We studied the peroxidase activity of ferrylhemoglobin radical (Hb(Fe4+ = O*)) generated by the reaction of metHb (Hb(Fe3+)) with hydrogen peroxide (H2O2). To clarify the behaviors of ferrylHb radical, it was isolated from the reaction mixture of metHb and H2O2 by GPC at 4°C. The radical species underwent rapid autoreduction to metHb at 37°C accompanied with denaturation; however, it was stable for several minutes at 4°C. In ESR measurements, the signal of the ferrylHb radical immediately disappeared in the presence of l-Tyrosine (l-Tyr), and simultaneously, the signal of the ferric heme increased. This suggested that the ferrylHb radical immediately converted to metHb by l-Tyr even at 4°C. Furthermore, dimerized l-Tyr was detected in the reaction mixture. This showed that the ferrylHb radical was reduced to metHb by electron donation from l-Tyr. The enzymatic reaction using l-Tyr as the substrate resulted in the elimination of H2O2 in this system.
|ジャーナル||Artificial Cells, Blood Substitutes, and Biotechnology|
|出版ステータス||Published - 2007 11|
ASJC Scopus subject areas
- Biomedical Engineering