中文摘要：

为了了解稀土元素与酶相互作用的化学机理，用紫外-可见（UV-Vis）吸收光谱技术和电化学方法研究了La^3＋与过氧化物酶（POD）的模型化合物，微过氧化物酶-8（MP-8）或微过氧化物酶-11（MP-11）的相互作用机理．La^3＋优先与MP-8或MP-11分子中血红素卟啉环上的2个丙酸基团的羰基氧发生键合作用，使它们的聚集程度降低，卟啉环的非平面性增加，由于MP-8分子聚集的倾向要小于MP-11，La^3＋使MP-8聚集程度的降低和卟啉环非平面性增加的程度要大于MP-11．由于MP-11的肽链较长而能形成螺旋状构象，使肽链上的羰基基团被包埋在肽链的疏水基团中，因此。La^3＋与MP-11中肽链上的羰基氧基本上不能发生键合作用．而MP-8的肽链较短，不能形成螺旋状结构，La^3＋也能与肽链上的羰基氧发生键合作用．

英文摘要：

In order to understand the chemical mechanism of the interaction of the enzymes with the rare earth elements, the mechanism of the interaction between La^3＋ and the model of POD, MP-8 or MP-11 was studied using UV-Vis absorption spectroscopy and electrochemical technique. It was found that La^3＋ was bound firstly to the carbonyl oxygen of the metacetonic acid group in the heine group of the MP-8 or MP-11 molecule, resulting in the decrease of their aggregation extents and the increase of the non-planarity of the porphyrin group. The decrease extent of the aggregation of the molecules and then the increase extent of the nonplanadty of the porphyrin group for MP-8 due to La^3＋ binding were greater than those for MP-11 because the aggregation tendency of MP-8 was less than that of MP-11. The peptide of MP-11 was long enough to form the helical conformation, thus, the carbonyl oxygen in the peptide would be embedded in the hydrophobic microenvironment of the peptide, and La^3＋ was not easy to coordinate with the carbonyl oxygen in the peptide of MP-11. However, the peptide of MP-8 was relatively short, it could not form the helical conformation and therefore, La^3＋ was easy to interact with the carbonyl oxygen in the peptide of MP-8.