4-Nitrophenyl phosphate (disodium hexahydrate)

4-Nitrophenyl phosphate (p-nitrophenyl phosphate) disodium hexahydrate is widely used as a small molecule phosphotyrosine-like substrate in activity assays for protein tyrosine phosphatases. 4-Nitrophenyl phosphate disodium hexahydrate is a colorless substrate that upon hydrolysis is converted to a yellow 4-nitrophenolate ion that can be monitored by absorbance at 405 nm[1].