DIAMINO ACID-DERIVATIVES OF PORPHYRINS PENETRATE INTO YEAST-CELLS, INDUCE PHOTODAMAGE, BUT HAVE NO MUTAGENIC EFFECT

The yeast Saccharomyces cerevisiae was used as a model eukaryotic orga nism to study the uptake of diamino acid derivatives of porphyrins and their phototoxicity with particular emphasis on possible mutagenic ef fects, The water-soluble hematoporphyrin derivatives diarginate (HpD[A rg](2)) and 1-arginin di(N-amino acid)-protoporphyrinate used in this study are effective photosensitizers in tumor photodynamic therapy, De pending on the amino acid substituent, the porphyrin derivatives diffe r in their affinity for yeast cells. It is shown that HpD(Arg)(2) and PP(Met)(2) (Arg)(2) penetrate into the yeast cell and are metabolized, Both compounds sensitize yeast cells to photodamage but have no mutag enic effect on nuclear or mitochondrial genomes.