Isolation, characterization, and uptake in human fibroblasts of an apo(a)-free lipoprotein obtained on reduction of lipoprotein(a).
Isolation, characterization, and uptake in human fibroblasts of an apo(a)-free lipoprotein obtained on reduction of lipoprotein(a).
复制标题
脂蛋白 (a) 还原获得的无 apo(a) 脂蛋白的分离、表征和人成纤维细胞的摄取。
作者：
V. Armstrong;A. Walli;D. Seidel
在非变性条件下用二硫苏糖醇处理天然人 Lp(a) 产生脂蛋白颗粒和无脂蛋白组分，可以通过 d 1.063 g/ml 超速离心或肝素-琼脂糖层析分离。该蛋白质成分仅对抗 Lp(a) 表现出抗原性，但对抗 B 不表现出抗原性。根据 SDS 聚丙烯酰胺凝胶电泳 (PAGE)，它是不均匀的，由两条带组成，一条分子量与 apoB 相似的主条带，一条分子量稍低的次条带。脂蛋白颗粒在电泳迁移率、脂蛋白组成、凝胶排阻色谱的表观分子量以及脱辅基蛋白含量方面与 LDL 相似；通过 SDS-PAGE 和免疫化学分析发现仅存在 apoB。该脂蛋白还被证明与 LDL 相同，在培养的人成纤维细胞中通过受体介导的 LDL 途径摄取，如 125 I 标记脂蛋白在 37 摄氏度下的浓度依赖性结合、内化和降解曲线的相似性所示。在受体介导途径的各个步骤中，正常 Lp(a) 不像其还原脂蛋白成分或 LDL 那样容易被吸收。降解试验中 Lp(a) 的最大容量仅为 LDL 的 25%，且 Km 高出四倍。因此，LDL 受体介导的途径可能不是 Lp(a) 体内清除的主要途径。这些研究表明，Lp(a) 本质上是一种 LDL 颗粒，蛋白质 (a) 通过二硫键与 apoB 连接。
Treatment of native human Lp(a) under nondenaturing conditions with dithiothreitol yielded both a lipoprotein particle and a lipid-free protein component that could be separated by either ultracentrifugation at d 1.063 g/ml or heparin-Sepharose chromatography. The protein component only showed antigenicity against anti-Lp(a) but not against anti-B. It was heterogeneous according to SDS polyacrylamide gel electrophoresis (PAGE) consisting of two bands, a major band with molecular weight similar to apoB and a minor band with slightly lower molecular weight. The lipoprotein particle was similar to LDL with regard to its electrophoretic mobility, lipid-protein composition, its apparent molecular weight according to gel-exclusion chromatography, and its apoprotein content; only apoB was found to be present by SDS-PAGE and immunochemical analysis. This lipoprotein also proved to be identical to LDL in its uptake by the receptor-mediated LDL-pathway in cultured human fibroblasts as shown by the similarity of the concentration-dependent binding, internalization, and degradation curves at 37 degrees C of the 125I-labeled lipoproteins. Normal Lp(a) was not taken up as readily as either its reduced lipoprotein component or LDL in the various steps of the receptor-mediated pathway. The maximal capacity for Lp(a) in the degradation assay was only 25% of that of LDL and it had a fourfold higher Km. It is therefore probable that the LDL-receptor-mediated pathway is not a major route for the clearance of Lp(a) in vivo. These studies suggest that Lp(a) is, in essence, an LDL-particle to which the protein (a) is attached through disulfide bonds to apoB.
培养的成纤维细胞对 Lp (a) 脂蛋白的摄取。
DOI：
10.1016/s0006-291x(81)80179-9
发表时间：
1981
影响因子：
3.1
作者：
Floren,CH;Albers,JJ;Bierman,EL
通讯作者：
Bierman,EL
影响因子：
6.5
作者：
C. Drevon;A. Attie;S. Pangburn;D. Steinberg
通讯作者：
C. Drevon;A. Attie;S. Pangburn;D. Steinberg
人血浆脂蛋白的异质性（a）。
DOI：
--
发表时间：
1984
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Fless,GM;Rolih,CA;Scanu,AM
通讯作者：
Scanu,AM