Liquid. In 50 mM potassium phosphate buffer, 0.25 mM dithiothreitol, 50% glycerol, pH 7.0. AVOID FREEZE/THAW CYCLES. The large fragment of DNA polymerase I. The Klenow fragment exhibits 5′ to 3′ DNA polymerase and 3′ to 5′ exonuclease activity, but lacks the 5′ to 3′ exonuclease activity of intact DNA polymerase I. One unit is the amount of enzyme required to incorporate 10 nmol of total nucleotide into acid-insoluble form in 30 min at 37°C.

Ref.: Telford, J.L. et al. 1979. Proc. Natl. Acad. Sci. USA 76, 2590. Wickens, M.P. 1978. J. Biol. Chem. 253, 2483. Sanger, F., et al. 1977. Proc. Natl. Acad. Sci. USA 74, 5463. Jaccobsen, H., et al. 1974. Eur. J. Biochem. 45, 623.