LeGene Klenow(exo-) DNA Polymerase is purified from E.coli. expressing a cloned Large Fragment of DNA polymerase 1. It exhibits 5’->3’ polymerase activity but lacks 3’->5’ and 5’->3’ exonuclease activities. The 3’->5’ exonuclease activity of the enzyme is eliminated by D355A and E357A mutations (1). It is a single polypeptide chain with a molecular weight of approximately 68 kDa and displays optimal activity at temperature at 37ºC. The enzyme is provided with 10X Reaction Buffer to perform random-primed DNA labeling or 3’-end labeling of DNA.