Intact human ceruloplasmin is required for the incorporation of iron into human ferritin.
Intact human ceruloplasmin is required for the incorporation of iron into human ferritin.
复制标题
将铁掺入人铁蛋白需要完整的人铜蓝蛋白。
DOI：
10.1006/abbi.2000.1952
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发表时间：
2000
期刊：
影响因子：
--
通讯作者：
Aust,SD
中科院分区：
文献类型：
--
作者：
VanEden,ME;Aust,SD
我们以前已经报道了几项研究的铁装载到铁蛋白的铜蓝蛋白使用蛋白质从大鼠。使用人血清铜蓝蛋白将铁装载到人铁蛋白中是复杂的，因为人铜蓝蛋白对蛋白水解非常敏感（T. P. Ryan，T. A. Grover和S. D. Aust，1992，Arch. Biochem. Biophys. 293，1-8）。本研究探讨了蛋白水解对人铜蓝蛋白将铁负载到人铁蛋白中的能力的影响。SDS-聚丙烯酰胺凝胶电泳显示一个主要的带与表观分子量为116 kDa的蛋白水解降解形式的血浆铜蓝蛋白与一个132 kDa的带的完整形式的酶。这两种酶都具有铁氧化酶活性，尽管蛋白水解降解的酶的活性比完整酶的活性低约两倍（4.9 nmol（min）− 1 vs 8.3 nmol（min）−1）。只有完整形式的血浆铜蓝蛋白能够催化铁加载到铁蛋白中，而不改变铁蛋白的物理特性的过程中。当铁蛋白单独与铁或与蛋白水解降解的血浆铜蓝蛋白和铁一起孵育时，观察到非变性PAGE凝胶中的异常迁移以及可检测的铁蛋白量的减少。得出的结论是，铜蓝蛋白的结构完整性所需的酶，以有效地催化铁加载到铁蛋白。
We have previously reported several studies on the loading of iron into ferritin by ceruloplasmin using proteins from rats. Loading iron into human ferritin using human serum ceruloplasmin is complicated by the fact that human ceruloplasmin is very susceptible to proteolysis (T. P. Ryan, T. A. Grover, and S. D. Aust, 1992, Arch. Biochem. Biophys. 293, 1–8). The present study investigated the effect of proteolysis on the ability of human ceruloplasmin to load iron into human ferritin. SDS–PAGE revealed one major band with an apparent molecular weight of 116 kDa for a proteolytically degraded form of ceruloplasmin versus a 132-kDa band for an intact form of the enzyme. Both forms of the enzyme possessed ferroxidase activity, although that of the proteolytically degraded enzyme was approximately twofold less than that of the intact enzyme (4.9 nmol (min)−1vs 8.3 nmol (min)−1). Only the intact form of ceruloplasmin was able to catalyze iron loading into ferritin without altering the physical characteristics of the ferritin protein during the process. Abnormal migration in nondenaturing PAGE gels, as well as a decrease in the amount of detectable ferritin protein, was observed when ferritin was incubated with iron alone or with proteolytically degraded ceruloplasmin and iron. It was concluded that the structural integrity of ceruloplasmin is required for the enzyme to effectively catalyze iron loading into ferritin.