Protoporphyrin IX catalyzed hydrogen peroxide to generate singlet oxygen

International Journal of Clinical and Experimental Medicine

Jun Zeng¹  Jihui Su¹  Jihui Han¹  Qiyin Sun¹  Quanshi Zhang¹  Yuehui Jin¹ 

关键词: Protoporphyrin;    singlet oxygen;    catalysis;   

DOI  :  

学科分类：医学（综合）

来源: e-Century Publishing Corporation

【 摘 要 】

Aim: To study the role of protoporphyrin IX (pPIX) in mitochondrial metabolism of hydrogen peroxide (H₂O₂). Methods: O₂^- specific fluorescent markers DMA (9,10-dimerthylanthracence) and SOSG (Singlet Oxygen Sensor Green reagent) were used for measurement of singlet oxygen (¹O₂). Catalyzing conversion of H₂O₂ into ¹O₂ by pPIX was monitored in vitro under varied H₂O₂ content, temperature, and PH value in the reaction. Ex vivo mitochondrial model was used to analyze effects of ferrochelatase (FECH) and high energy X-rays on this catalytic reaction. Results: In complete dark, measurable ¹O₂ was generated when 1.5 mM of H₂O₂ was incubated with 24 μM of pPIX H₂O₂ at 37°C for 3 hours. Mitochondrial yield of H₂O₂ was 0.11±0.03 nmole/mg/min. Mitochondrial FECH significantly improve the catalytic ability of pPIX converting H₂O₂ into ¹O₂. At presence of high-energy X-ray, incubation of 14.4 μM of pPIX with 0.54 μM of H₂O₂ also generated ¹O₂, during which the fluorescence density of 1.05 μM of DMA decreased by 41.5% (P < 0.05). This conversion was not observed when pPIX was replaced with structurally similar hematoporphyrin. Conclusion: pPIX can catalyze conversion of H₂O₂ into ¹O₂.

【 授权许可】

Unknown