However, in the case of enzyme immobilization, the reduction of initial enzyme activity is a routine drawback and nanozymes development can be considered as a right solution for overcoming this drawback . In fact, the deep development of nanoscience leads to synthesis of new nanomaterials with unique catalytic activity , unique optical properties , high active area , antibacterial properties , and high biocompatibility . Some of new nanomaterials with unique catalytic activity show enzyme-like activity with high stability, leading to their application in different fields, in developing sensing assays of amino acids, glutathione (GSH), tetracycline, metal cations, glucose, H2O2, explosives, malathion , and new SARS-CoV-2 as after the first report of COVID-19 . However, the researches focusing on the inhibitory effect of inhibitors on nanozymes activity are limited to a few reports. Herein, the effect of the glutathione molecules (a possible inhibitor) on the peroxidase-like activity of the enzymelike N-doped carbon dots was evaluated. To do this investigation, the enzyme-like activity of N-doped carbon dots was evaluated toward peroxidase-mediated oxidation of TMB as a common peroxidase substrate, revealing high intrinsic peroxidase-like activity of N-doped carbon dots. However, the intrinsic peroxidase-like activity of the N-doped carbon dot was significantly inhibited by the introduction of the glutathione molecules in the reaction media. Hence, the inhibitory effect of glutathione molecules on their nanozymatic activity was evaluated as a function of enzyme-like residual activity in the presence of glutathione molecules. The results reveal that the relative activity of nanozymes was inhibited by increasing the glutathione concentration in the reaction media.