Stability of free apolipoprotein A-1 concentration in serum, and its measurement in normal and hyperlipidemic subjects.
Stability of free apolipoprotein A-1 concentration in serum, and its measurement in normal and hyperlipidemic subjects.
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血清中游离载脂蛋白 A-1 浓度的稳定性及其在正常和高脂血症受试者中的测量。
DOI：
10.1093/clinchem/33.7.1163
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发表时间：
1987
影响因子：
9.3
通讯作者：
E. Gowland
中科院分区：
文献类型：
--
作者：
R. Neary;E. Gowland
游离载脂蛋白A-1(Free A-1)是一种含有载脂蛋白A-1(apo A-1)的低分子蛋白质和脂类复合体。用交叉免疫电泳法将高密度脂蛋白中的载脂蛋白A-1从载脂蛋白A-1中分离出来，并与用9mol/L尿素溶液稀释的参考血清(每升含1.45g载脂蛋白A-1)进行比较，以定量测定游离A-1。后一种处理产生的载脂蛋白A-1含有与游离A-1相同大小和电泳迁移率的蛋白质-脂质复合体。对平均游离A-1浓度为48 mg/L和138 mg/L的样品进行重复分析，日内精密度(CV)分别为9.1%和7.2%。我们还发现，血清或血浆中游离A-1的浓度在4摄氏度或冷冻时都不稳定。28例空腹健康受试者血浆游离A-1平均浓度为75.3(SD 13.6)mg/L，餐后升高无统计学意义。血清中游离载脂蛋白A-1的总比例为3.5%-8.1%，低于其他用放射免疫扩散法检测游离载脂蛋白A-1的报道的10%-30%。由于径向免疫扩散不能将游离A-1从高密度脂蛋白中分离出来，我们认为该技术高估了游离A-1。采用交叉免疫电泳法对76例高脂血症患者进行游离A-1测定。Fredrickson III和V型患者的游离A-1浓度显著升高(P<0.0001)。血清游离A-1与胆固醇和甘油三酯的相关性显著(P<0.005和P<0.001)。讨论了游离A-1在脂质代谢中的可能作用。
Free apolipoprotein A-1 (free A-1) is a low-molecular-mass complex of protein and lipid containing apolipoprotein A-1 (apo A-1). Using crossed immunoelectrophoresis, we separated free A-1 from the apo A-1 in high-density lipoproteins (HDL) and quantified free A-1 by comparison with a reference serum (containing 1.45 g of apo A-1 per liter) diluted in 9 mol/L urea solution. This latter treatment yields apo A-1 containing protein-lipid complexes of the same size and electrophoretic mobility as free A-1. Within-day precision (CV), determined by replicate analysis of two samples with mean free A-1 concentrations of 48 and 138 mg/L, was 9.1 and 7.2%, respectively. We also showed that the concentration of free A-1 is not stable in serum or plasma either at 4 degrees C or when frozen. The mean concentration of free A-1 in 28 fasted, healthy subjects was 75.3 (SD 13.6) mg/L. The postprandial increase was not statistically significant. The percentage of total apo A-1 in the free form in serum ranged from 3.5% to 8.1%, less than the 10% to 30% reported by others who used radial immunodiffusion to measure free A-1. Because radial immunodiffusion does not separate free A-1 from HDL, we believe that that technique overestimates free A-1. We also used crossed immunoelectrophoresis to measure free A-1 in 76 hyperlipidemic patients. Those with Fredrickson types III and V had significantly increased concentrations of free A-1 (P less than .0001). Correlations between free A-1 and cholesterol and triglycerides in serum were significant (P less than .005 and P less than .001, respectively). Possible roles for free A-1 in lipid metabolism are discussed.