Comparative Study of Oxyhemoglobin Radiolysis and Thermolysis by Mössbauer Spectroscopy

Abstract

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.

Mössbauer spectroscopy in biomedical research

“…It should be noted that earlier study of oxyhemoglobin in red blood cells exposed to X-rays by Mo ¨ssbauer spectroscopy showed oxyhemoglobin deoxygenation while protein destruction led to formation of two species: a hemochrome-like compound and a non-heme Fe(III) compound that was considered as a final product of protein destruction. 48,49 Mo ¨ssbauer spectra of oxyhemoglobin exposed to microwave heating (2.45 GHz, 900 W) for 5 and 15 s demonstrated an increase of oxyhemoglobin spectral line width and the formation of a ferric compound. 46 Mo ¨ssbauer parameters of oxyhemoglobin subspectra revealed almost the same values of DE Q and d as those for a non-irradiated oxyhemoglobin sample.…”

Mössbauer spectroscopy: Application in biomedical research

“…Mössbauer spectroscopy can be used to investigate some molecular mechanisms of biological effects of exogenous agents. The study of deoxy-and oxyhemoglobin irradiated by X-rays identified iron containing compounds resulting from radiolysis of proteins and showed differences of both hemoglobin forms destruction [52,53]. Another study of oxyhemoglobin radiolysis demonstrated the formation of different products of protein damage by γ-rays of various energies, by electrons and by microwave heating [54][55][56][57][58].…”