激光诱导游离半胱氨酸对血红蛋白反应动力学的影响及机理  

Effect and Mechanism of Photo-induced Hemoglobin Kinetics Reaction with Free Cysteine

作　　者：曹洪玉[1,2] 史飞[3] 唐乾[1,2] 王立皓 郑学仿[1,3,2] CAO Hongyu;SHI Fei;TANG Qian;WANG Lihao;ZHENG Xuefang(College of Life Science and Biotechnology,Dalian University,Dalian 116622,Liaoning,P.R.China;College of Environmental and Chemical Engineering,Dalian University,Dalian 116622,Liaoning,P.R.China;Liaoning Key Laboratory of Bio-Organic Chemistry,Dalian University,Dalian 116622,Liaoning,P.R.China)

机构地区：[1]大连大学生命科学与技术学院,辽宁大连116622 [2]大连大学辽宁省生物有机化学重点实验室,辽宁大连116622 [3]大连大学环境与化学工程学院,辽宁大连116622

出　　处：《影像科学与光化学》2018年第2期149-160,共12页Imaging Science and Photochemistry

基　　金：国家自然科学基金项目(21571025;21601025;21271036;21601023);辽宁省教育厅科学技术研究项目(L2013471)资助

摘　　要：血红蛋白(hemoglobin,Hb)是具有环状共轭结构的呼吸蛋白,可以吸收特定波长的光,通过血红素辅基的结构变化,进而影响血红蛋白生物功能的表达。研究中发现,紫外区波长光照射血红蛋白能够引起其结构发生一定的变化,光照实验中加入游离半胱氨酸有助于高铁血红蛋白(methemoglobin,metHb)结构的稳定。266nm光照后高铁血红蛋白、去氧血红蛋白(deoxyhemoglobin,deoxyHb)、氧合血红蛋白(oxyhemoglobin,HbO2)和碳氧血红蛋白(carboxyhemoglobin,HbCO)均被激发至各自相应激发态,其Soret带谱峰衰减至基态的时间大致相同;加入游离半胱氨酸后,半胱氨酸与各激发态铁卟啉发生电子传递,在直接和间接地进行了电子传递后,激发态铁卟啉衰减时间发生变化,metHb、HbO2和HbCO衰减时间明显延长,但deoxyHb变化相对较小。对瞬态吸收光谱、动力学曲线和紫外-可见吸收光谱综合分析可知,4种形态血红蛋白被光激发至各自激发态后,铁卟啉均反应形成具有一空位的六配位平面结构状态。Hemoglobin(Hb)is a respiratory protein with cyclic conjugated structure,which can absorb light at specific wavelengths and influence the expression of hemoglobin by the structural changes.It was found that the ultraviolet light irradiation could influence the structural changes of Hb,and added free cysteine contributes to the structure stability of methemoglobin(metHb)in irradiation experiment.Irradiated by 266 nm laser,metHb,deoxyhemoglobin(deoxyHb),oxyhemoglobin(Hb02)and carboxyhemoglobin(HbCO)are excited to their excited states,and the decay processes to the ground state indicated with their corresponding Soret band peak have almost the same time.After adding free cysteine,the electron of cysteine can directly or indirectly transfer to iron porphyrin with the variation of the decay time of excited state iron porphyrin.The significant prolongations of decay time are observed on the photo-irradiated metHb,Hb02 and HbCO,while slight influences are detected on the photo-irradiated deoxyHb.According to transient absorption spectroscopy,kinetic curves and UV-Vis spectra,while the four forms of hemoglobin are excited to the excited state,their iron porphyrin is reacted to the state of six-coordinated planar structure with one empty coordination position.

关 键 词：血红蛋白 光诱导 激光闪光光解 半胱氨酸 电子传递 

分 类 号：O629.7[理学—有机化学] O643.12[理学—化学]