title: Chemical structure of 3-carbethoxypsoralen-DNA photoadducts.
abstract: The enzymatic digest from salmon sperm DNA photochemically modified by the monofunctional 3-carbethoxypsoralen was analyzed by high-performance liquid chromatography. The modified nucleosides extracted from DNA were compared with model compounds obtained from irradiation in the dry state of mixtures of 3-carbethoxypsoralen with 2'-deoxyribonucleosides whose chemical structures had previously been characterized. The main photoadducts formed in DNA are two cis-syn diastereoisomers formed via a C4-cycloaddition reaction involving the 4', 5' double bond of 3-carbethoxypsoralen and the 5,6 double bond of 2'-deoxythymidine. Among them, the most polar one accounts for 72%. Under the same conditions, photoadducts formed between 3-carbethoxypsoralen and 2'deoxycytidine account for less than 1%.
mesh_terms: D055598:Chemical Phenomena; D002621:Chemistry; D002851:Chromatography, High Pressure Liquid; D004247:DNA / Q000528:radiation effects*; D003841:Deoxycytidine; D003857:Deoxyuridine; D011564:Furocoumarins; D008027:Light; D010777:Photochemistry; D013050:Spectrometry, Fluorescence; D013237:Stereoisomerism; D013936:Thymidine
chemical_list: D011564:Furocoumarins; D003841:Deoxycytidine; D004247:DNA; C017104:3-carbethoxypsoralen; D013936:Thymidine; D003857:Deoxyuridine