Abstract:Abstract The chemical and physical properties of the hemoglobin of the polychaete annelid Arenicola cristata have been studied. Gel filtration and ultracentrifugation indicate that it has a molecular ...Abstract The chemical and physical properties of the hemoglobin of the polychaete annelid Arenicola cristata have been studied. Gel filtration and ultracentrifugation indicate that it has a molecular weight of 2.85 x 106 and is composed of 12 subunits of molecular weight 230,000. The iron content corresponds to the presence of 1 mole of heme per 26,000 g of protein. Acrylamide gel electrophoresis in sodium dodecyl sulfate indicates that there are two polypeptide chains with masses of 13,000 and 14,000 daltons. These data suggest that two chains are involved in binding one heme and that there are approximately 96 hemes per molecule. Amino acid analyses of the molecule and its individual chains have been performed revealing the presence of three disulfide groups and one free sulfhydryl group per heme unit. Oxygenation studies show that the molecule is highly cooperative with a Hill coefficient close to six, but it has a small Bohr effect.Read More