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肌红蛋白通常在无光条件下可进行输氧、储氧等重要功能,实验中我们发现紫外光照射可促进氧合肌红蛋白(MbO2)的氧化反应,证实其在光照时部分生理功能会发生变化。紫外-可见(UV-Vis)吸收光谱数据显示,光照射时MbO2的Soret带最大吸收波长蓝移、Q吸收带544和580 nm处还原峰强度下降,说明紫外光光照促进O2解离, MbFe(Ⅱ)可被氧化至MbFe(Ⅲ)。四种波长光对光照氧化的影响程度为254 nm > 280 nm >430 nm > 409 nm;通入CO气体时氧合肌红蛋白较难发生光照氧化反应,即Fe的第六配位强度影响反应程度;溶液中的H+或OH-对光照氧化反应有促进作用; 254、280 nm波长光照射时,苯丙氨酸(Phe)、酪氨酸(Tyr)、色氨酸(Trp)三种游离氨基酸均促进光照氧化反应的进行,而409、430 nm波长光照射时三种游离氨基酸对光照氧化反应的影响较小。以上数据表明体内光诱导MbO2氧化反应过程中蛋白质内的Fe(Ⅱ)能否被光照激发形成未成对电子处于激发态是O2离去和二价铁被氧化的关键。 相似文献
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Rajasekhara Nerimetla Charuksha Walgama Ranjith Ramanathan Sadagopan Krishnan 《Electroanalysis》2014,26(4):675-678
We report here for the first time application of electrochemical kinetics to understand the myoglobin redox‐properties at three relevant meat pH conditions. We investigated the kinetics of oxymyoglobin formation electrochemically using films of myoglobin coated on high‐purity graphite electrodes. Three pH conditions corresponding to the physiological state (pH 7.4), stressed animal muscle (pH 6.4), and post‐mortem meat (pH 5.6) were examined in this study. Our findings show that slower metmyoglobin reduction rate and diminished oxygen‐affinity cause the discoloration of red‐meat at low acidic pH‐conditions in comparison to the physiological pH 7.4. 相似文献
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ZHOU Hua-wei CAO Hong-yu TANG Qian MA Jun-yan ZHANG Ying-ying ZHENG Xue-fang 《高等学校化学研究》2011,27(6):1060-1064
Photodissociation of oxygen from oxymyoglobin(oxyMb) was investigated by means of fluorescence spectroscopy. One of the most important findings of the photodissociation of oxyMb was the discovery of two processes which were affected by excitation intensity, temperature, solvent viscosity, and excitation wavelength. Process I(PI) corresponded to oxygen escaping from the binding site at ferrous heme iron atom within the porphyrin ring into the heme pocket, whereas process II(PII) was ascribed to oxygen escaping from the heme pocket into the solvent. To elucidate this interesting phenomenon, we proposed a model that oxygen encountered two barriers on its way from the binding site at the ferrous heme iron to the solvent. Reversibility and wavelength sensitivity of the photodissociation were also observed. 相似文献
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