ADP is a product of ATP dephosphorylation and it can be rephosphorylated to ATP. Dephosphorylation and rephosphorylation occur via various phosphorylases and kinases. ADP is stored in platelets and can be released to interact with variety of purinergic receptors. ADP levels regulate several enzymes involved in intermediary metabolism. ADP conversion to ATP primarily occurs within the mitochondrion and chloroplast although several such processes occur in the cytoplasm. Conventionally, ADP levels are measured by luciferase/luciferin mediated assays after ADP is converted to ATP. However, the luciferase system is unstable and luminescence equipment is not generally available in most laboratories. BioVision ADP Assay kit II is suitable for meas