Absorption spectrum and magnetic circular dichroism of heme-containing proteins in nonequilibrium states. I. Hemoglobin and its derivatives
Magonov, S.N.; Davydov, R.M.; Bliumenfel'd, L.A.; Vilu, R.O.; Arutiunian, A.M.
Molekuliarnaia Biologiia 12(4): 947-957
1978
ISSN/ISBN: 0026-8984 PMID: 683198 Document Number: 135409
Absorption and magnetic circular dichroism spectra of nonequilibrium states of hemoglobin and its derivatives formed by reduction oxidased forms of hemoproteins by thermalysed electrons at 77 degrees K were studied. Mixtures of low spin and high spin ferroforms were observed for nonequilibrium hemoglobin and its complexes with inosithexaphosphate and fluorine. The content of the high spin form increasing as follows: hemoglobin, complex with inosithexaphosphate, complex with fluorine. Only low spin forms were found for cyanide and azide complexes of hemoglobin reduced at low temperature. The spectral differences of nonequilibrium low spin ferroforms were supposed to be due to the presence of different ligands in the coordination sphere of the heme iron. The alpha-band splitting was observed for the nonequilibrium imidazole complex of hemoglobin. This effect was explained by a lowe-ring of the active centre's symmetry. The temperature relaxation of all nonequilibrium systems was investigated.