Ready-to-use fluorometric substrate for caspases that recognize the amino acid sequence ATAD. Caspase activity can be quantified by fluorescent detection of free AFC after cleaved from the peptide substrate ATAD-AFC at Ex/Em = 400/505 nm using a fluorometer or a fluorescence plate reader. Alternatively, a shift in fluorescence from blue to green upon cleavage can be visualized using a hand-held long-UV lamp. The ready-to-use caspase substrate provides an economic alternative for researchers who perform large amount of caspase assays. Cell Lysis Buffer (Cat.# 1067-100), 2X Reaction Buffer (Cat.# 1068-20), DTT (Cat.# 1201-1), and other reagents used for caspase activity assays are also available separately.