Activation of caspases plays a central role in apoptosis. The CaspGLOW™ Fluorescein Caspase-12 Staining Kit provides a convenient means for sensitive detection of activated caspase-12 in living cells. The assay utilizes the caspase-12 inhibitor, ATAD-FMK, conjugated to FITC (FITC-ATAD-FMK) as a marker. FITC-ATAD-FMK is cell permeable, nontoxic, and irreversibly binds to activated caspase-12 in apoptotic cells.