2-Aminopurine Dihydrochloride is a purine analog that acts as a protein kinase inhibitor. The compound is a mutagen that can incorporate into DNA and has been used as a fluorescent probe. Studies indicate that it can alter checkpoints in the phases of the cell cycle, in particular alter cells to enter mitosis in S-phase arrested cells incorrectly and override a γ radiation induced G|2|block. Additionally, it has been demonstrated that 2-Aminopurine Dihydrochloride inhibits PITSLREβ1 protein kinase activity, and that it can alter the structure and dynamics of DNA. 2-Aminopurine Dihydrochloride does not effect the protein kinase activity of p34cdc2. 2-Aminopurine Dihydrochloride is an inhibitor of PKR.