title: Action spectra for the photoconsumption of oxygen by human ocular lipofuscin and lipofuscin extracts.
abstract: The action spectra for the photoconsumption of oxygen by lipofuscin isolated from human retinal pigment epithelium cells and liposomal suspensions containing extracts of lipofuscin are reported. The lipofuscin and lipofuscin extract action spectra are similar, demonstrating the phototoxic constituents of lipofuscin are present in the lipofuscin solvent extract. 2-[2,6-Dimethyl-8-(2,6,6-trimethyl-1-cyclohexen-1-yl)-1E,3E,5E,7E-octatetraenyl]-1-(2-hydroxyethyl)-4-[4-methyl-6-(2,6,6-trimethyl-1-cyclohexen-1-yl)-1E,3E,5E-hexatrienyl]-pyridinium (A2E), present in both intact granules and the solvent extract, has been invoked as an important contributor to the phototoxicity of lipofuscin. The action spectrum for oxygen photoconsumption by A2E follows its absorption spectrum but does not resemble the action spectrum for photoconsumption of oxygen by lipofuscin granules or lipofuscin extract. These results combined with recently reported experimental studies on the aerobic photoreactivity of A2E indicate that it is not a major contributor to the phototoxicity of lipofuscin.
authors.affiliation: Department of Biophysics, Jan Zurzycki Institute of Molecular Biology and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387 Krakow, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Pawlak
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Rózanowska
authors.forename: Mariusz
authors.initials: M
authors.lastname: Zareba
authors.forename: Laura E
authors.initials: LE
authors.lastname: Lamb
authors.forename: John D
authors.initials: JD
authors.lastname: Simon
authors.forename: Tadeusz
authors.initials: T
authors.lastname: Sarna
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002851:Chromatography, High Pressure Liquid; D006801:Humans; D008027:Light; D008062:Lipofuscin / Q000378:metabolism*; D008875:Middle Aged; D010100:Oxygen / Q000378:metabolism*; D010101:Oxygen Consumption; D012160:Retina / Q000166:cytology* / Q000378:metabolism; D013997:Time Factors
chemical_list: D008062:Lipofuscin; D010100:Oxygen