The Apoptosis Base Kit provides basic components for the quantitative determination of total p53, phospho-p53 (Ser15), PARP (cleaved), and Caspase-3 (cleaved) in human whole cell lysates. Caspase-3 is initially synthesized as a precursor protein but is activated by proteolytic cleavage of the N-terminus to produce the p20 and p17 cleavage (ASP175) products measured in this kit. PARP becomes inactive following cleavage (ASP214), however, the small cleavage product does retain its DNA-binding capabilities, blocking access to damaged DNA and inhibiting further DNA repair. Base kits generally include only MSD plates coated with the capture antibody, SULFO-TAG-labeled antibody, and MSD proprietary read buffer. (See product insert for a list of kit components). Base kits are most commonly used for high-throughput screening and assay development.