Extraction of a Vanadium-Binding Substance (Vanadobin) from the Blood Cells of Several Ascidian Species.

A combination of techniques, including chromatography on Sephadex G-15 and SE-cellulose columns and neutron activation analysis for vanadium determination, was used to extract (at low pH) a vanadium-binding substance (vanadobin) from the blood cells of the ascidian species: Ascidia ahodori OKA, A. gemmata SLUITER, A. zara OKA, Corella japonica HERDMAN, and Ciona intestinalis (LINNE). In general, ascidians can be classified into two different categories based on vanadium content: species of the family Ascidiidae contain high levels of vanadium, whereas those in the Cionidae and Corellidae do not always have such high amounts. Because Ciona intestinalis and Corella japonica do have vanadobin in their blood cells, vanadobin may well be a universal complex in ascidians, having the role of accumulating vanadium in blood cells and maintaining its concentration. The blood cells of A. gemmata contained the highest amount of vanadium. Vanadobin extracted from these cells exhibits absorption spectra, not only in the ultraviolet region, but also in the visible region; such spectra correspond to those observed in vanadium complexes in oxidation states of +3 and +4.