Alkaline Phosphatase is an enzyme which catalyzes the hydrolysis of the phosphomonoesters of the 5' nucleotides. It is used to dephosphorylate (remove phosphate groups from) the 5' ends of DNA or RNA molecules, to facilitate 5' end-labeling with the 32P added back by T4 polynucleotide kinase; or to dephosphorylate the 5' ends of DNA molecules to prevent unwanted ligation reactions during cloning.