【摘要】 本文通过酶活性测定,荧光光谱和紫外光谱研究了外加Cu2+与烟草多酚氧化酶(简称PPO)的相互作用。结果表明,微量铜的加入能增加酶的活性,犤Cu2+犦/犤PPO犦为0.20左右时酶活性最大,犤Cu2+犦/犤PPO犦为0.91时,Cu2+开始表现出对PPO活性的抑制;Cu2+对PPO内源荧光的猝灭机制属于形成络合物所引起的静态猝灭,猝灭常数Ksv为8.0375×103L·mol-1;Cu2+的加入使PPO蛋白质分子构象发生变化,α-螺旋含量增加,多肽链及Trp和Tyr残基的芳杂环进一步向分子内收缩,疏水基团之间的疏水作用增强。更多还原

【Abstract】 The interaction between Cu2+and PPO(polyphenol oxidase) has been studied by employing enzymatic activity assay, fluorescence spectroscopy and UV/Visible spectroscopy. The results show that the activity of PPO was enhanced by the addition of Cu2+, reaching maximum when / was about 0.20, and then, the inhibition for it was appeared due to the existence of Cu2+. The quenching mechanism of the combination of Cu2+with PPO is a static quenching procedure, the quenching constant Ksv is 8.0375×103L·mol-1. The conformation of PPO is changed, the α helix content is increased, the polypeptide chain and the aromatic ring in Trp and Tyr residues are contracted to the inner of molecule, the hydrophobic interaction among hydrophobic groups enhanced after Cu2+was added to it.更多还原