DNA Polymerase I Large (Klenow) Fragment

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