通过活力测定,紫外差光谱、多维荧光光谱及差示扫描量热分析,研究了0.23～0.61T稳恒磁场对两种不同构象状态的离体牛肝过氧化氢酶的生物学效应.被选择用于研究的酶的构象状态分别为4?℃的钝化状态和25?℃的活化状态,二者具有明显不同的构象.4?℃时,酶分子处于钝化状态,经0.23～0.61T稳恒磁场处理不同的时间后,几乎不表现出任何磁生物学效应;25?℃时,酶分子处于活化状态,经磁场处理后,表现出明显的磁生物学效应:酶活力增加,同时构象发生变化.构象变化导致λ210～310?nm紫外差光谱的出现、荧光偏振度的增加、在λ330?nm荧光发射峰发射强度的改变及差示扫描量热曲线的产生.研究结果表明:不同的初始构象状态可能是产生不同磁效应的根本原因.%Biological effects of 0.23～0.61T static magnetic fields on vitro catalase from bovine liver with two different conformation were studied in this paper by way of activity assay, analyses of ultraviolet differential spectra, multiple dimension fluorescence spectra, and differential scanning calorimetric analyses. The selected conformationals were 4?℃ inhibitive and 25?℃ active states. The enzyme of 4?℃ have different conformation from that of 25?℃. After allowed to stand under 0.23～0.61T magnetic fields for various periods of time, as far as the enzymatic solution of 4?℃ was concerned, in which temperature the enzymatic molecules were in inhibitive state, the enzyme showed little biological effects judging by activity assay and spectrum analyses; by contrast, when the temperature of the natural enzymatic solution was 25?℃, in which temperature the enzyme molecule were activated, after it was exposed in various intensities of magnetic fields for various periods of time the enzyme showed distinct biological effects: its activities rose, and conformation also changed as well. Conformational changes resulted in wavelength λ210～310?nm ultraviolet differential spectra, fluctuations of fluorescence intensity at λ330?nm emission peak, increment of fluorescence polarization, and emersion of differential scanning calorimetric curves. Different effects of magnetic fields on enzyme between 4?℃ inhibitive and 25?℃ active states may be essentially caused by the difference of their initial conformational states when they were treated in the same setting.
展开▼
