Gordon D T, Leinart A S, Cousins R J
Am J Physiol. 1987 Mar;252(3 Pt 1):E327-33. doi: 10.1152/ajpendo.1987.252.3.E327.
The distribution of newly absorbed copper among serum proteins obtained from the portal circulation of rats was examined by conventional and high-performance gel filtration chromatography, affinity chromatography, and Western blotting. Within 10-30 min after being administered by gavage or directly into the intestine, 67Cu and 64Cu, respectively, were recovered in the albumin fraction. By 8 h after administration of the radionuclides, virtually all of the radioactivity was found with ceruloplasmin. Affigel blue fractionation and subsequent Superose-6 chromatography further demonstrated that all of the copper in the albumin-containing fractions was in fact bound to this protein rather than high molecular weight moieties. Vascular perfusion of the isolated rat intestine, where 64Cu was infused into the lumen, showed that newly absorbed 64Cu in the vascular perfusate collected from the cannulated portal vein was associated with albumin. Uptake of radioactivity by isolated rat liver parenchymal cells from medium containing rat serum with 67Cu bound to albumin was demonstrated. In vitro binding of 64Cu to serum proteins that were transferred to nitrocellulose by Western blotting techniques showed that albumin is essentially the only protein that binds appreciable amounts of copper. The data suggest that albumin is the plasma protein that is responsible for the initial transport of copper after absorption.
通过传统和高效凝胶过滤色谱法、亲和色谱法以及蛋白质印迹法，研究了从大鼠门静脉循环中获取的血清蛋白中新吸收铜的分布情况。经口灌胃或直接注入肠道后10 - 30分钟内，分别在白蛋白组分中回收了67Cu和64Cu。在给予放射性核素8小时后，几乎所有的放射性都出现在铜蓝蛋白中。Affigel blue分级分离及随后的Superose - 6色谱分析进一步表明，含白蛋白组分中的所有铜实际上都与该蛋白结合，而非高分子量部分。将64Cu注入肠腔的离体大鼠肠道血管灌注实验表明，从插管门静脉收集的血管灌注液中新吸收的64Cu与白蛋白相关。已证实离体大鼠肝实质细胞能从含有与白蛋白结合的67Cu的大鼠血清的培养基中摄取放射性。通过蛋白质印迹技术转移至硝酸纤维素膜上的血清蛋白与64Cu的体外结合实验表明，白蛋白基本上是唯一能结合可观量铜的蛋白。这些数据表明，白蛋白是负责吸收后铜初始转运的血浆蛋白。
