛋 白 （中 间 密 度 脂 蛋 白 （ I D L ）（Intermediate density Lp）中间中间 -脂蛋白脂蛋白低密度脂蛋白（低密度脂蛋白（LDL）（）（low density Lp） -脂

4、蛋白（脂蛋白（ -Lp）高密度脂蛋白（高密度脂蛋白（HDL）（）（high density Lp） -脂蛋白（脂蛋白（ -Lp） Separation of plasma lipoproteins by electrophoresis on agarose gel组成份组成份CMVLDLLDLHDL蛋白质蛋白质292150甘油三酯甘油三酯（TG）80-9550-70114胆 固 醇胆 固 醇（Ch）2782胆固醇酯胆固醇酯（CE）51240-4220磷脂磷脂（PL）7182224人空腹血人空腹血浆中含量浆中含量(mg/dl)痕量痕量13020020040050130electron micro

5、scope The function of lipoproteinCM: They transport dietary (exogenous) triacylglycerols and cholesterol from the intestines to other tissues in the body.VLDL: transport internally produced (endogenous) triacylglycerols and cholesterol from the liver to the tissues.LDL: transport cholesterol from th

6、e liver to the tissues.HDL: transport endogenous cholesterol from the tissues to the liver. 2 Chylomicrons3 hydrolyzed by lipoprotein lipase1 synthesis 2 mature 4 form CM remnant5 receptor- mediated endocytosis CMs are synthesized in the intestine.3 VLDLs, IDLs and LDLs The synthesis of VLDL1 synthe

7、sis 2 mature 3 hydrolyzed by lipoprotein lipase4 form IDL5 form LDL LDL metabolism Levels of cholesterol regulate the Ch level in cell1 decrease 2 inhibit Michael Brown and Joseph Goldstein were awarded Nobel prize in 1985 for their work on LDL receptors.4 HDLs lecithin-cholesterol acyl transferase

8、(LCAT) Q9: Why LDL is called “ bad lipoprotein” whereas HDL is known as “ good lipoprotein” ? VLDLLDLHDLCholesterolHeartLiver “BAD” Deposit Excretion “Good” Forward and reverse cholesterol transport 5 Atherosclerosis Atherosclerosis is characterized by the presence of cholesterol-rich arterial thick

9、enings. This disease begins with the intracellular deposition of lipids, mainly cholesterol esters, in the smooth muscle cells of the arterial wall. If blockages occur in the coronary arteries, the result is a myocardial infarction or heart attack.6 Familial hypercholesterolemia Familial hypercholesterolemia is an inherited disorder in which homozygotes have a markedly elevated level of cholesterol in their blood, whilst in hetero