Figure 2.

(A) Optical characterization of fluorescence emission of FAP-MB-5 and MB in MeOH. (B) Fluorescence intensity of FAP-MB-5 (200 μM) pre-incubated with or without talabostat (100 μM) for 1 h towards various concentration of rhFAPα (0.225, 0.3, 0.375, 0.45 μg/mL) over time. Excitation: 630 nm. (C) UV-vis absorption spectra change of FAP-MB-5 (500 μM) towards various concentration of rhFAPα (0.225, 0.3, 0.375, 0.45 μg/mL). As inhibition group, rhFAPα (0.45 μg/mL) was pre-incubated with talabostat (100 μM) for 1 h, and then incubated with FAP-MB-5. (D) HPLC chromatogram of rhFAPα-mediated hydrolysis of FAP-MB-5 over time. As inhibition group, rhFAPα was pre-incubated with talabostat (100 μM) for 1 h. (E) Fluorescence response of FAP-MB-5 (200 μM) treated with the indicated protein (0.45 μg/mL unless otherwise specified), metal iron (50 μM) and other analytes (50 μM) for 1 h. 1, control; 2, Na⁺; 3, Mg²⁺; 4, Fe³⁺; 5, H₂O₂; 6, GSH; 7, ascorbic acid; 8, Gly; 9, Pro; 10, Cys; 11, BSA; 12, esterase; 13, collagenase; 14, Legumain; 15, APN; 16, DPPIV; 17, rhFAPα (0.225 μg/mL) pre-incubated with talabostat; 18, rhFAPα (0.225 μg/mL). (F) DPBF attenuation by ¹O₂ generation with different treatments in MeOH at 415 nm. (G) ESR spectra of different reaction systems with TEMP as the spin trap. (H) Docking analysis of the interactions of FAP-MB-5 with FAPα. (I) Detailed interactions between FAP-MB-5 and FAPα in a three-dimensional view. (+) and (-) refer to the treatment with or without irradiation, respectively. Results are described as mean ± SD, n = 3.