Alkaline phosphatase is a phosphomonoesterase, used to remove 5′-phosphate groups from nucleic acid molecules to prevent self-ligation of DNA fragments and vectors during recombinant DNA manipulations.

• Enzyme Commission Number: E.C. 3.1.3.1
• Isoelectric point (pI): 5,7 (Lit.)
• Free of endonuclease, exonuclease, and RNase activities

It is used in the laboratory to remove phosphate monoesters which prevents self-ligation. It is also used in the dairy industry to confirm pasturisation of milk. It is commonly conjugated to antibodies and used in immunoblotting, ELISA's, and other antibody based detection assays.

Activators: Zn, Mg²⁺, Ca²⁺, Tris buffer, diethanolamine
Inhibitors: Acidification to pH 4,5 reversibly inactives the enzyme; inorganic phosphate, chelating agents such as EDTA

Unit definition: That amount of enzyme causing the hydrolysis of one micromole of p-nitrophenyl phosphate per minute at 25 °C and pH 9,6.