The coelomic hemerythrin of siphonosoma cumanense

Abstract

1. 1. Hemerythrocytes of Siphonosoma cumanense contain a hemerythrin which is resolved into three molecular weight components in gel chromatography. 2. 2. The majority of the protein is a trimer which is in equilibrium with a monomer, of the usual size. 3. 3. Further assembly occurs, to achieve a molecular weight in the region of 180,000. 4. 4. The hemerythrin subunits are oligodisperse with respect to charge as well, isoelectric focusing revealing three major monomer components. 5. 5. Electronic absorption and circular dichroism spectrescopy show the active site to be conserved in comparison with other hemerythrins, and indicate a high degree of α-helical secondary structure. 6. 6. The major protein component contains one cysteine per subunit, which reacts with organomercury(II) reagents, leading to dissociation of the trimer. © 1982.