Gutfreund H, Cantwell R, McMurray C H, Criddle R S, Hathaway G
Biochem J. 1968 Feb;106(3):683-7. doi: 10.1042/bj1060683.
The inhibition of lactate dehydrogenase at high pyruvate concentration was studied in three ways. First, a rapid decrease in the rate of the enzyme reaction was observed; secondly, the rate of formation of a pyruvate-NAD(+) compound was followed by the change in E(325); thirdly, the rate of quenching of the protein fluorescence was measured. The data obtained at pH6.0 at different temperatures and ionic strengths as functions of pyruvate, NAD(+) and enzyme concentrations show that the extent of inhibition can be correlated with the reversible formation of a compound between pyruvate and enzyme-bound NAD(+). It is suggested that the detailed kinetic analysis of the formation of this abortive ternary compound will give pertinent information about properties of the enzyme-NAD(+) compound involved in the normal catalytic process.
在高丙酮酸浓度下，通过三种方式研究了乳酸脱氢酶的抑制作用。第一，观察到酶反应速率迅速下降；第二，通过E(325)的变化跟踪丙酮酸-NAD(+)化合物的形成速率；第三，测量蛋白质荧光猝灭速率。在pH6.0、不同温度和离子强度下，作为丙酮酸、NAD(+)和酶浓度的函数所获得的数据表明，抑制程度与丙酮酸和酶结合的NAD(+)之间化合物的可逆形成相关。有人提出，对这种无效三元化合物形成的详细动力学分析将给出有关正常催化过程中所涉及的酶-NAD(+)化合物性质的相关信息。
