DNA Polymerase I Large (Klenow) Fragment is a 68kDa C-terminal fragment of E. coli DNA Polymerase I that lacks the 5´→3´ exonuclease activity of intact DNA polymerase I but retains its 5´→3´ polymerase, 3´→5´ exonuclease and strand displacement activities.

• Use in a variety of molecular applications
• Heat-inactivate by heating at 75 °C for 10 minutes
• Active in many Promega 1X restriction enzyme buffers
• Supplied at a concentration of 5 U/μl

The 5´→3´ polymerase activity of Klenow fragment can be used to fill in 5´-protruding ends with unlabeled or labeled dNTPs, to sequence single- or double-stranded DNA templates, for in vitro mutagenesis using synthetic oligonucleotides, for cDNA second-strand synthesis and to generate single-stranded DNA probes. The 3´→5´ exonuclease activity can be used to generate blunt ends from a 3´-overhang.

Unit definition: One unit is defined as the amount of enzyme required to catalyse the incorporation of 10 nmol of deoxynucleotide into acid-precipitable material in 30 minutes at 37 °C.