Kotthaus Jürke, Schade Dennis, Muschick Nikola, Beitz Eric, Clement Bernd
Department of Pharmaceutical and Medicinal Chemistry, Pharmaceutical Institute, Christian-Albrechts-University of Kiel, Gutenbergstrasse 76-78, D-24118 Kiel, Germany.
Bioorg Med Chem. 2008 Dec 15;16(24):10205-9. doi: 10.1016/j.bmc.2008.10.058. Epub 2008 Oct 29.
Recent studies demonstrated that inhibition of dimethylarginine dimethylaminohydrolase (DDAH) activity could be a new strategy to indirectly affect nitric oxide (NO) formation by elevating N(omega)-methylated L-arginine (NMMA, ADMA) levels. This approach is an alternate strategy for the treatment of diseases associated with increased NO-concentrations. To date, three classes of potent inhibitors are known: (1) pentafluorophenyl sulfonates (IC(50)=16-58 microM, PaDDAH), which are also inhibitors for the arginine deiminase; (2) the most potent inhibitors are based on indolylthiobarbituric acid (IC(50)=2-17 microM, PaDDAH), which were identified by virtual modelling; and (3) L-arginine analogs, whose best representative is N(omega)-(2-methoxyethyl)-L-arginine (IC(50)=22 microM, rat DDAH). Based on these known structures, we aimed to develop inhibitors for the human DDAH-1 with improved potency and better relative selectivity for DDAH-1 over NOS. Particularly, the binding pocket of the guanidine-moiety was investigated by screening differently substituted guanidines, amidines and isothioureas in order to collect information on possible binding modes in the active site. All substances were tested in a plate-reader format and HPLC assay and several potent inhibitors were identified with K(i)-values varying from 2 to 36 microM, with N(5)-(1-iminobut-3-enyl)-L-ornithine (L-VNIO) being the most potent inhibitor of the human DDAH-1 so far described. Besides these potent inhibitors alternate substrates for hDDAH-1 were identified as well.
最近的研究表明，抑制二甲基精氨酸二甲胺水解酶（DDAH）的活性可能是一种通过提高N（ω）-甲基化L-精氨酸（NMMA，ADMA）水平来间接影响一氧化氮（NO）生成的新策略。这种方法是治疗与NO浓度升高相关疾病的一种替代策略。迄今为止，已知三类强效抑制剂：（1）五氟苯基磺酸盐（IC50 = 16 - 58 μM，PaDDAH），其也是精氨酸脱亚氨酶的抑制剂；（2）最有效的抑制剂基于吲哚基硫代巴比妥酸（IC50 = 2 - 17 μM，PaDDAH），是通过虚拟建模鉴定出来的；（3）L-精氨酸类似物，其最佳代表是N（ω）-（2-甲氧基乙基）-L-精氨酸（IC50 = 22 μM，大鼠DDAH）。基于这些已知结构，我们旨在开发对人DDAH-1具有更高效力且对DDAH-1相对于一氧化氮合酶（NOS）具有更好相对选择性的抑制剂。特别是，通过筛选不同取代的胍、脒和异硫脲来研究胍部分的结合口袋，以便收集有关活性位点中可能结合模式的信息。所有物质均采用酶标仪形式和高效液相色谱法进行测试，并鉴定出几种强效抑制剂，其抑制常数（Ki）值在2至36 μM之间变化，其中N5-（1-亚氨基丁-3-烯基）-L-鸟氨酸（L-VNIO）是迄今为止所描述的人DDAH-1最有效的抑制剂。除了这些强效抑制剂外，还鉴定出了人DDAH-1的替代底物。
