PSORALEN PROTEIN PHOTOCHEMISTRY - A FORGOTTEN FIELD

8-Methoxypsoralen in combination with long wavelength ultraviolet ligh t is employed for the treatment of several cutaneous disorders, such a s psoriasis, vitiligo and mycosis fungoides. It is common to attribute the efficacy of the photochemotherapy to the formation of psoralen DN A photoadducts. Thus, the main research effort has been directed towar ds the elucidation of nucleic acid photochemistry and related subseque nt events (mutagenicity, toxicity). However, psoralens have been shown to undergo photoaddition reactions with other cellular components. In this review the status of psoralen-DNA photobiology is briefly summar ized. The main focus, however, is on a survey of psoralen photochemica l modification of proteins and the ways by which these additional phot obiological events can impact the antigenicity and potentially immunog enicity of treated cells. Some preliminary results show the extent of psoralen-amino acid photoadduct formation and their impact on enzymati c processing.