Pulse-radiolysis Studies of 8-methoxypsoralen

Summary

Both e_aq⁻ and ·OH have been found to react with 8-methoxypsoralen (8-MOP), giving rate-constants of 1·1 × 10¹⁰M⁻¹s⁻¹. Transient spectra of products from the reactions of e_aq⁻, ·OH and ·H with 8-MOP have been characterized. Rate-constants for the oxidation by 8-MOP of reduced and oxidized DNA bases have also been measured and found to lie in the range 3–6 × 10⁹M⁻¹s⁻¹. Oxidation of reduced bases occurs by electron transfer with 100 per cent efficiency in all cases. However, for oxidized bases, only ∼25 per cent of the intermediate yield produced by OH attack undergoes electron transfer; the balance of the oxidized base appears to form adducts with 8-MOP.