Formation of a Nonaoxirane from A2E, a Lipofuscin Fluorophore related to Macular Degeneration, and Evidence of Singlet Oxygen Involvement This work was supported by NIH grant GM 34509 (K.N.), NSF grant NSF-CHE-98-12676 (N.J.T. and S.J.), and NIH grant EY-12951 (J.R.S.).
Nine epoxide rings are formed sequentially when A2E is irradiated with blue light in the presence of oxygen [Eq. (1)]. Mechanistically, A2E generates singlet oxygen and reacts with it to give the polyoxiranes. An understanding of the reaction of A2E with oxygen is important as blue light induces the apoptotic death of A2E-laden retinal pigment epithelium cells, which are typical of age-related macular degeneration.