Premium
Saccharomyces cerevisiae Mutants Defective in Heme Biosynthesis as a Tool for Studying the Mechanism of Phototoxicity of Porphyrins
Author(s) -
Otdek Teresa,
Nhi Nguyen Bich,
Rytka Joanna
Publication year - 1996
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1996.tb01861.x
Subject(s) - phototoxicity , erythropoietic protoporphyria , protoporphyrin , chemistry , heme , catalase , porphyria , biochemistry , protoporphyrin ix , saccharomyces cerevisiae , superoxide dismutase , photosensitizer , mechanism of action , photosensitivity , uroporphyrinogen iii decarboxylase , porphyria cutanea tarda , yeast , porphyrin , photochemistry , in vitro , enzyme , biology , photodynamic therapy , physics , organic chemistry , quantum mechanics , endocrinology
— Mutants of Saccharomyces cerevisiae accumulating uroporphyrin (UP) or protoporphyrin (PP) were used as a model for the in vivo phototoxic effect of porphyrins observed in the human skin photosensitivity associated with porphyrias (porphyria cutanea tarda and erythropoietic protoporphyria). We have found that UP is localized in vacuoles and PP is present in all compartments except vacuoles in yeast cells. Endogenous PP is much more effective as a photosensitizer of yeast cells than UP. Protoporphyrin action is strictly dependent on the presence of oxygen. In contrast, UP displays a phototoxic effect even if oxygen is not present in the suspension, implicating a free radical mechanism that operates in anaero‐biosis upon photosensitization by UP. Catalase or superoxide dismutase deficiency affects photosensitization by UP. A possible mechanism of UP photosensitizing activity is discussed.