Screening for NDM-1 Enzyme Inhibitors

The assay was conducted according to Liao et al.’s method^{20 (link)} with minor modifications. To find NDM-1 inhibitors, we selected 75 natural compounds as screening compounds (Table S2). Assays were read in 96-well plates at an absorbance of 492 nm using a microplate reader (Tecan Austria GmbH, Grödig, Austria) at room temperature. Positive controls were performed in the presence of enzyme and in the absence of inhibitors, whereas negative controls were performed in the absence of enzyme. Residual activity = A−A₀/A₁₀₀−A₀ × 100%, where A represents the absorbance of inhibitor groups at 492 nm, and A₀ and A₁₀₀ represent 0% and 100% activity as determined in the negative controls and positive controls, respectively.