Über das Vanadiumchromogen des Ascidienblutes.

Abstract

Blood cells of an ascidian (Phallusia mammillata) contain an organic vanadium-compound dissolved in a strongly acid liquid, the acidity being due to the presence of H2SO4 in about 3% concentration. The compound (very likely a protein in spite of the low N-percentage) had a percentage composition of C = 38.96, H=4.65, N = 7.45, V = 10.16. To judge according to the values of the "N-distribution" (values in the original) pyrrol rings are chiefly present. The V-chromogen is not an O2 carrier like Hb. Its genuine solution has extremely strong reducing powers. It could be titrated with methylene blue and with indigo. In this way and in accordance with experiments of inorganic V-salts of different valencies it is stated that the V in the chromogen molecule is fixed in the V" stage. Considering the biological function of the V-compound the author points out: (1) the very low CO2 content of the blood in comparison with that of the surrounding sea water, which is in contrast with all known findings in other lower sea animals; and (2) the fact that ascidians are the only animals which produce real cellulose. With utmost reserve the author considers the possibility that Phallusia might partly consume CO2, reducing it to carbohydrate, and build up cellulose under the influence of the V-chromogen and perhaps also light. The first respiratory experiments done to test this idea met with great technical difficulties and did not permit any decision.