Figure 6.

(A) Labeling of protein sulfenic acids in live cells using DCP-Bio1 (1, 0.1, and 0.025 mM) and 4 (0.1, 0.05, and 0.025 mM). SCC-61 cells were incubated for 30 min (37 °C, 5% CO₂) in the presence of each probe (final concentration of DMSO was 0.2%), washed twice with cold PBS, and then lysed with mRIPA buffer in the absence of probe. (B) ESI-TOF mass spectra for the labeling of C165A AhpC-SOH (20 μM, top panel) with 1 (20 μM) and dimedone (5 mM) at 15 min in 25 mM Tris pH 7.0 (rt, bottom panel).