Abstract
Rare metals such as vanadium and cobalt are dissolved in sea water at very low levels. Ascidians are known to accumulate high levels of vanadium, a rare metal, selectively. The concentration of vanadium reaches 350 mM corresponding to 107 times the vanadium concentration in sea water. Recently, we have isolated vanadium-associated proteins, 12.5 kDa and 15 kDa, that are thought as the key to the solution of the mechanism, from ascidian blood cells and cloned cDNA encoding the proteins. We are carrying forward a scheme to elucidate the accumulation mechanisms of vanadium by ascidians and to apply the mechanism to leaching out rare metals from sea water.
