title: Kinetics of formation of deoxyribonucleic acid cross-links by 4'-(aminomethyl)-4,5',8-trimethylpsoralen.
abstract: If a mixture of T4 deoxyribonucleic acid (DNA) and 4'-(aminomethyl)-4,5',8-trimethylpsoralen is irradiated with two closely spaced pulses of long-wave UV laser light, the resulting cross-linking is dependent on the time delay between the pulses. As the delay lengthens to 1 mus, a rise in the number of cross-links is observed which follows first-order kinetics. This delay, the time required for most monoadducts to be able to absorb a second photon and thereupon form a cross-link, is interpreted in terms of a conformational change in the DNA at the psoralen intercalation site which may occur upon monoadduct formation.
mesh_terms: D055598:Chemical Phenomena; D002621:Chemistry; D003432:Cross-Linking Reagents; D004279:DNA, Viral / Q000528:radiation effects; D011564:Furocoumarins; D007700:Kinetics; D007834:Lasers; D009690:Nucleic Acid Conformation; D013604:T-Phages; D013997:Time Factors; D014307:Trioxsalen / Q000031:analogs & derivatives; D014466:Ultraviolet Rays
chemical_list: D003432:Cross-Linking Reagents; D004279:DNA, Viral; D011564:Furocoumarins; C018822:aminomethyltrioxsalen; D014307:Trioxsalen