Nagaoka Megumi Hamano, Akiyama Hiroshi, Maitani Tamio
National Institute of Health Sciences, Kamiyoga 1-18-1, Setagaya, Tokyo 158-8501, Japan.
Analyst. 2004 Jan;129(1):51-4. doi: 10.1039/b311013n. Epub 2003 Nov 27.
Vanadium (V) is an essential metal for mammals. It has different valence states. In blood, V is bound to transferrin (Tf), a glycoprotein that has two metal-binding sites (C-lobe site and N-lobe site). In the present study, the binding patterns of V to serum Tf were analyzed by combined on-line HPLC and high-resolution ICP-MS (HPLC/HR-ICP-MS). The levels of (51)V, (56)Fe and (32)S, which are interfered with polyatomic ions such as (35)Cl(16)O(+), (38)Ar(13)C(+) and (37)Cl(14)N(+), (40)Ar(16)O(+) and (40)Ca(16)O(+), and (16)O(2)(+), respectively, when using quadrupole ICP-MS, could be monitored simultaneously by HR-ICP-MS at a resolution of m/[capital Delta]m= 4000. Sample (a 1 ml portion of serum from a healthy person or 2 mg of human serum Tf (hTf)) was directly subjected to HPLC equipped with an anion-exchange column. V in human serum without any in vitro V spike was detected as V(C)-Tf (V bound to C-lobe site of Tf) and metal(2)-Tf. Since V(iii) was most favorable in terms of the binding to hTf in the presence of bicarbonate and V bound to the C-lobe site of hTf was detected only in the case of V(iii) among the three valence states of V, it was suggested that a part, at least, of V in the V(C)-Tf in healthy human serum may be present as V(iii), in addition to the generally accepted V(iv).
钒（V）是哺乳动物必需的金属。它具有不同的价态。在血液中，V与转铁蛋白（Tf）结合，转铁蛋白是一种具有两个金属结合位点（C叶位点和N叶位点）的糖蛋白。在本研究中，通过在线HPLC和高分辨率ICP-MS联用（HPLC/HR-ICP-MS）分析了V与血清Tf的结合模式。在使用四极杆ICP-MS时，分别受到诸如（35）Cl（16）O（+）、（38）Ar（13）C（+）和（37）Cl（14）N（+）、（40）Ar（16）O（+）和（40）Ca（16）O（+）以及（16）O2（+）等多原子离子干扰的（51）V、（56）Fe和（32）S的水平，可通过分辨率为m/Δm = 4000的HR-ICP-MS同时监测。将样品（来自健康人的1 ml血清或2 mg人血清Tf（hTf））直接注入配备阴离子交换柱的HPLC中。在未进行任何体外V加标的人血清中，V被检测为V（C）-Tf（V与Tf的C叶位点结合）和金属（2）-Tf。由于在碳酸氢盐存在的情况下，V（iii）在与hTf的结合方面最有利，并且在V的三种价态中，仅在V（iii）的情况下检测到V与hTf的C叶位点结合，因此表明，除了普遍认可的V（iv）之外，健康人血清中V（C）-Tf中的V至少有一部分可能以V（iii）的形式存在。
