What is the use of T4 PNK?

T4 PNK, or T4 Polynucleotide Kinase, is an enzyme that catalyzes the transfer of the gamma-phosphate of ATP to the 5'-hydroxyl terminus of DNA or RNA. It's used for 5' phosphorylation for ligation reactions, labeling the 5' ends of DNA or RNA, and removing 3' phosphate groups. Additionally, it's applied in various biotechnology procedures such as DNA sequencing, hybridization probes preparation, and more.