动力学和结构特性的抑制enoyl三氯生(酰基载体蛋白)还原酶。
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Rowsell病房WH Holdgate GA,年代,麦克莱恩如Pauptit RA,克莱顿E,尼科尔斯WW,书詹,米舒尔CA,裘德哒,Mistry,蒂姆斯D, Camble R,黑尔斯新泽西州,布里顿CJ,泰勒信息战
动力学和结构特性的抑制enoyl三氯生(酰基载体蛋白)还原酶。
生物化学。1999年9月21日,38 (38):12514 - 25。
- PubMed ID
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10493822 (在PubMed]
- 文摘
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作为抗菌剂三氯生是广泛使用在皮肤的产品,漱口水和牙膏。最近的研究表明,抗菌活性的结果绑定到enoyl(酰基载体蛋白)还原酶(EC 1.3.1.9 EACPR)。我们第一次认识到三氯生的抑制能力EACPR大肠杆菌的酶和测试化合物的高吞吐量的屏幕是preincubated NAD(+),这是一个产品的反应。三氯生所需的50%的浓度抑制接近50%的酶浓度,表明自由化合物被绑定到EACPR耗尽。没有预培养和NAD(+),由150海里三氯生的抑制程度逐渐增加超过几分钟。发病时更迅速抑制NAD (+)。凝胶过滤和质谱分析表明,三氯生是可逆的抑制。稳态分析是为了避免损耗自由抑制剂和变化程度的抑制。结果表明三氯生结合E-NAD(+)复杂,离解常数约20 - 40点。三氯生是竞争动力学对NADH,给一个抑制常数38点零NADH和饱和NAD (+)。 Uncompetitive kinetics are observed when NAD(+) is varied, giving an inhibition constant of 22 pM at saturating NAD(+). By following regain of catalytic activity after dilution of EACPR that had been preincubated with triclosan and NAD(+), the rate constant for dissociation of the inhibitor (k(off)) is measured as 1.9 x 10(-4) s(-1). The association rate constant (k(on)) is estimated as 2.6 x 10(7) s(-1) M(-1) by monitoring the onset of inhibition during assays started by addition of EACPR. As expected, the ratio k(off)/k(on) = 7.1 pM is similar to the inhibition constants from the steady-state studies. The crystal structure of E. coli EACPR in a complex with coenzyme and triclosan has been determined at 1.9 A resolution, showing that this compound binds in a similar site to the diazaborine inhibitors. The high affinity of triclosan appears to be due to structural similarity to a tightly bound intermediate in catalysis.