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本文采用差示扫描量热法(DSC),研究了水合醛缩酶在含水量h从0.08g/g至2.28g/g范围内的热变性行为。实验结果表明,当h=0.08g/g时,水合醛缩酶样品的温度扫描热谱图呈现了两个吸热峰,其中低温峰很小,高温峰很大。随着h的增大,低温峰变得更小,高温峰则出现了分峰现象。当h=0.22g/g时,低温峰消失,高温峰则分裂成了两个独立的吸热峰。随着h的继续增大,其中前峰的位置不断移向低温,直至h_0.65g/g时,才不再变化。后峰的位置则始终保持不变。当再进行第二次温度扫描时,前峰消失,而后峰却能再现。本文给出了两峰在不同含水量时的转变温度、转变焓和转变焓之和,以及它们与含水量的关系。最后,对上述诸峰的起因作了分析讨论,认为低温峰可能起因于水合醛缩酶结晶的熔化作用,前峰和后峰可能起因于醛缩酶中两种A亚基的热变性。
In this paper, differential scanning calorimetry (DSC) was used to study the heat-denatured behavior of hydrated aldolase in the range of water content from 0.08 g / g to 2.28 g / g. The experimental results show that when h = 0.08g / g, the thermogram of hydrated aldolase showed two endothermic peaks, of which the low temperature peak was small and the high temperature peak was large. With the increase of h, the low temperature peak becomes smaller, and the high temperature peak shows the phenomenon of sub-peak. When h = 0.22g / g, the low temperature peak disappears and the high temperature peak splits into two independent endothermic peaks. As h continues to increase, the position of the former peak continues to shift to low temperature until h_0.65g / g, it no longer changes. After the peak position is always unchanged. When the second temperature scan again, the former peak disappears, but then the peak can reproduce. In this paper, we give the sum of the transition temperature, the enthalpy of transformation and the enthalpy of the transition of the two peaks at different water contents, and their relationship with the water content. Finally, the causes of the above peaks are analyzed and discussed. It is considered that the low temperature peak may be caused by the melting of hydrated aldolase crystals. The pre-peak and the post-peak may result from the thermal denaturation of two A subunits in the aldolase.