Degree of dissociation of apohemoglobin studied by nanosecond fluorescence-polarization technique

Kazuhiko Kinosita*, Shigeki Mitaku, Akira Ikegami

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


A fluorescent dye 1-anilino-8-naphthalene sulfonate was complexed with human apohemoglobin and sperm whale apomyoglobin. Nanosecond fluorescencepolarization kinetics were measured for each of these complexes in KCl solutions to obtain their fluorescence lifetimes and rotational correlation times. The rotational correlation time of apohemoglobin-dye complex was found to be 21 ns, which was about twice that of apomyoglobin-dye complex, 11 ns. These values were constant over an ionic strength range from 0 to 1.7. Circular dichroism spectra (215-300 nm) and fluorescence lifetimes of the complexes were also found to be independent of the ionic strength, indicating that no gross conformational change occurs with the change in the salt concentration. These results suggest that apohemoglobin remains dimeric over the ionic-strength range examined.

Original languageEnglish
Pages (from-to)10-14
Number of pages5
JournalBBA - Protein Structure
Issue number1
Publication statusPublished - 1975 May 30
Externally publishedYes

ASJC Scopus subject areas

  • Medicine(all)


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