Pattern of OH radical reaction with adenine and its nucleosides and nucleotides. Characterization of two types of isomeric OH adduct and their unimolecular transformation reactions

摘要: The {sup {sm bullet}}OH radical reacts in aqueous solution with adenine, 9-methyladenine, adenosine and its 3{prime}- 5{prime}-mono- 3{prime},5{prime}-diphosphates, the corresponding 2{prime}-deoxyadenosines by addition to C4 C8 of purine system. resulting hydroxycyclohexa- or penta(aza)dienyl-type radicals A4OH{sup bullet}} (formed at C4) A8OH{sup (by C8) undergo a dehydration ring-opening reaction, respectively, for which activation parameters pH dependencies have been determined. Dehydration bullet}}, yields an oxidizing N{sup 6}-centered neutral radical, is inhibited H{sup +}, whereas ring opening accelerated +} (and also OH{sup {minus}}). Product analysis data on adenine concerning effect additives yield depletion formation 8-hydroxyadenine indicate that repaired reduction derived from bullet}}.