The larger of two fragments obtained by the enzymatic cleavage of the DNA polymerase I of E. coli. The drawing below shows that the Klenow fragment lacks 5′ → 3′ exonuclease activity. Because of this, the Klenow fragment has various uses in genetic engineering techniques and in DNA sequencing methodologies where the 5′ → 3′ exonuclease activity of intact DNA polymerase I is disadvantageous. See Chronology, 1971, Klenow; DNA polymerase.
Subjects: Chemistry — Genetics and Genomics.