Oxygenation and EPR spectral properties of Aplysia myoglobins containing cobaltous porphyrins

Masao Ikeda-Saito, Maurizio Brunori, Takashi Yonetani

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28 Citations (Scopus)


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-jump 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 photo-lysed form of oxy-cohalt 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).

Original languageEnglish
Pages (from-to)173-180
Number of pages8
JournalBBA - Protein Structure
Issue number1
Publication statusPublished - 1978 Mar 28

ASJC Scopus subject areas

  • Medicine(all)


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