부산대학교 도서관

In a study by electron paramagnetic resonance (EPR) at 163 K on blood serum from 14 patients with homozygous β-thalassemia receiving transfusional and chelating therapy, a previously unnoticed low spin (LS) ferriheme resonance was detected in 8 subjects. In 7 patients weak lines with g values of 2.24 ± 0.04 and 2.16 ± 0.02 were seen occasionally and evidenced individual variability, and in the 8th one the corresponding resonance was intense and located at g = 2.28. Around g ≈ 6 methemealbumin and, in addition, other high spin (HS) ferriheme proteins were seen. After a freeze-thaw cycle, all these resonances showed g value changes, but most remarkably the g = 2.28 line shifted to g = 2.17, suggesting changes in the heme environment. The g = 2.28 resonance could be attributed both to a 'pure' LS state and to LS-HS dynamic spin interconversion. The newly observed species were postulated to be various methemoglobin derivatives ('acid' and 'alkaline' MetHb, and different hemichromes) released from erythrocytes. Their relations with other spectroscopic and clinical parameters are discussed. The LS and HS resonances may give insight of possible medical relevance on the incomplete suppression of patient's own erythrocyte synthesis by transfusions, on the clinical condition severity and on the electrochemical state of blood in homozygous β-thalassemia. [ABSTRACT FROM AUTHOR]