Tohoku J. Exp. Med., 2004, 203(4)

Metabolism of Pyrogallol to Purpurogallin by Human Erythrocytic Hemoglobin

KAORI MIYAZAKI, SADAO ARAI,¹ TOSHIHIKO IWAMOTO, MASARU TAKASAKI and AKIO TOMODA²

Department of Geriatric Medicine, Tokyo Medical University, Tokyo 160-0032, ¹Department of Chemistry, and ²Department of Biochemistry and Intractable Immune System Disease Research Center, Tokyo Medical University, Tokyo 160-0022

The aim of this study was to investigate the oxido-reductive reactions of human hemoglobin with pyrogallol and the metabolism of pyrogallol by the protein, which contains a protoporphyrin IX like cytochrome P-450. Pyrogallol, having three hydroxy groups at the adjacent positions in the benzene ring, oxidized human oxyhemoglobin to methemoglobin and reduced human methemoglobin to oxyhemoglobin. Since superoxide dismutase and catalase inhibited these reactions extensively, active oxygens such as superoxide and hydrogen peroxide were considered to be involved in the oxido-reductive reaction of human hemoglobin by pyrogallol. It was also found that the metabolism of pyrogallol to purpurogallin occurred quickly in human erythrocytes, i.e., when pyrogallol was added to human erythrocyte suspension, it oxidized intracellular hemoglobin and produced purpurogallin. The metabolism of pyrogallol to purpurogallin was explained by the pyrogallol oxidation with superoxide and hydrogen peroxide produced during the oxido-reductive reactions of human hemoglobin with pyrogallol. The present results show that human erythrocytes can metabolize pyrogallol, suggesting that the cells may be involved in the metabolism of some drugs in the human body.

keywords —— erythrocytes; hemoglobin; pyrogallol; purpurogallin

© 2004 Tohoku University Medical Press

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Address for reprints: Akio Tomoda, M.D., Ph.D., Department of Biochemistry and Intractable Immune System Disease Research Center, Tokyo Medical University, Tokyo 160-0022, Japan.

e-mail: tomoda@tokyo-med.ac.jp