2-Chloroadenosine 5-triphosphate (2-chloro ATP), an analog of ATP and adenine nucleotide, functions as an antagonist of the purinergic P2Y1 receptor, inhibiting ADP-induced intracellular calcium mobilization in Jurkat cells with a Ki value of 2.3 µM. Additionally, 2-chloro ATP acts as an agonist of purinergic P2X receptors, demonstrated by inducing inward currents in HEK293 cells expressing either human bladder smooth muscle or rat PC12 receptor forms, with EC50 values of 0.5 and 2.5 µM, respectively. It also triggers relaxation in precontracted isolated guinea pig taenia caeci strips in a concentration-dependent fashion. Furthermore, 2-chloro ATP has been employed in research to investigate the substrate specificity of cyclic nucleotide-dependent protein kinases, including protein kinase A (PKA) and PKG.