T4 DNA ligase

T4 DNA Ligase catalyzes the formation of a phosphodiester bond between 5′-phosphate and 3‘-hydroxyl ends in double strand DNA or RNA with blunt or cohesive-end termini.

long time at -20°C

Contain with Tris-HCl, MgCl₂, DTT, ATP

20 mM Tris-HCl (pH 7.5), 1mM DTT, 50mM KCl, 0.1mM EDTA and 50% glycerol

By heating at 65°C for 10mins

0.01 Weiss unit is defined as the amount of enzyme  required to catalyze the ligation of greater than 95% of the Hind III fragments of 1mg of Lambda DNA at 16°C in 20 minutes.

Joining double-stranded DNA with cohesive or blunt

termini and 3’T-A overhangs.

If the reaction is blunt end or T-A ligation must have more units of T4 DNA ligase. T4 DNA ligase is strongly inhibited by NaCl or KCl if the concentration exceeds 200mM.