Chemiluminescence from Human Serum Albumin Oxidation by Singlet Oxygen by Singlet Oxygen

許多生物反應過程都伴隨有微弱的光子輻射，通過對生物組織及生物體弱發光的探測和成像可以方便地檢測生物的各種變化。本文的研究中，用可見光輻照存在於0.01M的磷酸緩衝液(PBS, pH7.2)中的5μM的人血清白蛋白(HSA)與10μM的血卟啉(HP)混合液，關閉激發光後，用一高靈敏的增強型CCD(ICCD)可以探測到混合液發出一峰值化學發光，此化學發光隨時間迅速呈雙指數衰減，壽命大約為180秒。沖器實驗發現，溶解氧對這種化學發光有很關鍵的作用。實驗還發現，這種化學發光的強度和PBS溶液中HP及HAS的濃度有關係，實驗中用重水(D2O)取代水(H2O)可增強化學發光的強度。輻照混合液40分鐘過程中，HAS在330nm處的發光淬火實驗表明HP的光敏化反應過程中色氨酸(Trp)等芳香族氨基酸隨著化學發光強度的降低被破壞。這些實驗結果表明，HP光敏化反應產生的單重態氧導致了人血清白蛋白中芳香族氨基酸的氧化，實驗探測到的化學發光正是芳香族氨基酸氧化過程中產生的激發態產物返回激發態發出的光子。

關鍵字

人血清白蛋白；血卟啉單重態氧；化學發光；光敏化

並列摘要

Irradiating the mixture of 5μM human serum albumin (HSA) with 10μM heatoporphyrin (HP) in 0.01M 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 (ICCO). The CL decays almost double-exponentially with a lifetime of about 180 s. Experiments of bubbling air indicate that resolved oxygen molecules play a critical role to the CL, and the CL intensity depends on concentrations of HP and HSA in PBS solution. The substitution of D2O for H2O increased the CL intensity and the CL intensity was reduced at the addition of the singlet oxygen (1O2) quencher of 40 mM sodium azide (NaN3). Fluorescence-quenching experiments of HSA at 330 nm during a 40-min 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 1O2 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 of excited species generated from the oxidation of aromatic amino acids.

並列關鍵字

human serum albumin ； hematoporphyrin ； singlet oxygen ； chemiluminescence ； photosensitization

國際替代計量

Chemiluminescence from Human Serum Albumin Oxidation by Singlet Oxygen by Singlet Oxygen

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