利用脉冲激光技术研究哺乳动物碳氧血红蛋白光解量子产率  

Quantum yields in photolyses of mammalian carboxy-hemoglobin studied by pulsed laser pump-probe technique

作　　者：赵瑾瑜[1] 渠敏[1] 李家璜[2] 张铮[3,4] 张淑仪[1] 水修基[1] 杨跃涛[1] 华子春[2] 

机构地区：[1]南京大学声学研究所近代声学实验室,南京210093 [2]南京大学生命科学院医药生物技术实验室,南京210093 [3]南京市第一医院 [4]南京大学医学院附属医院,南京210006

出　　处：《南京大学学报（自然科学版）》2011年第2期155-163,共9页Journal of Nanjing University（Natural Science）

基　　金：国家自然科学基金(11074125)

摘　　要：本文利用脉冲光解法测量了哺乳动物碳氧血红蛋白的光解反应的量子产率.脉冲光解法是利用一束波长为532 nm、脉冲宽度为8 ns、重复频率为10 Hz的脉冲激光照射碳氧血红蛋白溶液,使其发生光解反应.考虑到碳氧血红蛋白溶液和其光解产物脱氧血红蛋白的光吸收系数不同,可利用另一束波长为432 nm的连续激光检测溶液在光解前、后的透射率的变化,以测定溶液的光解量子产率.利用此实验系统,对人、猪、牛、马和兔等5种哺乳动物的碳氧血红蛋白的光解量子产率进行了测量和研究,结果表明,不同物种的光解量子产率各不相同,其中猪、牛、马的碳氧血红蛋白的光解量子产率很接近,兔的碳氧血红蛋白的光解量子产率与其他物种的差异最大.最后,对测量的结果从血红蛋白的氨基酸序列、氢键和盐桥排布、四级结构等方面进行了分析与讨论.Hemoglobin(Hb) as the allosteric protein,in photo-dissociations of liganded Hb has been studied widely.The mechanisms describing the cooperative binding of CO and other ligands to hemoglobins has been the subject of extensive studies as an important fundamental problem for a long time.In this paper,the quantum yields in photolyses of carboxy-hemoglobins(HbCO) of mammals,such as human,pig,bovine,horse and rabbit,are investigated by the optical pump-probe technique,in which the quantum yield is defined as the molecular number of photoproduct species divided by the absorbed photon number.In the optical pump-probe technique,the HbCO of the mammals are irradiated by a pulsed pumping laser beam with the wavelength 532 nm,pulse width 8 ns and the repetition frequency 10 Hz,then the HbCO is photo-dissociated.Meanwhile,another continuous optical beam with the wavelength 432 nm is used as a probe beam to detect the absorbance change induced by the photo-dissociation before and after the laser pulse illuminating HbCO.In the experiments,a solution with the recognized quantum yield Φ0 is taken as a standard solution,and adjust the optical absorption(at the wavelength 532 nm) of the measured solutions to be the same data as that of the standard solution,then the quantum yield Φ of the measured solution can be obtained by comparing the variations of the optical absorption(at 432 nm) induced by the photolyses of the solutions with those of the standard solution measured at the same experimental conditions.The measured results show that the quantum yields of the photolyses of the HbCO are different for varies mammals,but for three of the mammals,i.e.,pig,bovine and horse,the photolysis quantum yields of their HbCO are very close.However,for the HbCO of rabbit,the quantum yield is much smaller than the others.Finally,the results are analyzed and discussed.To explain the differences among them,some analyses and discussions on the differences of the amino acid sequences of the five Hb,and the tetramer structures,as well as the sal

关 键 词：碳氧血红蛋白 光解反应 量子产率 脉冲激光激发—检测技术 

分 类 号：Q518.4[生物学—生物化学]