【摘要】 分别研究了二乙三胺五乙酸(DTPA)及2种衍生物二乙三胺五乙酸-双二甲酰胺(DTPA-BDMA)和二乙三胺五乙酸-双(异烟肼)(DTPA-B IN)对乳酸脱氢酶活性及酶促反应动力学的影响。结果表明,它们均可以抑制脱氢酶的活性,其抑制类型为竞争性的抑制作用,抑制常数分别为3.37、7.41、8.52μmol/L。紫外差谱结果表明,DTPA及其衍生物可以和酶分子作用,其羧基部分被包埋到分子内部,在酶分子的结合部位存在芳香族的氨基酸残基。DTPA与脱氢酶作用后使酶分子中的色氨酸荧光强度减弱,对酪氨酸的荧光没有明显影响。更多还原

【Abstract】 The enzymatic interactions between lactate dehydrogenase and diethylenetriamine pentaacetic acid(DTPA) and its derivatives bisdimethylamide-diethylenetriamine pentaacetic acid(DTPA-BDMA) and(bisisonicotinyl-)diethylenetriamine pentaacetic acid(DTPA-BIN) have been investigated.DTPA and its derivatives react as competitive inhibitors and inhibit the activity of lactate dehydrogenase,the inhibition constants are 3.37,7.41,8.52 μmol/L,respectively.The results from Ultraviolet-Visible difference spectroscopy indicate that after binding with lactate dehydrogenase molecule,the carboxyl groups of DTPA are embedded in an inner hydrophobic environment.DTPA and its derivatives could reduce the tryptophan fluorescence emission(intensity) of dehydrogenase and exhibit little effects on the tyrosine fluorescence intensity.更多还原