ExpressLink™ T4 DNA Ligase catalyzes the ligation of blunt- or cohesive-end DNA fragments in only 5 minutes at room temperature (25° C), and PCR fragments with “A" overhangs in 15 minutes, also at 25° C. Single-stranded nucleic acids are not substrates for this enzyme.

T4 DNA ligase catalyzes the formation of phosphodiester bonds between double-stranded DNA strands with 3´ hydroxyl and 5´ phosphate termini in the presence of ATP. ExpressLink™ T4 DNA Ligase formulation is optimized for faster reaction times and more convenient incubation temperature than our other T4 DNA Ligase formulations.

Source: E. coli expressing a T4 DNA ligase gene.

Important benefits of ExpressLink™ T4 DNA Ligase:

• Fast, 5 minute ligation of blunt- or cohesive-end DNA fragments.
• Ligation of PCR fragments with “A" overhangs in 15 minutes.
• Convenient 25° C reaction temperature eliminates the need for a water bath or temperature block.
• Ideal for cloning DNA into vectors, recircularization of linear DNA, library construction, TA cloning, and linker ligation.
• Superior exonuclease quality control assay for exonuclease-free ligations

See the Difference the Cleanest Ligase Makes

We apply the most stringent test available for exonuclease contamination to every lot of ExpressLink™ T4 DNA Ligase. The superior sensitivity of our assay will detect much lower active exonuclease concentrations than assays used by other manufacturers. As a result, we offer one of the best ligase products on the market (see figure). You can be confident of achieving the highest quality data in your important experiments with ExpressLink™ T4 DNA Ligase.

Performance and Quality Testing: Endodeoxyribonuclease, 3´ and 5´ exodeoxyribonuclease assays; ligation efficiency tested.

Unit Definition: One unit catalyzes the exchange of 1 nmol 32P-labeled pyrophosphate into ATP in 20 min. at 37° C (One unit is equal to approximately 300 cohesive-end ligation units).

Unit Reaction Conditions: 66 mM Tris-HCl (pH 7.6), 6.6 mM MgCl2, 10 mM DTT, 66 µM ATP, 3.3 µM 32P-labeled pyrophosphate, and ExpressLink™ T4 DNA Ligase (Cat. No. A13726) in 0.1 ml for 20 min. at 37° C.