乳酸脱氢酶(LDH),无氧糖酵解的关键酶,在肿瘤细胞的能量代谢中起着举足轻重的作用,将其定位为有希望的肿瘤治疗靶点。芦丁,一种植物类黄酮,提供抗氧化剂等好处,抗凋亡,和抗肿瘤作用。本研究采用多种实验从结合角度研究芦丁对LDH的抑制机制。结果显示,芦丁在LDH的辅酶结合位点发生自发结合,导致形成由疏水作用力驱动的稳定二元复合物,氢键也显著有助于维持LDH-芦丁复合物的稳定性。LDH-芦丁体系在298K时的结合常数(Ka)为2.692±0.015×104M-1。芦丁诱导LDH二级结构构象的改变,以α-螺旋减少和反平行和平行β-折叠增加为特征,和β转。芦丁增强辅酶与LDH结合的稳定性,这可能会阻碍辅酶之间的转化过程。具体来说,LDH活性位点环中的Arg98在结合过程中提供了必需的结合能贡献。这些结果可能解释了芦丁对LDH催化活性的剂量依赖性抑制。有趣的是,食品添加剂抗坏血酸和四氢姜黄素均可降低LDH与芦丁的结合稳定性。同时,这些食品添加剂对芦丁与LDH的结合没有产生积极的协同作用或拮抗作用。总的来说,这项研究可以为芦丁的治疗潜力和药用价值提供独特的见解。
Lactate dehydrogenase (LDH), a crucial enzyme in anaerobic glycolysis, plays a pivotal role in the energy metabolism of tumor cells, positioning it as a promising target for tumor treatment. Rutin, a plant-based flavonoid, offers benefits like antioxidant, antiapoptotic, and antineoplastic effects. This study employed diverse experiments to investigate the inhibitory mechanism of rutin on LDH through a binding perspective. The outcomes revealed that rutin underwent spontaneous binding within the coenzyme binding site of LDH, leading to the formation of a stable binary complex driven by hydrophobic forces, with hydrogen bonds also contributing significantly to sustaining the stability of the LDH-rutin complex. The binding constant (Ka) for the LDH-rutin system was 2.692 ± 0.015 × 104 M-1 at 298 K. Furthermore, rutin induced the alterations in the secondary structure conformation of LDH, characterized by a decrease in α-helix and an increase in antiparallel and parallel β-sheet, and β-turn. Rutin augmented the stability of coenzyme binding to LDH, which could potentially hinder the conversion process among coenzymes. Specifically, Arg98 in the active site loop of LDH provided essential binding energy contribution in the binding process. These outcomes might explain the dose-dependent inhibition of the catalytic activity of LDH by rutin. Interestingly, both the food additives ascorbic acid and tetrahydrocurcumin could reduce the binding stability of LDH and rutin. Meanwhile, these food additives did not produce positive synergism or antagonism on the rutin binding to LDH. Overall, this research could offer a unique insight into the therapeutic potential and medicinal worth of rutin.