Dyes and Fluorophores 

FDP (fluorescein diphosphate, tetraammonium salt, high purity) is the most sensitive fluorogenic alkaline phosphatase substrate. It is also an excellent substrate for protein tyrosine phosphatase (PTPase) and thus the substrate of choice in the high throughput screening (HTS) for PTPase inhibitor. FDP itself is colorless, but the end product of the enzymatic reaction is the green fluorescent dye fluorescein.

• λ_Ex/λ_Em = 490/514 nm (end product)
• ε = 90,000 (end product)
• Off-white solid soluble in water
• Store at -20°C and protect from light, especially in solution
• C₂₀H₂₆N₄O₁₁P₂
• MW: 560.39