DNA Polymerase I, Large (Klenow) Fragment


    200 Units - $55.00 (Cat.# 3261 )

    1,000 Units - $230.00 (Cat.# 3262 )

Category: .


DNA Polymerase I, Large (Klenow) Fragment is a product of E. coli DNA Polymerase I which lacks the N-terminal 324 amino acids. This enzyme lacks the 5’→ 3′ exonuclease activity of intact DNA Polymerase I, but does exhibit the 5’→ 3′ DNA polymerase and 3’→ 5′ exonuclease activities

The physical purity of this enzyme is ≥99% as assessed by SDS-PAGE with Coomassie® blue staining (see figure below).


Product Source
E.coli cells carrying E. coli polA gene without its N-terminal exonuclease domain.


  • 3´-overhangs removal to form blunt ends (1).
  • 5´-overhangs fill-in to form blunt ends (1).
  • DNA library preparation for Next-generation sequencing (2).
  • 3′-end-labeling of DNA fragments using α-32P deoxynucleotides.
  • Second strand cDNA synthesis.
  • Single-stranded DNA probes generation.

Product Includes

  1. DNA Polymerase I, Large (Klenow) Fragment
  2. 10x Klenow Reaction Buffer

Storage Temperature
–20 °C

Storage Buffer

50 mM Tris-HCl (pH 7.5), 0.1 mM EDTA, 1 mM β-mercaptoethanol, 1 mM DTT, 50% (v/v) glycerol.

10x Klenow Reaction Buffer

500 mM Tris-HCl, 100 mM MgCl2, 50 mM dithiothreitol (DTT), pH 7.5 @ 25 °C.


Inactivated by heating at 75 °C for 20 min.

Quality Control Assays

DNA Polymerase I, Klenow Fragment is free from detectable endonuclease and RNase activities.


  1. Sambrook, J., Fritsch, E.F. and Maniatis, T. (1989). Molecular Cloning: A Laboratory Manual. (2nd ed.), 5.40-5.43. Cold Spring Harbor: Cold Spring Harbor Laboratory Press.
  2. Sanger, F. et al. (1977). Proc. Natl. Acad. Sci. USA. 74, 5463-5467.
  3. 3261 3262

Additional information


200 Units, 1,000 Units

DNA Polymerase I, Large (Klenow) Fragment

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