Title of article :
Characterization of the photoproducts of protoporphyrin IX bound to human serum albumin and immunoglobulin G Original Research Article
Author/Authors :
Lorenzo Brancaleon، نويسنده , , Steven W. Magennis، نويسنده , , Ifor D.W. Samuel، نويسنده , , Ebinazar Namdas، نويسنده , , Andrea Lesar، نويسنده , , Harry Moseley، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2004
Pages :
10
From page :
351
To page :
360
Abstract :
Clinically useful photosensitisers (PSs) are likely bound to subcellular and molecular targets during phototherapy. Binding to a macromolecule has the potential to change the photophysical and photochemical characteristics of the PSs that are crucial for their phototoxicity and cell-killing activity. We investigated the effects of binding of a specific PS (protoporphyrin IX or PPIX) to two proteins, human serum albumin (HSA) and a commercially available immunoglobulin (IgG). These two proteins provide two different environments for PPIX. The albumin binds PPIX in hydrophobic binding sites located in subdomain IIA and IIIA, conversely IgG leaves PPIX exposed to the solvent. We show that photophysical parameters such as emission maxima and fluorescence lifetime depend on the binding site. Our results indicate that the different binding site yields very different rates of formation of photoproducts (more than three times higher for PPIX bound to HSA than to IgG) and that different mechanisms of formation may be occurring. Our characterization shows the relevance of protein binding for the photochemistry and ultimately the phototoxicity of PSs.
Keywords :
Human serum albumin , Protoporphyrin IX , Immunoglobulin G , Fluorescence spectroscopy
Journal title :
Biophysical Chemistry
Serial Year :
2004
Journal title :
Biophysical Chemistry
Record number :
1113466
Link To Document :
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