Non-enzymatic, tetrahydrobiopterin-mediated hydroxylation of phenylalanine

Abstract

Product yields are reported for the tetrahydrobiopterin-mediated, non-enzymatic hydroxylation of phenylalanine under a variety of conditions, and compared with reactions involving Fenton's reagent. Hydroxyl radicals are shown to be partially involved, whilst the hydroperoxyl radical appears to be unreactive towards hydroxylation. A low N.I.H. shift indicates the reactive entity to be free radical in nature, and the involvement of iron(II)–oxygen complexes is considered.