胆碱脱氢酶的变性及其构象研究  

Studies on the Denaturation and Conformation of Choline Dehydrogenase

作　　者：傅晓红[1] 蔡澎[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,200031

出　　处：《生物化学与生物物理学报》1997年第1期82-87,共6页

摘　　要：增溶胆碱脱氢酶(CDH)在较低的pH条件下易于失活,底物胆碱的存在有助于提高其pH稳定性。热变性酶蛋白分子中β结构所占比例上升,α螺旋结构比例下降,其中β结构的变化主要来自于β回折和3_(10)螺旋的贡献,底物对CDH的热变性具有一定的保护作用。在完全SDS变性和有底物保护的蛋白质分子中3_(10)螺旋的比例分别为33%和31.2%,β回折比例分别为29%和10.6%,此外在α螺旋、无规卷曲等所占的比例方面,在底物保护下经变性处理的CDH蛋白的构象都与天然胆碱脱氢酶相近。The substrate choline was able to improve the pH stability of choline dehydrogenase (CDH). It was found that during the thermal denaturation there were an increase of β-structure and a decrease of the α-helix content. Changes in β-structure were attributed to β-turn and 310-helix. The substrate had a protective effect on CDH thermal denaturation. The proportion of 3_(10)-helix content of the SDS-denatured protein and that in the presence of substrate was 33 % and 31.2% respectively; while, the corresponding proportion of β-sheet was 29% and 10.6 %, respectively. Moreover, when the absorption proportion of α-helix, random coil and the side-chain of tyrosine residues were concerned, it was found that the spectral property of the CDH treated by denaturants in the presence of substrate were rather similar to that of the non-denatured enzyme.

关 键 词：胆碱脱氢酶 变性 构象 

分 类 号：Q554.901[生物学—生物化学]