FUNCTIONAL PROPERTIES OF PARTIALLY OXIDIZED TROUT HEMOGLOBINS

Bruno Giardina, G Falcioni, G Fortuna, M Brunori, J. Wyman

Risultato della ricerca: Contributo in rivistaArticolo in rivista

9 Citazioni (Scopus)

Abstract

This paper reports on a study of the effect of partial oxidation on oxygen and carbon monoxide binding by components I and IV of trout hemoglobin. The O2 binding equilibria of the various oxidation mixtures show a decrease in the heme-heme interactions as the number of oxidized sites is increased. However the large Bohr effect, characteristic of Hb Trout IV, is maintained unchanged. Similarly the time course of CO combination changes on increasing the fractional oxidation, and the autocatalytic character of the CO binding kinetics is lost; however the pH dependence of the apparent “on” constant in the oxidation mixtures is similar to that characteristic of the native molecule. The results of the O2 equilibria and of CO binding kinetics may be interpreted in accordance with the two state concerted model suggesting that in the oxidation intermediates there is the fraction of the high affinity (R) conformation. Additional experiments on the effect of azide, and fluoride, ferric ligands which produce a change of spin state of the heme iron, suggest that additional second order conformational changes may also come into play
Lingua originaleEnglish
pagine (da-a)171-177
Numero di pagine7
RivistaBIOCHIMICA ET BIOPHYSICA ACTA
Volume490
DOI
Stato di pubblicazionePubblicato - 1977

Keywords

  • HEMOGLOBIN

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