Klenow Fragment

Klenow Fragment is a proteolytic fragment derived from Escherichia coli DNA polymerase I. It retains the DNA polymerase activity and the 3'→5' exonuclease activity of the original enzyme, but lacks the 5'→3' exonuclease activity. Klenow Fragment is commonly used for DNA labeling by random priming, incorporating labeled nucleotides to generate DNA probes. It can also catalyze the formation of blunt ends from DNA fragments with 5' or 3' overhanging sticky ends. Additionally, Klenow Fragment is widely employed in synthesizing the second strand of cDNA, facilitating the construction of double-stranded cDNA libraries. Due to the absence of 5'→3' exonuclease activity, Klenow Fragment does not degrade template DNA during DNA synthesis, thus providing greater stability and accuracy in experimental procedures.