Acid Phosphatase Colorimetric Assay Kit

Acid phosphatase (ACP) is an acid hydrolase abundant in lysosomes and widely used as a lysosome-specific biomarker. It is divided into tartrate-sensitive (lysosome‑originated) and fluoride-sensitive isoforms (found in erythrocytes and macrophages). ACP activity is low in normal serum, plasma and urine, but high in semen. Altered ACP activity occurs under pathological conditions such as prostate cancer bone metastasis, Gaucher disease and hemolytic disorders, making it a valuable biochemical marker for lysosomal function, cellular injury and tumor progression in cell biology and reproductive-related research.

This colorimetric kit uses p-nitrophenyl phosphate (pNPP) as substrate. Under acidic conditions, ACP hydrolyzes pNPP into p-nitrophenol (pNP). After alkalization, yellow-colored pNP is quantified by absorbance at 405 nm, with signal intensity proportional to ACP activity. The assay requires minimal sample pretreatment and is compatible with cells, tissues, plasma, serum and urine samples.

Figure 1. The p-Nitrophenol (pNP) standard curve.