ADENOSINE-MEDIATED PHOTOREACTION OF 4,5',8-TRIMETHYLPSORALEN WITH ALCOHOLS

Irradiation of thin films consisting of 4,5',8-trimethytpsoralen (TMP) , adenosine and small amounts of alcohols led to TMP-alcohol photoaddu cts in addition to TMP-adenosine photoadducts. Four TMP-ethanol and tw o TMP-methanol adducts have been separated and characterized. Covalent bonds were formed between the 4-carbon of TMP and the alpha-carbon to the hydroxy group in the alcohols. The TMP-alcohol photoadducts were for-med only in the TMP film containing small amounts of alcohol and a denosine. Furthermore, no photoadduct of TMP and ribose was detected u pon phototysis of a TMP-ribose film, suggesting that the adenine moiet y plays a specific role in the reaction. The interaction of adenosine with psoralens in a dry film may be related to the DNA sequence select ivity observed for the photoreaction of psoralens with DNA.