12 September 2002 Chemiluminescence from human serum albumin oxidation by singlet oxygen
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Irradiating the mixture of 5 ?M human serum albumin (HSA) with 10?M hematoporphyrin (HP) in 0.01 M phosphate buffered saline (PBS, pH 7.2) solution with visible light resulted in a peak chemiluminescence (CL) followed by rapid decay, which could be detected by a highly sensitive intensified charge coupled device (ICCD). The CL decays almost double-exponentially with a lifetime of about I 80 s. Experiments of bubbling air indicate that resolved oxygen molecules play a critical role to the CL, and the CL intensity depends on concentrations ofHP and HSA in PBS solution. The substitution of D20 for H20 increased the CL intensity and the CL intensity was reduced at the addition of the singlet oxygen (102) quencher of4O mM sodium azide (NaN3). Fluorescence-quenching experiments ofHSA at 330 nm during a 40-mm irradiation show aromatic amino acids such as tryptophan (Trp) were destroyed along with the decrease of CL intensity during the course of photosensitization of HP. These results suggest that 102 formation from the photosensitization of HP results in the oxidation of aromatic amino acids in HSA and the CL is a result of the decay to ground level ofexcited species generated from the oxidation ofaromatic amino acids.
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Juan Wang, Juan Wang, Da Xing, Da Xing, Xuejin Hu, Xuejin Hu, "Chemiluminescence from human serum albumin oxidation by singlet oxygen", Proc. SPIE 4916, Optics in Health Care and Biomedical Optics: Diagnostics and Treatment, (12 September 2002); doi: 10.1117/12.482965; https://doi.org/10.1117/12.482965

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