Department of Biochemistry and Biophysics, Arrhenius Laboratories, Stockholm University, SE-10691, Stockholm, Sweden.
Sci Rep. 2021 Oct 21;11(1):20765. doi: 10.1038/s41598-021-00327-1.
Nitric oxide (NO) plays a prominent physiological role as a low-molecular-mass signal molecule involved in diverse biological functions. Great attention has been directed to pharmacologically modulating the release of NO for various therapeutic applications. We have focused on O-(2,4-dinitrophenyl) 1-[(4-ethoxycarbonyl)piperazin-1-yl]diazen-1-ium-1,2-diolate (JS-K) as an example of diazeniumdiolate prodrugs with potential for cancer chemotherapy. JS-K is reportedly activated by glutathione conjugation by glutathione transferase (GST), but the scope of activities among the numerous members of the GSTome is unknown. We demonstrate that all human GSTs tested except GST T1-1 are active with JS-K as a substrate, but their specific activities are notably spanning a > 100-fold range. The most effective enzyme was the mu class member GST M2-2 with a specific activity of 273 ± 5 µmol min mg and the kinetic parameters Km 63 µM, k 353 s, k/Km 6 × 10 M s. The abundance of the GSTs as an ensemble and their high catalytic efficiency indicate that release of NO occurs rapidly in normal tissues such that this influence must be considered in clarification of the tumor-killing effect of JS-K.
一氧化氮（NO）作为一种参与多种生物功能的低分子量信号分子，在生理学中起着重要作用。人们非常关注通过药理学调节 NO 的释放，以用于各种治疗应用。我们以 O-(2,4-二硝基苯基)-1-[(4-乙氧羰基)哌嗪-1-基]二氮烯-1,2-二醇盐（JS-K）为例，研究了具有癌症化疗潜力的二氮烯二醇前药。据报道，JS-K 通过谷胱甘肽转移酶（GST）的谷胱甘肽缀合而被激活，但 GSTome 中众多成员的活性范围尚不清楚。我们证明，除 GST T1-1 外，所有测试的人 GST 均能以 JS-K 作为底物发挥作用，但它们的比活性显著跨越了 100 倍的范围。最有效的酶是μ类成员 GST M2-2，其比活性为 273±5 μmol min mg，动力学参数 Km 为 63 μM，k 为 353 s，k/Km 为 6×10 M s。GST 作为一个整体的丰度及其高催化效率表明，NO 的释放会在正常组织中迅速发生，因此在阐明 JS-K 的肿瘤杀伤作用时必须考虑到这一影响。
