作　　者： ; ; ; ; ; ;

机构地区： 华南农业大学生命科学学院

出　　处： 《华南农业大学学报》 2008年第3期37-41,共5页

摘　　要： 利用紫外吸收光谱、荧光发射光谱研究了二甲基亚砜对木瓜蛋白酶活性与构象的影响.当二甲基亚砜溶液为低体积分数时,木瓜蛋白酶活性比对照(φ二甲基亚砜=0)有所上升;随着二甲基亚砜溶液体积分数升高,木瓜蛋白酶活性却不断降低,紫外吸收光谱的第1吸收峰明显地向长波长方向移动;且紫外光吸收峰值逐渐降低,到φ二甲基亚砜为50%时又有所升高.木瓜蛋白酶在不同体积分数二甲基亚砜溶液中荧光发射光谱发生变化.在φ二甲基亚砜为5%、10%、20%二甲基亚砜溶液中,与对照(φ二甲基亚砜=0)相比,酶对底物分子的亲和力降低;最大反应速度上升.结果表明:低体积分数的二甲基亚砜对木瓜蛋白酶的构象影响较小,酶活性上升;高体积分数的二甲基亚砜对木瓜蛋白酶的构象影响较大,酶活性下降. The effects of dimethyl sulfoxide（DMSO） on the activity and conformation of papain by ultraviolet and fluorescence spectra were studied. The papain activity in the reaction system contained low volume fraction of DMSO increased as compared with that in control experiment （φ dimethyl sulfoxide = 0）. However, with farther increasing the volume fraction of DMSO, the activity of papain constantly decreased, the first ultraviolet absorption peak exhibited a red shift, and when reduced up to φ dimethyl sulfoxide of 50% the first ultraviolet absorption increased. In different volume fraction of DMSO, the papain activity in fluorescence emission spectra had significant changes. As compared with the control experiment （φ dimethyl sulfoxide = 0）, the Km decreased, but the Vm= increased in φ dimethyl sulfoxide of 5%, 10% and 20%. It was demonstrated that, in low volume fraction of DMSO, the papain activity increased and its conformation had less changes, however, in high volume fraction of DMSO, the papain activity decreased and its conformation had more changes.

关 键 词： 木瓜蛋白酶 二甲基亚砜 紫外吸收光谱 荧光发射光谱

领　　域： [生物学]