Abstract
The iron concentration, oxidation state, and distribution in blood plasma and blood cells of three iron containing tunicates were determined. Preliminary studies are reported on the possible role of plasma proteins in iron uptake.
Iron(II) concentration in the millimolar range was found in the blood cell cytoplasm of all three species; no iron(III) in solution was detected in blood cells. Over 70% of the total iron in the cells is associated with the membranes.
Although the iron concentration in S. clava blood cells is substantially greater than that in B. ovifera cells, the iron to protein ratio by weight is similar in both species. SDS-electrophoresis of B. ovifera blood showed two protein subunits common to both plasma and blood cells. These two subunits are most likely the major components of the high molecular weight protein found in the plasma. This protein was shown to bind iron(III) when iron(III) citrate was added to the plasma.