The Phosphate Sensor is a highly sensitive reagent for the detection of inorganic phosphate, either in real-time kinetic or end-point mode. This product is a purified form of recombinant E. coli phosphate-binding protein labeled with the fluorophore MDCC, which is sensitive to changes in its environment. Binding of inorganic phosphate by Phosphate Sensor is rapid and tight (Kd ∼ 0.1 μM), resulting in a large increase in fluorescence. The Phosphate Sensor detects phosphate in the high-nanomolar to low-micromolar range, which is 100-fold more sensitive than malachite green. This reagent provides you with a sensitive assay for detecting enzymes that produce inorganic phosphate either directly or indirectly through coupled reactions, such as phosphatases, ATPases, GTPases, and phosphodiesterases.