A capillary electrophoresis (CE) method was developed for the screening of 5′-methylthioadenosine nucleosidase (MTAN) inhibitors in traditional Chinese drugs and small molecular compounds. In this method, reaction occurred at the capillary inlet during a predetermined waiting period, followed by electrophoretic separation of the reaction substrates and products. Parameters affecting separation efficiency and enzyme activity were evaluated systematically. The optimized conditions were as follows: 30 mM phosphate (pH 3.0) running buffer, 25 kV applied voltage, 20 mM HEPES (pH 6.0) reaction buffer, and 4 min incubation time. Under the optimized conditions, the Michaelis–Menten constant ( K m ) of MTAN was 3.44 μM, which agreed with the documented data. The proposed method was successfully applied for MTAN inhibitor screening from 21 natural extracts and 8 small molecular compounds. The results demonstrated the practical applicability of the at-inlet reaction-based CE method in screening of MTAN inhibitors from natural products and small molecular compounds.

中文翻译：

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毛细管入口酶促反应毛细管电泳法筛选中药及小分子化合物中5′-甲基硫腺苷酶抑制剂

毛细管电泳 (CE) 方法被开发用于筛选中药和小分子化合物中的 5'-甲基硫腺苷核苷酶 (MTAN) 抑制剂。在该方法中，反应在预定的等待期内在毛细管入口处发生，然后反应底物和产物的电泳分离。系统地评估了影响分离效率和酶活性的参数。优化条件如下：30 mM 磷酸盐 (pH 3.0) 运行缓冲液、25 kV 施加电压、20 mM HEPES (pH 6.0) 反应缓冲液和 4 分钟孵育时间。在优化条件下，MTAN 的 Michaelis-Menten 常数 (K m ) 为 3.44 μM，与记录数据一致。该方法已成功应用于 21 种天然提取物和 8 种小分子化合物的 MTAN 抑制剂筛选。结果证明了基于入口反应的 CE 方法在从天然产物和小分子化合物中筛选 MTAN 抑制剂的实际适用性。