Ambion® T4 Polynucleotide Kinase (PNK, E.C. 2.7.1.78) catalyzes the transfer of the terminal phosphate of ATP to 5' hydroxyl termini of DNA or RNA. T4 PNK is recommended for 5' end-labeling of oligonucleotides and polynucleotides. It also has a 3' phosphatase activity. One tube containing 500 U (10 U/ µL) is provided. T4 Polynucleotide Kinase is rigorously tested for contaminating nonspecific endonuclease, exonuclease, RNase and protease activity, and for functionality in a KinaseMax™ Kit (SKU# AM1520). Reaction buffer is not included with this enzyme.

Unit Definition:
One unit is defined as the amount of enzyme catalyzing the production of 1 nmol of phosphate to the 5'-OH end of an oligonucleotide from [gamma-³²P]ATP in 30 min at 37°C.