Acid Phosphatase

Acid phosphatases are hydrolases that release inorganic phosphate from phosphomonoesters at acidic pH, functioning in lysosomes, the cytosol, and secretory compartments. Prominent human members include lysosomal acid phosphatase (ACP2), cytosolic low-molecular-weight acid phosphatase (ACP1), tartrate-resistant acid phosphatase (ACP5) produced by osteoclasts and activated macrophages as a marker of bone resorption and inflammation, and prostatic acid phosphatase (ACPP), a prostate-secreted enzyme long used as a serum biomarker in prostate cancer before the advent of prostate-specific antigen. Serum and tissue acid phosphatase measurements therefore remain informative in bone, hematologic, and prostatic disorders.