Interactions between N-aspartyl chlorin e6, detergent micelles and plasma lipoproteins.
Addition of plasma to the photosensitizing agent N-aspartyl chlorin e6 (NPe6) in Triton X-100 micelles results in a blue-shift of fluorescence emission, corresponding to a change in the average environmental dielectric constant from 8 to 32. This effect was not observed with anionic or cationic detergents or with several other sensitizers including a close analog, chlorin e6. The apolipoprotein fraction of high-density lipoproteins (HDL) was found responsible for this blue-shift. These results indicate a highly selective interaction between HDL apolipoproteins and NPe6 molecules. Addition of the HDL apolipoprotein to NPe6 incorporated into Triton micelles decreased the fraction of NPe6 molecules accessible to Cd(2+)-induced fluorescence quenching but resulted in an increase in the Stern-Volmer quenching constant (an index of quenching efficiency).
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Department of Pharmacology, Wayne State University School of Medicine, Detroit, MI 48201, USA.
D000970:Antineoplastic Agents / Q000737:chemistry*; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D004347:Drug Interactions; D006801:Humans; D008074:Lipoproteins / Q000097:blood* / Q000737:chemistry*; D008823:Micelles; D017830:Octoxynol / Q000737:chemistry*; D017319:Photosensitizing Agents / Q000737:chemistry*; D011166:Porphyrins / Q000097:blood / Q000737:chemistry*; D013050:Spectrometry, Fluorescence / Q000379:methods
D000970:Antineoplastic Agents; D008074:Lipoproteins; D008823:Micelles; D017319:Photosensitizing Agents; D011166:Porphyrins; D017830:Octoxynol; C053434:Talaporfin