Fluorescence spectroscopic study of hypericin-photosensitized oxidation of low-density lipoproteins.
By means of UV-VIS absorption and fluorescence spectroscopy, we demonstrate that the photosensitizer hypericin (Hyp) interacts nonspecifically with low-density lipoproteins (LDL), most probably with the lipid fraction of LDL. The molar ratio of monomeric Hyp binding to nonoxidized LDL and mildly oxidized LDL is 30:1. Increasing the Hyp concentration further leads to the formation of Hyp aggregates inside the LDL molecule. We also demonstrate that photoactivated Hyp oxidizes LDL in a light dose and excitation wavelength dependent manner. The level of oxidation of LDL depends on the amount of Hyp inside the LDL molecule. The maximum of the photosensitized oxidation of the LDL by Hyp is achieved for a 30:1 molar ratio, which corresponds to the maximum concentration of monomeric form of Hyp in LDL.
Kascakova
Slavka
S
Department of Biophysics, University of P. J. Safarik, Kosice, Slovak Republic.
Refregiers
Matthieu
M
Jancura
Daniel
D
Sureau
Franck
F
Maurizot
Jean-Claude
JC
Miskovsky
Pavol
P
D000873:Anthracenes; D001665:Binding Sites; D004307:Dose-Response Relationship, Radiation; D008077:Lipoproteins, LDL / Q000737:chemistry* / Q000378:metabolism / Q000528:radiation effects*; D046911:Macromolecular Substances / Q000737:chemistry / Q000378:metabolism / Q000528:radiation effects; D015394:Molecular Structure; D010084:Oxidation-Reduction; D010569:Perylene / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism; D017319:Photosensitizing Agents / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet
D000873:Anthracenes; D008077:Lipoproteins, LDL; D046911:Macromolecular Substances; D017319:Photosensitizing Agents; D010569:Perylene; C004965:hypericin