Heat-labile alkaline phosphatase from Antarctic bacteria: Rapid 5′ end-labeling of nucleic acids

A heat-labile alkaline phosphatase has been purified to near homogeneity from HK47, a bacterial strain isolated from Antarctic seawater. The active form of the enzyme has a molecular weight of 68,000 and is uniquely monomeric. The optimal temperature for the enzymatic activity is 25 degrees C. Complete and irreversible thermal inactivation of the enzyme occurs in 10 min at 55 degrees C. By using this heat-labile enzyme for dephosphorylation followed by a 10-min heat treatment, rapid end-labeling of nucleic acids by T4 polynucleotide kinase has been achieved.