Løvstad Rolf A
Department of Medical Biochemistry, University of Oslo, PO Box 1112 Blindern, 0317 Oslo, Norway.
Biometals. 2004 Apr;17(2):111-3. doi: 10.1023/b:biom.0000018362.37471.0b.
Serum albumin (human, bovine) has a specific Cu(II)-ion binding site, and is proposed to act as a copper transport protein in blood plasma. Human transferrin, normally about 30% saturated with iron in vivo, has two sites/molecule capable of complexing Cu(II); one more strongly than the other (Hirose et al. 1996). The present study shows that this binding site has a slightly stronger affinity for Cu(II) than that on the albumins. However, both human- and bovine albumin could take up part of the transferrin bound Cu(II), the second order rate constant for the reaction estimated to 12 mM(-1) min(-1) for both species. In vivo the albumin concentration is considerably higher than that of iron-free transferrin, and it seems unlikely that the latter can compete with albumin for non-ceruloplasmin cupric ions.
血清白蛋白（人源、牛源）具有特定的铜（II）离子结合位点，被认为在血浆中充当铜转运蛋白。人转铁蛋白在体内通常约30%被铁饱和，每个分子有两个能够络合铜（II）的位点；其中一个比另一个结合力更强（Hirose等人，1996年）。本研究表明，该结合位点对铜（II）的亲和力略强于白蛋白上的结合位点。然而，人源和牛源白蛋白都能摄取部分与转铁蛋白结合的铜（II），两种白蛋白该反应的二级速率常数估计均为12 mM⁻¹ min⁻¹。在体内，白蛋白浓度远高于无铁转铁蛋白，后者似乎不太可能与白蛋白竞争非铜蓝蛋白铜离子。
