LIFE SCIENCE

Detailed explanation-1: -The Klenow fragment of DNA polymerase I is a proteolytic fragment obtained by the treatment of DNA polymerase I with subtilisin. The fragment still has the polymerase and 3’-5’ exonuclease activity, but lacks the 5’-3’ exonuclease activity of the holoenzyme (1).

Detailed explanation-2: -The Klenow fragment is a large protein fragment produced when DNA polymerase I from E. coli is enzymatically cleaved by the protease subtilisin.

Detailed explanation-3: -DNA Polymerase I, Large (Klenow) Fragment is a DNA polymerase enzyme that lacks the 5’ to 3’ exonuclease activity of intact DNA Polymerase I, but does exhibit the 5’ to 3’ DNA polymerase and 3’ to 5’ exonuclease activities.

Detailed explanation-4: -The 3’–>5’ exonuclease activity intrinsic to several DNA polymerases plays a primary role in genetic stability; it acts as a first line of defense in correcting DNA polymerase errors. A mismatched basepair at the primer terminus is the preferred substrate for the exonuclease activity over a correct basepair.