胆碱脱氢酶光谱性质的研究  

Studies on the Spectral Properties of Choline Dehydrogenase

作　　者：傅晓红[1] 林其谁[1] 

机构地区：[1]中国科学院上海生物化学研究所分子生物学国家重点实验室

出　　处：《生物化学与生物物理学报》1997年第2期213-219,共7页

摘　　要：胆碱脱氢酶（ＣＤＨ）蛋白质部分内源荧光发射峰在３３５ｎｍ，并不受底物的影响，但底物可改变辅基ＦＡＤ部分的内源荧光光谱。应用ＦＴＩＲ技术研究了增溶ＣＤＨ的二级结构，其结果如下：５３．４％α－螺旋，２４．５％β－片层，１３．９％３１０－螺旋及０．５％β－回折。在ＣＤＨ处于非底物结合状态时，分子内部结构表现为α－螺旋以及β－片层优势构象，呈现出球状蛋白样的空间结构特征。在与底物作用过程中，３１０－螺旋的比例逐渐上升至４２％左右，与此同时α－螺旋结构则降低到３５％。提示了底物诱导ＣＤＨ分子内部发生了蛋白分子的重新折叠。The addition of the substrate didn't show any influence on the intrinsic emission spectra of purified CDH, which had a maximum at 335 nm. On the other hand, the 520 nm fluorescence of CDH increased after the addition of substrate. The secondary structure of solubilized CDH was examined by Fourier transform infrared spectroscopy. The percentage distribution of its secondary structure assignment had been obtained: 53.4% α helix, 24.5% β sheet, 13.9% 3 10 helix and 0.5% β turn. The predominant conformation of CDH was α helix and β sheet when there was no substrate. After the addition of substrate, the percentage of 3 10 helix structure increased to 42%, whereas that of α helix structure decreased to 35%, indicating that the conformation of CDH changed significantly after the binding of substrate to the enzyme.

关 键 词：胆碱脱氢酶 胆碱 光谱 性质 

分 类 号：Q556.02[生物学—生物化学]