Quantitation of hydrogen peroxide formed during UV-visible irradiation of protoporphyrin, coproporphyrin and uroporphyrin
| Autor: | Herbert F. Haberman, I. Aravind Menon, Mary Ann C. Becker, Suruj D. Persad |
|---|---|
| Rok vydání: | 1990 |
| Předmět: |
Azides
Coproporphyrins Porphyrins Light Photochemistry Ultraviolet Rays Clinical Biochemistry Protoporphyrins Biochemistry Ehrlich ascites carcinoma chemistry.chemical_compound Photosensitivity Photosensitizer Uroporphyrins Hydrogen peroxide Sodium Azide Singlet oxygen Superoxide Dismutase Biochemistry (medical) General Medicine Hydrogen Peroxide Porphyrin chemistry Sodium azide Protoporphyrin |
| Zdroj: | Clinica chimica acta; international journal of clinical chemistry. 186(3) |
| ISSN: | 0009-8981 |
| Popis: | Free porphyrins are strong photosensitizers. Previously reported findings indicate that the in vitro cell lysis induced by irradiation in the presence of coproporphyrin (CP) and uroporphyrin (UP) is mediated by H 2 O 2 and that induced by irradiation with protoporphyrin (PP) is not mediated by H 2 O 2 . In the present study the possible role of H 2 O 2 in the porphyrin photosensitization was investigated by direct measurement of the H 2 O 2 formed during the irradiation of PP, CP and UP. Our results show that the amount of H 2 O 2 formed decreased in the following order: UP, CP, PP. The amounts of H 2 O 2 formed during irradiation of CP and PP were approximately 86% and 38% respectively in comparison to the H 2 O 2 formed during the irradiation of UP. The formation of H 2 O 2 was inhibited by sodium azide, a strong quencher of singlet oxygen. These observations are in good agreement with the previous report that the in vitro photolysis of Ehrlich ascites carcinoma cells by UP and CP, but not that by PP, was inhibited by catalase and clinical findings with patients with erythropoetic protoporphyria (EPP) and porphyria cutanea tarda (PCT). The patients with EPP, where the photosensitivity is due to PP, respond well to β-carotene while β-carotene does not protect against the photosensitivity in PCT, in which case the photosensitivity is due to uroporphyrin. |
| Databáze: | OpenAIRE |
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