Enzymatic elimination of hydrogen peroxide by a methemoglobin/L-tyrosine system

Tomoyasu Atoji, Hirotaka Yatami, Motonari Aihara, Shinji Takeoka*


研究成果: Article査読

2 被引用数 (Scopus)


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月

ASJC Scopus subject areas

  • バイオテクノロジー
  • 生体医工学


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