Invitrogen™ ExpressLink™ T4 DNA Ligase

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.

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. 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 1nmol 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: 66mM Tris-HCl (pH 7.6), 6.6mM MgCl₂, 10mM DTT, 66μM ATP, 3.3μM ³²P-labeled pyrophosphate, and ExpressLink™ T4 DNA Ligase in 0.1mL for 20 min. at 37°C.

• 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

ExpressLink™ T4 DNA Ligase is unstable when kept on ice for long periods. It is recommended that the enzyme be kept at –20°C until within 5–10 minutes of use and returned immediately to –20°C after use.