Carbonic anhydrase inhibitors. Zonisamide is an effective inhibitor of the cytosolic isozyme II and mitochondrial isozyme V: solution and X-ray crystallographic studies
Carbonic anhydrase inhibitors. Zonisamide is an effective inhibitor of the cytosolic isozyme II and mitochondrial isozyme V: solution and X-ray crystallographic studies
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DOI：
10.1016/j.bmcl.2005.03.032
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发表时间：
2005-05-02
影响因子：
2.7
通讯作者：
Supuran, CT
中科院分区：
文献类型：
--
作者：
De Simone, G;Di Fiore, A;Supuran, CT
抗癫痫药物唑尼沙胺被认为是锌酶碳酸酐酶（CA, EC 4.2）的弱抑制剂。1.1)（对胞质同工酶11的K值为4.3 μ M）。这里我们证明这是不正确的。zonisamide在经典条件下测试hCA II的CO2水解酶活性，酶和抑制剂溶液孵养时间为15 min， K-1为10.3 mu M。然而，当酶与抑制剂之间的孵育时间延长至1d h时，得到的K(1)为35.2 nM，与临床使用的磺胺类/磺胺类药物乙酰唑肽、甲唑胺、乙氧唑胺和托吡酯的K(1)s在5.4-15.4 nM范围内相同。这些化合物对人线粒体同位酶hCA V的抑制作用也通过丹西酰胺竞争结合实验进行了测试，结果表明唑尼沙胺和托吡酯是有效的抑制剂，K(1)s在20.6-25.4 nM范围内。hca11与唑尼沙酰胺加合物的x射线晶体结构也在1.70 a的分辨率下进行了解析，结果表明，磺胺部分参与了与Zn（II）离子和残基Thr199和Glu106的经典相互作用，而苯并恶唑环则面向活性位点的疏水半部分，与残基Gln92、Vall2l、Phe131、Leu198、Thr200、Pro202建立了大量强范德瓦尔斯相互作用（< 4.5 a）。(c) 2005 Elsevier Ltd版权所有。
The antiepileptic drug zonisamide was considered to act as a weak inhibitor of the zinc enzyme carbonic anhydrase (CA, EC 4.2. 1.1) (with a K, of 4.3 mu M against the cytosolic isozyme 11). Here we prove that this is not true. Indeed, testing zonisamide in the classical assay conditions of the CO2 hydrase activity of hCA II, with incubation times of enzyme and inhibitor solution of 15 min, a K-1 of 10.3 mu M has been obtained. However, when the incubation between enzyme and inhibitor was prolonged to 1d h, the obtained K-1 was of 35.2 nM, of the same order of magnitude as that of the clinically used sulfonamides/sulfamates acetazolantide, methazolamide, ethoxzolamide and topiramate (K(1)s in the range of 5.4-15.4 nM). The inhibition of the human mitochondrial isozyme hCA V with these compounds has been also tested by means of a dansylamide competition binding assay, which showed zonisamide and topiramate to be effective inhibitors, with K(1)s in the range of 20.6-25.4 nM. The X-ray crystal structure of the adduct of hCA 11 with zonisamide has also been solved at a resolution of 1.70 A, showing that the sulfonamide moiety participates in the classical interactions with the Zn(II) ion and the residues Thr199 and Glu106, whereas the benzisoxazole ring, is oriented toward the hydrophobic half of the active site, establishing a large number of strong van der Waals interactions (< 4.5 A) with residues Gln92, Vall2l, Phe131, Leu198, Thr200, Pro202. (c) 2005 Elsevier Ltd. All rights reserved.