Cayman’s Alkaline Phosphatase (ALP) Colorimetric Activity Assay Kit provides a convenient method of measuring ALP activity in serum, plasma, tissue samples, and cell lysates with a limit of detection of 0.5 U/L. Measurement of ALP activity is carried out by monitoring the dephosphorylation of the chromogenic substrate p-nitrophenyl phosphate (pNPP). In the first step, ALP dephosphorylates pNPP generating p-nitrophenol. In the second step, the phenolic hydroxyl group is deprotonated under alkaline conditions resulting in p-nitrophenolate, which yields an intense yellow color that can be measured using absorbance at 405 nm. Under circumstances in which ALP activity is rate limiting, the increase in absorbance at 405 nm is directly proportional to ALP activity in the sample.
Biochemical and cellular assays