| Abstract: | To examine the effects of a replacement of the proximal or the distal histidine on the structure of hemoglobin (Hb), absorption and circular dichroic (CD) spectra of five species of Hbs M in the visible region were measured. Four Hbs M had a characteristic but a similar absorption spectrum upon amino acid substitution, however, the proximal histidine replaced Hbs M (Hb M Iwate and Hb M Hyde Park) showed considerably different CD spectra from those of the distal histidine replaced ones (Hb M Boston and Hb M Saskatoon). The former exhibited large positive CD but the latter gave a complex CD spectrum with positive and negative extrema. On the other hand, absorption and CD spectra of Hb M Milwaukee did not changed very much from those of Hb A. |
