Boyles J K, Notterpek L M, Wardell M R, Rall S C
Gladstone Foundation Laboratories, San Francisco CA 94140-0608.
J Lipid Res. 1990 Dec;31(12):2243-56.
We recently described an unknown apolipoprotein that is present on the lipoprotein particles isolated from regenerating rat sciatic nerves. In the regenerating nerve, the concentration of this apolipoprotein rises 500-fold over its concentration in the normal nerve. In this report we have identified the apolipoprotein by partial amino acid sequence analysis as apolipoprotein (apo) D. Characterization of rat apoD by sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed it to be composed of a series of molecular weight isoforms of between 27 kDa and 31 kDa that increase 2 kDa in apparent molecular mass upon reduction. Rat apoD has multiple isoelectric points between pH 4.05 and 4.37, apparently resulting from N-linked glycosylation. In the rat, unlike the human, little apoD is found in plasma. However, immunocytochemical localization of apoD in 12 tissues (liver, kidney, bladder, adrenal, cerebrum, duodenum, testis, lung, spleen, pancreas, heart, and skin) showed that a variety of cells contained substantial levels of apolipoprotein. The broad distribution of apoD suggests that it may play a general role in cellular metabolism. Moreover, many of the same cell types varied dramatically in their content of apoD in different tissues, suggesting that the uptake or secretion of apoD by cells is regulated.
我们最近描述了一种未知的载脂蛋白，它存在于从再生大鼠坐骨神经中分离出的脂蛋白颗粒上。在再生神经中，这种载脂蛋白的浓度比正常神经中的浓度升高了500倍。在本报告中，我们通过部分氨基酸序列分析将该载脂蛋白鉴定为载脂蛋白（apo）D。通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳对大鼠apoD进行表征，结果显示它由一系列分子量在27 kDa至31 kDa之间的同工型组成，还原后表观分子量增加2 kDa。大鼠apoD在pH 4.05至4.37之间有多个等电点，显然是由N-连接糖基化导致的。在大鼠中，与人类不同，血浆中几乎没有发现apoD。然而，apoD在12种组织（肝脏、肾脏、膀胱、肾上腺、大脑、十二指肠、睾丸、肺、脾脏、胰腺、心脏和皮肤）中的免疫细胞化学定位显示，多种细胞含有大量的载脂蛋白。apoD的广泛分布表明它可能在细胞代谢中发挥普遍作用。此外，许多相同类型的细胞在不同组织中的apoD含量差异很大，这表明细胞对apoD的摄取或分泌是受调控的。
