Chiroptical and physicochemical properties of heme proteins from marine invertebrates

The respiratory proteins of many marine invertebrates are hemoglobins and myoglobins which have as their prosthetic group iron protoporphyrin IX. The hemoglobin from two species of the animal phylum Annelida and a species of the closely related phylum Echiura have been studied. Five major components of the monomeric hemoglobin from the polychaete annelid Glycera dibranchiata have been separated and characterized by absorption spectroscopy, isoelectric focusing, azide binding affinities and nitrosyl autoreduction kinetics. Similar studies have been performed on the hemoglobin from the annelid Cirriformia tentaculata and on the hemoglobin and myoglobin from the Echiuran Urechis caupo. Kinetic studies detailing the carbon monoxide driven reduction of Fe(III) proteins ere discussed in terms of distal pocket environment. In addition, oxygen binding kinetics of the hemoglobin from U. caupo are reported. Circular dichroism studies of native hemoglobins and myoglobins along with the respective apoproteins reconstituted with a synthetic symmetric porphyrin suggest that the sign and magnitude of the Soret c.d. signal are a function of both the heme orientation end surrounding globin environment.Ph.D., Chemistry -- Drexel University, 199