DAz-1 is a cell-permeable sulfonic acid probe that directly detects sulfonic acid-modified proteins in living cells [1].

Detection methods for DAz-1 sulfonic acid under various conditions [1]: Prepare a 10 μM protein solution, 50 μg of cell lysate, or 200 μg of protein lysate. Add 50 or 100 μM H2O2 and incubate at room temperature for 20 minutes; then, introduce 1 mM Daz-1 or 5% (v/v) DMSO, continuing the reaction at room temperature for 15 minutes. Quench the reaction using 5 mM DTT, and remove excess reagents via gel filtration. Separate proteins using 4-12% SDS-PAGE, transfer them to a PVDF membrane, and detect with HRP-Streptavidin WB.