High throughput screening reveals several new classes of glutamate dehydrogenase inhibitors
High throughput screening reveals several new classes of glutamate dehydrogenase inhibitors
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DOI：
10.1021/bi7018783
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发表时间：
2007-12-25
期刊：
影响因子：
2.9
通讯作者：
Smith, Thomas J.
中科院分区：
文献类型：
--
作者：
Li, Ming;Allen, Aron;Smith, Thomas J.
谷氨酸脱氢酶（GDH）已显示在胰腺β细胞的胰岛素分泌中起调节作用。最令人信服的证据来自胰岛素过多/高氨血症（HI/HA）综合征的特征，其中显性突变导致GTP抑制作用丧失，以及将亮氨酸（及其类似物BCH）激活GDH与刺激胰岛素分泌联系起来的研究。这表明GDH可能代表一种新的和新颖的药物靶点，以控制各种胰岛素紊乱。最近，我们证明，一个子集的绿色茶多酚是有效的谷氨酸脱氢酶抑制剂在体外，可以有效地阻止BCH刺激胰岛素分泌。在这些目前的研究中，我们使用高通量方法扩展了对GDH抑制剂的搜索，以筛选超过27，000种化合物。许多已知的和新的抑制剂与IC（50）的低微摩尔范围内确定。发现这些新的抑制剂通过明显不同的机制起作用，其中一些以正合作的方式抑制反应，仅一些化合物的抑制被ADP逆转，并且发现一种化合物稳定酶对抗热变性。因此，这些新化合物不仅是治疗GDH过度活跃的新线索，而且可用于剖析该酶的复杂变构性质。
Glutamate dehydrogenase (GDH) has been shown to play a regulatory role in insulin secretion by pancreatic beta-cells. The most compelling evidence of this comes from features of the hyperinsulism/ hyperammonemia (HI/HA) syndrome where a dominant mutation causes the loss of inhibition by GTP, and from studies that link leucine (and its analogue BCH) activation of GDH to stimulation of insulin secretion. This suggests that GDH may represent a new and novel drug target to control a variety of insulin disorders. Recently we demonstrated that a subset of green tea polyphenols are potent inhibitors of glutamate dehydrogenase in vitro and can efficaciously block BCH stimulation of insulin secretion. In these current studies, we extend our search for GDH inhibitors using high throughput methods to pan through more than 27,000 compounds. A number of known and new inhibitors were identified with IC(50)s in the low micromolar range. These new inhibitors were found to act via apparently different mechanisms with some inhibiting the reaction in a positively cooperative manner, the inhibition by only some of the compounds was reversed by ADP, and one compound was found to stabilize the enzyme against thermal denaturation. Therefore, these new compounds not only are new leads in the treatment of hyperactive GDH but also are useful in dissecting the complex allosteric nature of the enzyme.