| Chapter 1 Briefly introduced the research on Tannin and interaction of Tannin with proteins and the classic theory for their interaction. What's more, the significance and contents of this paper were presented.Chapter 2 The interaction of TA and Trypsin were studied by fluorescence spectra. The postulates were researched and finally fixed. There were two stages, rapid reaction stage and slow reaction stage, during the interaction of TA with Trypsin. Considering the two stages, titration and interact for 24h were applied at different pH. Strong quenching effect and red shift of maximum fluorescence were observed in both stages. It showed that their interaction belongs to static quenching. The appearance KA and n were calculated. Thermodynamic parameters were also obtained. It can be referred that the hydrophobic forces were the main force during the interaction, but it can change with the changing of pH value. Thus, it comes to the conclusion that the slow reaction stage was more stable than rapid reaction stage.Chapter 3 The effect of TA on enzyme activity of Trypsin were studied. The results showed that TA inhibit the enzyme activity of Trypsin rapidly. According to the Lineweaver-Burk plots, Km were calculated to be 1.7×10-5 mol·L-1. The inhibition type were determined to be the compound of competed and incompeted inhibition. The value of Ki and Ki' were calculated to be 4.55×10-6mol·L-1, 6.50×10-5mol·L-1 separately; Vmapp and Kmapp were also gained. TA can not only quenched the fluorescence of Trypsin, but also inhibit the enzyme activity. What's more, the value of 1/Ki were accord with the value of KA, which gained by using the fluorescence spectra method.Chapter 4 The effect of TA on BSA were also researched at 25℃, pH 7.4. The results showed that TA can quench the fluorescence of BSA, induce the red shift of maximum wavelength. Further study showed that the quenching effect of TA to BSA belongs to static quenching. So titration and interact for 24 hours were applied. KA and n were determined to be 3.16×105 L·mol-1,...
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