4-Nitrophenyl phosphate (ditromethamine)

4-Nitrophenyl phosphate ditromethamine is an enzyme substrate commonly used in biochemical assays to measure the activity of various phosphatases, including alkaline phosphatase. 4-Nitrophenylphosphate has unique chemical properties that allow it to be hydrolyzed by phosphatases, releasing a yellow product that can be detected spectrophotometrically.