In Vitro Studies on Longwave Ultraviolet Light-Dependent Reactions of the Skin Photosensitizer Chlorpromazine with Nucleic Acids, Purines and Pyrimidines

Abstract

Fluorescence spectral shifts were observed when chlorpromazine was irradiated with long-wave ultraviolet light in the presence of nucleic acids. An increase in fluorescence was accompanied by incorporation of radioactivity from 3 H-chlorpromazine into the alcohol-insoluble (nucleic acid) fraction of reaction mixtures. Apparent complex formation proceeded at a faster rate with single-stranded nucleic acids than with double-stranded nucleic acids. Spectral shifts also occurred when chlorpromazine was irradiated with thymine, cytosine, uracil, or adenine.