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本文比较酵母GAPDH在盐酸胍溶液中的剩余活力、紫外差光谱、内源荧光及酶的NAD荧光衍生物410 nm特征荧光的变化结果表明:全酶及脱辅基酶在低于0.5mol/L胍溶液中完全失活,同时伴有酶分子中芳香族残基环境的紫外吸收和内源荧光的变化,以及酶荧光衍生物410 nm特征荧光强度的显著降低和发射峰位的红移.失活动力学过程为快慢两相,快相一级反应常数比内源荧光降低的单相常数至少大3个数量级以上.410 nm特征荧光降低的动力学过程也为快慢两相,快相一级反应速度远大于内源荧光降低反应速度,并与失活速度相近.以上结果表明:低浓度胍首先扰乱活性部位的空间构象导致酶的失活,分子整体构象的完全去折叠需要更高浓度的盐酸胍.
In this paper, we compared the remaining vitality of yeast GAPDH in guanidine-HCl solution, UV-vis spectra, endogenous fluorescence and the characteristic fluorescence at 410 nm of the NAD fluorescent derivative of enzyme. The results showed that the activities of holoenzyme and apo- Guanidine solution, with the changes of the ultraviolet absorption and endogenous fluorescence of the aromatic residues in the enzyme molecule, and the marked decrease of the 410 nm fluorescence intensity and the red shift of the emission peak. The kinetic process of the kinetics is fast and slow, and the first-order reaction constant of the fast phase is at least three orders of magnitude greater than the single-phase constant of the reduction of endogenous fluorescence. The kinetics of the 410 nm characteristic fluorescence decrease is also one of fast and slow phase, Far greater than the endogenous fluorescence to reduce the reaction rate and deactivation rate similar to the above results show that: low concentrations of guanidine first disrupt the spatial conformation of the active site leads to enzyme inactivation, complete conformational complete unfolding of the molecule requires a higher concentration of guanidine hydrochloride .