Absorption of Vanadium by Tunicates
Absorption of Vanadium by Tunicates
复制标题
被囊类动物对钒的吸收
作者:
M. Kalk
THE accumulation of vanadium by certain species of tunicates is a case of extremely selective absorption of a rare element from the sea1, where it occurs at its highest valency: as vanadate anion or perhaps vanadyl cation2. In tunicate tissues the chromogen, hsemo-vanadin, is a reducing substance containing trivalent vanadium complexed with sulphate and chelated with the amino groups of protein3. The reducing properties facilitate the detection of vanadium in electron-micrographs of tissues fixed in osmic acid. It has been suggested3 that the surfaces of blood cells bind vanadate that has entered the blood plasma without any selective absorption. My evidence pin-points the site of chelation in the blood cells and suggests selective adsorption of vanadyl ions.