Physiological Roles of Vanadium-Binding Substance Extracted from Ascidian Blood Cells

海鞘血细胞在海水中积累的钒超过其水平的100万倍，这一不同寻常的能力吸引了来自不同研究领域的研究人员的兴趣。在这个实验过程中，我们成功地从几种类型的海鞘血细胞中分离出了高酸性和含钒的血细胞(钒细胞)，采用密度梯度离心法和ESR光谱相结合的方法。还发现该晶胞含有+3和+4两种氧化态的钒，其比例为97.6：2.4。此外，ESR光谱数据表明，钒细胞中存在一种与钒结合的物质--钒多宾，并具有将钒(V)还原为钒(IV)的能力。

The unusual ability of ascidian blood cells to accumulate vanadium in excess of one million times its level in seawater has attracted the interest of investigators from various fields of study. During the course of this experiment, we have succeeded to isolate highly acidic and vanadium-containing blood cells (vanadocytes) from among several types of ascidian blood cell, using a combined approach of density-gradient centrifugation and ESR spectrometry. It has been also revealed that this cell type contains vanadium in both +3 and +4 oxidation states, with a ratio of 97.6 : 2.4. Furthermore, a vanadium-binding substance, vanadobin, was revealed to exist in the vanadocytes and to have the ability to reduce vanadate (V) to vanady (IV), as clarified by the data obtained by ESR spectrometry.