Protoporphyrin IX (Pp IX) is the main photosensitizer in photochemotherapy with 5-aminolevulinic acid (ALA). Pp IX is photolabile and the present work shows that 70-95% of Pp IX in cells is degraded by clinically relevant light exposures (40-200 J cm 22 at 630 nm). During light exposure a small yiel
Formation of water-soluble porphyrins and protoporphyrin IX in 5-aminolevulinic-acid-incubated carcinoma cells
β Scribed by W. Dietel; K. Bolsen; E. Dickson; C. Fritsch; R. Pottier; R. Wendenburg
- Publisher
- Elsevier Science
- Year
- 1996
- Tongue
- English
- Weight
- 601 KB
- Volume
- 33
- Category
- Article
- ISSN
- 1011-1344
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β¦ Synopsis
The bioconversion of 5-aminolevulinic acid (ALA) into hydrophobic protoporphyrin IX and other water-soluble porphyrins was investigated in Ehrlich ascite carcinoma (EAC) cells and in a myeloma cell line. The effects of irradiation (514 nm), temperature, incubation time and added glucose on the relative porphyrin concentrations (protoporphyrin vs. water-soluble porphyrins) were examined. Variations in these parameters induced a change in the amount of water-soluble porphyrins relative to protoporphyrin IX. The main component of the hydrophilic porphyrins was found to be uroporphyrin (Up), with minor components of coproporphyrin (Cp) and other carboxyporphyrins. The enhanced production of water-soluble porphyrins appears to be associated with alterations in the activities of the various enzymes in the heme biosynthetic pathway, resulting, for example, in the reduction in the activity of mitochondrial enzymes.
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