Physiological production of singlet molecular oxygen in the myeloperoxidase‐H2O2‐chloride system

FEBS Letters

Kakinuma, Katsuko¹  Miyazaki, Junji¹  Fujinaga, Toru²  Kiryu, Chika¹  Makiuchi, Masao¹ 

[1] Biophotonics Information Laboratories, Yamagata Advanced Technology Research Center, Matsuei 2-2-1, Yamagata 990-2473, Japan;Department of Veterinary Clinical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, N-18, W-9, Kita-ku, Sapporo 060-0818, Japan

关键词: Singlet oxygen;    Myeloperoxidase;    Near infrared light emission;    1O2;    singlet oxygen;    1ΔgO2;    delta singlet oxygen;    3Σg −O2;    triplet oxygen;    MPO;    myeloperoxidase;    EPO;    eosinophil peroxidase;   

DOI  :  10.1016/S0014-5793(98)01700-1

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The putative role of singlet oxygen (¹O₂) in the respiratory burst of neutrophils has remained elusive due to the lack of reliable means to study its quantitative production. To measure ¹O₂ directly from biological or chemical reactions in the near infrared region, we have developed a highly sensitive detection system which employs two InGaAs/InP pin photodiodes incorporated with a dual charge integrating amplifier circuit. Using this detection system, we detected light emission derived from a myeloperoxidase (MPO)-mediated reaction in physiological conditions: pH 7.4, 1–30 nM MPO, 10–100 μM H₂O₂ and 100–130 mM Cl⁻ in place of Br⁻ without the use of deuterium oxide. The MPO-H₂O₂-Cl⁻ system exhibited a single emission peak at 1.27 μm with a spectral distribution identical to that of delta singlet oxygen. Our results suggest physiological production of ¹O₂ in the MPO-H₂O₂-Cl⁻ system at an intravacuolar neutral pH. The MPO-mediated generation of ¹O₂, which may have an important role in host defense mechanisms, is discussed in connection with previous results.

【 授权许可】

Unknown