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Photoprocesses of Xanthene Dyes Bound to Lysozyme or Serum Albumin
Author(s) -
Zhang Yazhou,
Görner Helmut
Publication year - 2009
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.2008.00487.x
Subject(s) - xanthene , lysozyme , chemistry , albumin , serum albumin , biochemistry , photochemistry
The ground and excited state processes of eosin, erythrosin and rose bengal in aqueous solution were studied in the presence of lysozyme or bovine serum albumin (BSA). Noncovalent protein‐dye binding was analyzed by circular dichroism (CD), fluorescence and UV–Vis absorption spectroscopy. The effects of protein concentrations and pH were studied. Fluorescence quenching of the dye takes place due to binding to lysozyme and fluorescence enhancement due to low loading to BSA. The effects of proteins on the xanthene triplet state and its precursor were observed by time‐resolved 530 nm photolysis. The triplet lifetime is quenched by lysozyme and prolonged by loading to BSA. Light‐induced damages on both the dyes and proteins were observed under exclusion of oxygen. Photo‐oxidation is efficient for lysozyme and lower for BSA. The CD signal of the eosin/BSA system is maximum at pH 4, where the photo‐oxidation is minor.