The effects of l-glycine (Gly) and l-glutamic acid (Glu) on oxidative damage induced by hydrogen peroxide (H₂O₂) in Pediococcus pentosaceus R1 were investigated. Gly and Glu significantly reduce the production of intracellular reactive oxygen species and the levels of malondialdehyde and carbonylated proteins and concomitantly increase ATP levels in P. pentosaceus R1 under H₂O₂-induced stress (P < 0.05). Transmission electron microscopy and atomic force microscopy of bacteria under H₂O₂-induced stress revealed that Gly and Glu suppress bacterial membrane deformation and cell damage. Gly exhibited stronger ferrous ion-chelating ability, whereas Glu has higher radical scavenging activities and reducing power (P < 0.05). The abilities of Gly and Glu to inhibit lipid peroxidation are comparable. Gly and Glu significantly enhance the activities of superoxide dismutase and glutathione peroxidase, respectively, and increase the total antioxidant capacity of bacteria (P < 0.05). These findings indicate that Gly and Glu alleviate H₂O₂-induced oxidative stress via direct antioxidant effects and increase the activities of bacterial antioxidant enzyme.

研究了l-甘氨酸(Gly)和l-谷氨酸(Glu)对过氧化氢(H ₂ O ₂ )诱导的戊糖片球菌R1氧化损伤的影响。在 H ₂ O ₂诱导的应激下，Gly 和 Glu 显着降低细胞内活性氧的产生以及丙二醛和羰基化蛋白的水平，并同时增加P. pentosaceus R1 的ATP 水平（P  < 0.05）。H ₂ O ₂下细菌的透射电子显微镜和原子力显微镜诱导应激表明 Gly 和 Glu 抑制细菌膜变形和细胞损伤。Gly 表现出更强的亚铁离子螯合能力，而 Glu 具有更高的自由基清除活性和还原能力（P  < 0.05）。Gly 和 Glu 抑制脂质过氧化的能力相当。Gly和Glu分别显着增强超氧化物歧化酶和谷胱甘肽过氧化物酶的活性，提高细菌的总抗氧化能力（P  < 0.05）。这些发现表明 Gly 和 Glu通过直接抗氧化作用减轻 H ₂ O ₂诱导的氧化应激并增加细菌抗氧化酶的活性。