Parks J S, Thuren T Y, Schmitt J D
Department of Comparative Medicine, Bowman Gray School of Medicine, Winston-Salem, NC 27157-1040.
J Lipid Res. 1992 Jun;33(6):879-87.
Phospholipids isolated from the plasma of monkeys fed a diet enriched in fish oil were poor substrates for cholesteryl ester (CE) synthesis by the lecithin:cholesterol acyltransferase (LCAT) reaction relative to those from animals fed a lard containing diet when the phospholipids were used for the preparation of recombinant particles by cholate dialysis (Parks, J. S., B. C. Bullock, and L. L. Rudel. 1989. J. Biol. Chem. 264: 2545-2551). The purpose of the present study was to directly test the influence of eicosapentaenoic acid (20:5 n-3) and docosahexaenoic acid (22:6 n-3) in the sn-2 position of phosphatidylcholine (PC) on the activity of LCAT. PC species containing 1-palmitoyl-2-oleoyl PC (POPC), 1-palmitoyl-2-linoleoyl PC (PLPC), 1-palmitoyl-2-arachidonoyl PC (PAPC), 1-palmitoyl-2-eicosapentaenoyl PC (PEPC), or 1-palmitoyl-2-docosahexaenoyl PC (PDPC) were purchased or synthesized and made into recombinant particles of uniform size and composition with [14C]cholesterol and apoA-I using the cholate dialysis procedure. The recombinant particles (PC:cholesterol:apoA-I molar ratio = 42:1.9:1) exhibited the following order of reactivity towards purified human LCAT in vitro: POPC greater than PLPC greater than PEPC = PAPC greater than PDPC. The apparent Vmax/Km for recombinant particles containing PEPC and PDPC was 17% and 7% that of particles containing POPC, respectively. There was a linear decrease in CE formation when the percentage of PEPC or PDPC was increased from 0 to 100% relative to POPC in recombinant particles with a constant PC:cholesterol:apoA-I molar ratio, suggesting that the PEPC and PDPC were competitive inhibitors of the LCAT reaction.(ABSTRACT TRUNCATED AT 250 WORDS)
与用含猪油饮食喂养的动物血浆中分离出的磷脂相比，从食用富含鱼油饮食的猴子血浆中分离出的磷脂，在通过卵磷脂胆固醇酰基转移酶（LCAT）反应合成胆固醇酯（CE）时，作为底物的效果较差。这是在通过胆酸盐透析制备重组颗粒时得出的结论（帕克斯，J.S.，B.C.布洛克，和L.L.鲁德尔。1989年。《生物化学杂志》264:2545 - 2551）。本研究的目的是直接测试磷脂酰胆碱（PC）的sn - 2位上的二十碳五烯酸（20:5 n - 3）和二十二碳六烯酸（22:6 n - 3）对LCAT活性的影响。含有1 - 棕榈酰 - 2 - 油酰基PC（POPC）、1 - 棕榈酰 - 2 - 亚油酰基PC（PLPC）、1 - 棕榈酰 - 2 - 花生四烯酰基PC（PAPC）、1 - 棕榈酰 - 2 - 二十碳五烯酰基PC（PEPC）或1 - 棕榈酰 - 2 - 二十二碳六烯酰基PC（PDPC）的PC种类是购买或合成的，并使用胆酸盐透析程序与[¹⁴C]胆固醇和载脂蛋白A - I制成大小和组成均匀的重组颗粒。重组颗粒（PC:胆固醇:载脂蛋白A - I摩尔比 = 42:1.9:1）在体外对纯化的人LCAT表现出以下反应活性顺序：POPC＞PLPC＞PEPC = PAPC＞PDPC。含有PEPC和PDPC的重组颗粒的表观Vmax/Km分别是含有POPC颗粒的17%和7%。在PC:胆固醇:载脂蛋白A - I摩尔比恒定的重组颗粒中，当PEPC或PDPC相对于POPC的百分比从0增加到100%时，CE形成呈线性下降，这表明PEPC和PDPC是LCAT反应的竞争性抑制剂。（摘要截短至250字）
