DNA-Dependent Protein Kinase (DNA-PK) phosphorylates several DNA-binding substrates in vitro, including the tumor suppressor protein p53, the SV40 large T antigen and several transcription factors. DNA-PK is thought to play a role in controlling gene regulation and cell growth.
DNA-PK is isolated from HeLa nuclear extracts as a complex consisting of a 400kDa catalytic subunit and a 155kDa heterodimeric DNA-binding component named Ku, which itself consists of subunits of approximately 85kDa and 70kDa.
Storage Buffer: 25mM HEPES (pH 7.5), 50mM KCl, 0.2mM EDTA, 10mM MgCl2, 1mM DTT, 10% glycerol.
Unit Definition: One unit is defined as the amount of enzyme required to transfer 1pmol of phosphate to DNA-Dependent Protein Kinase Peptide Substrate in 1 minute at 30°C.