Klenow Fragment

Catalog No. 1091

Availability: In stock

Price From: $52.00

Quick Overview

Large fragment of E. coli DNA Polymerase I enzyme which retains both the polymerase and the proofreading 3'→5' exonuclease activities of Polymerase I

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Price From: $52.00



Escherichia coli


  • Lacks 5'→3' exonuclease activity (1)
  • Ultrapure recombinant enzyme

Fragment Applications

  • Used for Sanger dideoxy sequencing (2)
  • Suitable for second strand cDNA synthesis (3)
  • Used for 3'-end labeling and filling in 5'-protruding sticky ends (4)

Reagents Included

10X DNA Polymerase I (Klenow) Reaction Buffer

Unit Definition

One unit is the amount of enzyme required to incorporate 10 nmoles of total nucleotide into acid insoluble form in 30 minutes at 37°C

Heat Inactivation

75ºC for 15 minutes


5 - 10 units/µl

Storage Buffer

50 mM potassium phosphate (pH 7.0) 
0.25 mM dithiothreitol 
50% (v/v) glycerol

Assay Conditions

67 mM potassium phosphate (pH 7.4)
6.7 mM MgCl2
1 mM dithiothreitol
0.033 mM of each dCTP, dGTP, dTTP and [α-32P]dATP
4.5 µg activated DNA 
Incubation for 30 minutes at 37ºC in a total reaction volume of 
100 µl

Quality Control

All preparations are assayed for contaminating endonuclease and 5'-exonuclease activities. Typical preparations are greater than 95% pure, as judged by SDS polyacrylamide gel electrophoresis

Storage Conditions

Store at -20°C
Product shipped on dry ice


Certificate of Analysis PDF -Current Lot


1. Joyce, C.M. and Grindley, N.D., Proc. Natl. Acad. Sci. USA 80, 1830-1834. 1983
2. Sanger, F., Nicklen, S. and Coulson, A.R. (1977) Proc. Natl. Acad. Sci. USA 74, 5463-5467
3. Houdebine, L.M. (1976) Nucleic Acids Res. 3, 615-630
4. Sambrook, J., Fritsch, E.F., and Maniatis, T. (1989) Mol. Cloning: A Laboratory Manual, Second Ed. pp. 5.34, 5,4-5.43
5. Richardson, C.C.. Schildkraut, C.L., Aposhian, H.V. and Kornberg, A., J. Biol. Chem. 239, 222-232. 1964