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This work is a study of the radioinduced transformations undergone by intraglobular hemoglobin. Mössbauer spectrometry allows us to study in a wide range of doses the effect of X rays on deoxyhemoglobin as well as on oxyhemoglobin. Using this technique we have shown large differences between these two derivatives of hemoglobin. Deoxyhemoglobin leads to the formation of only one ferric nonheme compound while oxyhemoglobin produces this same compound as a last step after intermediary production of deoxyhemoglobin, methemoglobin, hemichromes, and hemochromes. We have also found that heat incubation and X rays have a similar effect on HbO2 except for the dissociation, which is absent in heat incubation. We have found a value for the energy needed for such a radiodissociation of HbO2 similar to that given by other authors utilizing other methods. Finally, we propose some explanations for the formation of the different compounds involved based on structural considerations.

Résumé. -L'étude des modifications en fonction de la dose du spectre Môssbauer de globules rouges artériels irradiés aux rayons X montre que l'irradiation de Foxyhémoglobine globulaire entraîne la production d'une forme déoxy ligandfree probablement quickly reacting comme dans le cas, bien connu, de la photodissociation ainsi que d'une hémoglobine ferrique high spin. Pour des doses de radiation croissantes, Thème de ces radioproduits est détruit et un composé final du type ferrique high spin à environnement rhomboédrique est produit. Ces résultats sont obtenus par comparaison avec les spectres RPE.La spectrométrie Môssbauer montre que les mêmes composés sont produits sous l'action de la chaleur, à l'exlcusion de la forme déoxy ligandfree.Abstract. -The study of variations in the Mossbauer spectrum of X-irradiated arterial red cells as a function of dose shows that irradiation of red cells oxyhemoglobin leads to the production of a ligand free deoxy form, probably fast-reacting as in the well-known case of photodissociation, and of a high spin ferric hemoglobin. For increasing radiation doses the heme of these radioproducts is destroyed and a final compound of the type high spin ferric in rhombic environment is produced. These results are obtained by comparison with EPR spectra.Mossbauer spectrometry shows that these same compounds, excluding the «ligand free » deoxy form, are formed by the action of heat.