title: Accumulation and interaction of hypericin in low-density lipoprotein--a photophysical study.
abstract: The accumulation and interaction of hypericin with the biologically important macromolecule, low-density lipoprotein (LDL), is investigated using various steady-state and time-resolved fluorescence measurements. It is concluded that multiple hypericins can penetrate considerably deeply into the LDL molecule. Up to approximately 20 nonaggregated hypericin molecules can enter LDL; but upon increasing the hypericin concentration, the fluorescence lifetime of hypericin decreases drastically, suggesting most likely the self-quenching of aggregated hypericin. There is also evidence of energy transfer from tryptophans of the constituent protein, apoB-100, to hypericin in LDL. The results demonstrate the ability of LDL to solubilize hypericin (a known photosensitizer) in nonaggregated form, which has implications for the construction of drug delivery systems.
authors.affiliation: Department of Chemistry, Iowa State University, Ames, IA, USA.
authors.forename: Prasun
authors.initials: P
authors.lastname: Mukherjee
authors.forename: Ramkrishna
authors.initials: R
authors.lastname: Adhikary
authors.forename: Mintu
authors.initials: M
authors.lastname: Halder
authors.forename: Jacob W
authors.initials: JW
authors.lastname: Petrich
authors.forename: Pavol
authors.initials: P
authors.lastname: Miskovsky
mesh_terms: D000873:Anthracenes; D005453:Fluorescence; D008077:Lipoproteins, LDL / Q000737:chemistry*; D015394:Molecular Structure; D010569:Perylene / Q000031:analogs & derivatives* / Q000737:chemistry; D017319:Photosensitizing Agents / Q000737:chemistry*; D012995:Solubility; D013050:Spectrometry, Fluorescence; D013997:Time Factors; D014364:Tryptophan / Q000737:chemistry
chemical_list: D000873:Anthracenes; D008077:Lipoproteins, LDL; D017319:Photosensitizing Agents; D010569:Perylene; C004965:hypericin; D014364:Tryptophan