TY - JOUR
T1 - Enzymatic elimination of hydrogen peroxide by a methemoglobin/L-tyrosine system
AU - Atoji, Tomoyasu
AU - Yatami, Hirotaka
AU - Aihara, Motonari
AU - Takeoka, Shinji
N1 - Funding Information:
Keywords: Ferrylhemoglobin radical; Hemoglobin vesicle; Hydrogen peroxide; L-Tyrosine; Methemoglobin; Peroxidase activity The authors thank Dr. T. Shibue at Material Characterization Center Laboratory of Waseda University for the technical advise and useful discussion about ESR measurement. This work was supported in part by a Health and Labor Science Research Grant from Ministry of Health, Labor and Welfare, Japan, a Research Grant from Ministry of Education, Science, Sports and Culture, Japan (MEXT, 18500368), and 21-COE ‘‘Practical Nano-Chemistry’’ from MEXT.
PY - 2007/11
Y1 - 2007/11
N2 - 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.
AB - 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.
KW - Ferrylhemoglobin radical
KW - Hemoglobin vesicle
KW - Hydrogen peroxide
KW - L-Tyrosine
KW - Methemoglobin
KW - Peroxidase activity
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U2 - 10.1080/10731190701730180
DO - 10.1080/10731190701730180
M3 - Article
C2 - 18097784
AN - SCOPUS:37549034690
SN - 1073-1199
VL - 35
SP - 555
EP - 567
JO - Artificial Cells, Blood Substitutes, and Biotechnology
JF - Artificial Cells, Blood Substitutes, and Biotechnology
IS - 6
ER -