Christopherson R I, Morrison J F
Biochemistry. 1985 Feb 26;24(5):1116-21. doi: 10.1021/bi00326a008.
Investigations have been made at pH 6.0 of the effect of chorismate and adamantane derivatives on the mutase and dehydrogenase activities of hydroxyphenylpyruvate synthase from Escherichia coli. When used over a wide range of concentrations, chorismate 5,6-epoxide, chorismate 5,6-diol, adamantane-1,3-diacetate, adamantane-1-acetate, adamantane-1-carboxylate, and adamantane-1-phosphonate give rise to nonlinear plots of the reciprocal of the initial velocity of each reaction as a function of the inhibitor concentration. The inhibitors do not induce the enzyme to undergo polymerization and have only a small effect on the S20,w value of the enzyme as determined by using sucrose density gradient centrifugation. At low substrate concentration, low concentrations of adamantane-1-acetate cause activation of both the mutase and dehydrogenase activities while at higher concentrations this compound functions as an inhibitor. When chorismate and prephenate are varied over a wide range of concentrations, double-reciprocal plots of the data indicate that the reactions exhibit positive cooperativity. The addition of albumin eliminates the cooperative interactions associated with substrates but has little effect on those associated with inhibitors.
已经在pH 6.0条件下研究了分支酸和金刚烷衍生物对大肠杆菌中羟苯丙酮酸合酶的变位酶和脱氢酶活性的影响。当在广泛的浓度范围内使用时，分支酸5,6-环氧化物、分支酸5,6-二醇、金刚烷-1,3-二乙酸酯、金刚烷-1-乙酸酯、金刚烷-1-羧酸盐和金刚烷-1-膦酸盐会使每个反应的初始速度的倒数与抑制剂浓度的函数关系呈现非线性曲线。这些抑制剂不会诱导酶发生聚合，并且对通过蔗糖密度梯度离心法测定的酶的S20,w值只有很小的影响。在低底物浓度下，低浓度的金刚烷-1-乙酸酯会激活变位酶和脱氢酶的活性，而在较高浓度下，该化合物则起抑制剂的作用。当分支酸和预苯酸在广泛的浓度范围内变化时，数据的双倒数图表明反应呈现正协同性。添加白蛋白消除了与底物相关的协同相互作用，但对与抑制剂相关的协同相互作用影响很小。
