T4 DNA polymerase.
T4 DNA polymerase (EC catalyzes the 5´-3´ synthesis of DNA from a primed ssDNA template. The enzyme can not utilize nicked DNA as a substrate, since it lacks 5´-3´ exonuclease activity. The enzyme has a highly active 3´-5´ proofreading exonuclease activity, 200-fold higher than that of Klenow fragment.
Unit definition

One unit of the enzyme catalyzes the incorporation of 10 nmol of total nucleotide into an acid insoluble form in 30 min at 37°C.

Reaction buffer
M (x10)
Reaction conditions
The enzyme will function in most buffers for restriction endonucleases, but has pH optimum 8.0-9.0. The reaction can be performed at 37°C or at room temperature, but incubation at 12°C maximizes the polymerase activity over that of the exonuclease.
Store at -20°C.
removal of 3´ overhang for blunt-end formation; ”gap-filling“ during site-directed mutagenesis; single strand deletion subcloning; DNA labeling using replacement synthesis.

Quality control

activity, SDS-PAGE purity, absence of endonuclease activity.


1. Englund, P. (1971) J. Biol. Chem. 246, 3269-3276.

Catalog #



Pack size

500 U

1000 U



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