6,8-difluoro-4-methylumbelliferyl phosphate

Fig. 2 Common generic FTP substrates. p-Nitrophenylphosphate (pNPP), 6,8-difluoro-4-methylumbelliferyl phosphate (DiFMUP), and 0-methyl-fluorescein phosphate (OMFP)...

Applied are fluorogenic compounds such as 6,8-difluoro-4-methylumbelliferyl phosphate (DiFMUP) or compounds changing the absorption spectra after dephosphorylation, such phospho-tyrosine, paro-nitrophenol phosphate (pNPP) or 3-0-methylfluorescein phosphate (OMFP) [22, 26] (Figure 3). In a phosphatase inhibition assay, the phosphatase is first incubated with the inhibitor and then the phosphatase activity assay is carried out. Reduced activity due to inhibition is measured by one of the above-mentioned assay types, which are chosen depending on the phosphatase. A parameter often obtained in inhibition assays is the inhibitor concentration 50 (ICjq) (inhibition constant), which is the concentration where 50% of the enzyme is inhibited. 

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