Figure 3. (A) SDS-PAGE experiments of labeling protein Xyn (original xylanase), N2C (fused protein with peptide tag after purification) and Crude N2C (fused protein with peptide tag) with FL-DT . (B) Relative fluorescence intensity of responses of FL-DT (1 μM) to various recombinant protein NOC, Xyn, N2C and N2C (0.1 mg/mL) after reaction with sulfhydryl masking agent NMM (100 μM), (n=3, error bars represent SD). (C) Standard curve of Xylose concentration (0.1-0.34 mg/mL) and OD (optical density) at 540 nm, (n=3, error bars represent SD). (D) Enzyme activity assay of pure protein Xyn, N2C, and N2C-FL-DT adducts, the concentration of proteins is 0.5 mg/mL, (n=3, error bars represent SD).