Fig. 1: Design and synthesis of biotin-phenol (BP) derivatives with high reactivity.

a Design of different BP derivatives with substituents at para-position (red), ortho-position (blue), and with aromatic amine structures (orange). b Scheme of proximity labeling catalyzed by peroxidases in living cells and in vitro. c Consumption rate of BP derivatives in the presence of 10 nM HRP and 500 μM H₂O₂ for 20 min. Each dot represents the indicated data of one independent experiment. Data are presented as mean values ± standard divations (s.d.; n = 3 independent biological experiments). d Streptavidin western blot analysis of labeling activity of BP1, BP5, BP10, and BN2 in living HeLa cells with stably expressed APEX2-FLAG-GRB2 fusion protein (n = 3 independent biological experiments). After incubating the cells with probes for 30 min, 500 µM of H₂O₂ was added for 1 min reaction. Quantification was presented in Supplementary Fig. 12a. e, f Comparison between BP1 and BP5 reactivity with or without tyrosine when incubated together. Data are presented as mean values ± s.d. Error bars in c, e, and f represent s.d. as quantified by LC-MS (n = 3 independent biological experiments). Source data are provided as a Source Data file.