Pfu DNA ligase is a recombinant enzyme derived from Pyrococcus furiosus hyperthermophilic marine archaebacterium that catalyses linkage of adjacent 5'-phosphate and 3'-hydroxy ends of double-stranded DNA at 45 to 80 °C, with a temperature optimum near 70 °C for nick-sealing reactions.

• Highly thermostable, with half-life of over 60 minutes at 95 °C
• Increases reliability of LCR by permitting higher melt temperatures
• Eliminates LCR template-predenaturation step, less enzyme required for LCR

It has higher ligation specificity and lower background than T^th DNA ligase.