Structure and oxygen equilibrium of hemoglobin and myoglobin from the Pacific lugworm Abarenicola Pacifica

Abstract

The Pacific lugworm Abarenicola pacifica contains a high molecular weight extracellular vascular hemoglobin and a monomeric body wall myoglobin. 1. 2. The hemoglobin has an apparent molecular weight of 2.6 × 10 6 on Sepharose 4B chromatography and contains a submultiple of apparent mol. wt 235,000 from gel chromatography on Biogel A-1.5 M. The smallest subunit has a mol. wt 16,000 by sodium dodecyl sulfate gel electrophoresis, or 14,500 by Sephadex G-200 gel chromatography in the presence of 8 M urea and 0.1 M 2-mercaptoethanol. 2. 3. The myoglobin has a mol. wt 15–16,000 from gel chromatography and SDS gel electrophoresis and can be separated into seven components by disc gel electrophoresis. 3. 4. The amino acid composition of purified hemoglobin is reported. 4. 5. Iron analyses indicate one mole iron per 24,700 g hemoglobin, and one mole iron per 17,000 g myoglobin. 5. 6. The hemoglobin shows a pH-independent sigmoid oxygen equilibrium curve. The myoglobin displays a pH-independent hyperbolic oxygen equilibrium curve. The oxygen affinity of the myoglobin is higher than that of the hemoglobin. 6. 7. The hemoglobin and myoglobin of this polychaete are compared with those of other annelids.