Stoichiometry of Fe(II) oxidation during ceruloplasmin-catalyzed loading of ferritin.
Stoichiometry of Fe(II) oxidation during ceruloplasmin-catalyzed loading of ferritin.
复制标题
铜蓝蛋白催化铁蛋白负载过程中 Fe(II) 氧化的化学计量。
DOI：
10.1016/0003-9861(92)90121-c
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发表时间：
1992
影响因子：
3.9
通讯作者：
Aust,SD
中科院分区：
文献类型：
--
作者：
deSilva,D;Aust,SD
铜蓝蛋白催化铁进入载铁蛋白，其化学计量比为3.8Fe(II)O2。当使用不同含铁量的铁蛋白时，该值保持不变。与铁蛋白形成的“晶体生长”模型相反，在没有铜蓝蛋白的情况下，没有观察到全铁蛋白中铁的掺入。Fe(II)O2。在没有铜蓝蛋白的情况下，在HEPES缓冲液中，脱铁蛋白和全铁蛋白的铁掺入比接近2，表明形成了还原的氧物种。在这个缓冲液中顺序加载铁蛋白导致蛋白质的氧化增加，这是通过羰基形成来衡量的。用铜蓝蛋白连续负载铁蛋白不会导致蛋白质氧化，最多有2300个铁原子被结合到大鼠肝脏铁蛋白中。这与体内注射铁后大鼠肝脏铁蛋白中发现的最大铁量相对应。这些结果为铜蓝蛋白作为脱铁蛋白和全铁蛋白结合铁的有效催化剂提供了证据。讨论了这些发现可能具有生理学意义的可能性。
Ceruloplasmin catalyzed the incorporation of iron into apoferritin with a stoichiometry of 3.8 Fe (II) O 2. This value remained the same when ferritin containing varying amounts of iron was used. Contrary to the “crystal growth” model for ferritin formation, no iron incorporation into holoferritin was observed in the absence of ceruloplasmin. Fe (II) O 2. This ratios close to 2 were obtained for iron incorporation into apo-and holoferritin in Hepes buffer, in the absence of ceruloplasmin, indicating the formation of reduced oxygen species. Sequential loading of ferritin in this buffer resulted in increasing oxidation of the protein as measured by carbonyl formation. Sequential loading of ferritin using ceruloplasmin did not result in protein oxidation and a maximum of about 2300 atoms of iron were incorporated into rat liver ferritin. This corresponded to the maximum amount of iron found in rat liver ferritin in vivo after injection with iron. These results provide evidence for ceruloplasmin as an effective catalyst for the incorporation of iron into both apo-and holoferritin. The possibility that these findings may have physiological significance is discussed.