Alkaline Phosphatase Activity Colorimetric Assay Kit

Alkaline phosphatase (ALP) is a hydrolase that catalyzes the dephosphorylation of substrates under alkaline conditions. It is predominantly expressed in the liver, bile duct, bone, kidney, and placenta. ALP activity serves as a classical marker of successful reprogramming of induced pluripotent stem cells (iPSCs). In oncology, ALP activity correlates with the differentiation status of colorectal cancer cells. Clinically, aberrant serum ALP levels are associated with hepatobiliary disorders (e.g., malignant biliary obstruction, primary biliary cholangitis) and bone metabolic diseases, supporting its utility as a diagnostic adjunct.

This kit is based on the classic p-nitrophenyl phosphate (pNPP) colorimetric method. Under alkaline conditions, ALP catalyzes the hydrolysis of colorless pNPP to produce yellow p-nitrophenol (pNP), which has a maximum absorbance at 405 nm. The absorbance value is positively correlated with ALP activity. The assay is simple, sensitive, and broadly applicable to cells, tissues, serum, plasma, and other biological fluids, rendering it suitable for fundamental research and preclinical testing.

Figure 1. Typical pNP standard curve.