The model enzymatic inhibition mechanism by inhibitor oxamate has been studied at the HF/3-21G level. All the conclusions can be summarrized as follows:(a)the conformations of the optimized model inhibitor oxamate and substrate are much more similar with each other,which leads to an unidentified action of the substrate and inhibitor by L- lactate dehydrogenase(LDH); (b)the electronic distribution of the inhibitor is favorable for the combination of oxamate to LDH active site; (3)the space of LDH active site is contracted by the induced-fit interaction between the LDH and the inhibitor;(4) the molecular fragment methyl of substrate and the residue Gln-102 of LDH probably play an important role in the enzymatic reaction.%应用HF/3-21G研究了抑制剂H2N－CO－COO－对L-乳酸脱氢酶的抑制成因.结果表明,酶被抑制的主要原因有:(1)抑制剂与底物的稳定构象态在结构上极为相似,导致酶不能有效识别底物;(2)模型抑制剂各原子所带净电荷的优势使抑制剂更易与酶活性中心结合;(3)抑制剂通过对酶的诱导契合作用使酶活性中心的空间被缩小;(4)对活性中心有关结构的分析表明,底物的甲基分子片以及酶的氨基酸残基Gln102,对催化反应能否顺利进行,影响极大.
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