title: Oxygenation and EPR spectral properties of Aplysia myoglobins containing cobaltous porphyrins.
abstract: Cobalt myoglobins (Aplysia) have been reconstituted from apo-myoglobin (Aplysia) and proto-, meso-, and deutero-cobalt porphyrins. Each of them showed the 30--60 times lower oxygen affinity than those of the corresponding cobalt myoglobins (Sperm whale). Kinetic investigation of their oxygenation by the temperature-junp relaxation technique showed that the low oxygen affinity of cobalt myoglobin (Aplysia) is due to a large dissociation rate constant. the electron paramagnetic resonance (EPR) spectrum of oxy cobalt myoglobin (Aplysia) is affected by the replacement of H2O with D2O, suggesting a possible interaction between the bound oxygen and the neighboring hydrogen atom. A low temperature photodissociation study showed that the product of photolysis of oxy cobalt myoglobin (Aplysia) gives an EPR spectrum different from that of the deoxy-cobalt myoglobin (Aplysia) and from that of the photolysed form of oxy-cobalt myogloin (Sperm whale). These observations suggest that in oxy-cobalt myoglobin (Aplysia) the bound oxygen might interact with amino acid adjacent to it, but the interaction is weaker than that in oxy cobalt myoglobin (Sperm whale).
mesh_terms: D000818:Animals; D001048:Aplysia; D002248:Carbon Monoxide; D003035:Cobalt; D004578:Electron Spin Resonance Spectroscopy; D007700:Kinetics; D009211:Myoglobin / Q000378:metabolism; D010100:Oxygen; D011166:Porphyrins; D011485:Protein Binding; D014907:Whales
chemical_list: D009211:Myoglobin; D011166:Porphyrins; D003035:Cobalt; D002248:Carbon Monoxide; D010100:Oxygen