T4 Polynucleotide Kinase

Phosphorylating the 5' ends of DNA and RNA is a recurring need in NGS library preparation and broader molecular biology research. QIAGEN's T4 Polynucleotide Kinase delivers that capability as a versatile enzyme preparation that catalyzes the transfer of a gamma-phosphate from ATP to the 5'-hydroxyl terminus of single- and double-stranded polynucleotides, while also exhibiting 3'-phosphatase activity that removes 3' phosphate groups. This dual functionality is valuable when preparing fragments ahead of adapter ligation, repairing damaged termini, and end-labeling oligonucleotides with radiolabeled or fluorescent ATP analogs.

The enzyme is supplied with a 10x reaction buffer optimized for kinase activity. Typical reactions run in 50 uL volumes with 1-10 units of enzyme and approximately 1 mM ATP. Storage at -20°C preserves activity through multiple freeze-thaw cycles when small working aliquots are kept on ice during use, and the reagent ships on refrigerated gel packs to maintain cold-chain integrity.

Common applications include blunt-end ligation, phosphorylation of adapters and linkers during sequencing library prep, removal of 3' phosphates prior to cloning or sequencing, and 5' end-labeling for downstream detection assays.