Klenow Fragment (3´→ 5´ exo-) is an N-terminal truncation of DNA Polymerase I which retains polymerase activity, but has lost the 5´→ 3´ exonuclease (nick-translation) activity, and proofreading (3′→ 5′) exonuclease activity due to two amino acids mutations (D355A, E357A).

• Random-primed DNA labeling
• DNA sequencing by the Sanger dideoxy method
• Second strand cDNA synthesis
• Labeling by fill-in 5'-overhangs of dsDNA
• Strand displacement amplification (SDA)

One unit is defined as the amount of enzyme that will incorporate 10 nmol of dNTP into acid insoluble material in 30 minutes at 37°C.

• Klenow Fragment exo-: 5,000 U/ml in 25 mM Tris-HCl, 1 mM DTT, 0.1 mM EDTA, 50% Glycerol, pH 7.4 @ 25°C
• 10X Reaction Buffer: 500 mM NaCl, 100 mM Tris-HCl, 100 mM MgCl₂, 10 mM DTT, pH 7.9 @ 25°C

• The absence of endo- and exodeoxyribonucleases confirmed by appropriate quality tests.
• Functionally tested in random-primed DNA labeling.

-20 °C