I wonder how stable Klenow Exo- is in -20 degrees and if the stability can be improved at -80 degrees. The source of the enzyme is from ThermoFischer Scientific and stored in 25 mMTris-HCl (pH 7.5), 0.1 mM EDTA, 1 mM DTT and 50% (v/v) glycerol.

Another question is that I wonder if the Mg2+ concentration can be decreased in the buffer used for enzyme activity (final concentration 5 mM MgCl2) without losing any activity.