Figure 3. Inhibition of polymerase activity at high concentrations of enzyme. Although a single gel, the white horizontal midline divides undiluted aliquots (Panel A) from diluted ones (Panel B). Samples were applied at the top of each panel and electrophoresed simultaneously. Panel A shows PCR products 2.5 kb in size using 1uL of undiluted FPLC fractions 1 through 15. Panel B shows corresponding PCR products from 1uL of 1:10 diluted FPLC fractions. Lane M is DNA size marker (l/HindIII) Note inhibition of activity in concentrated samples in lanes 4 through 8 of Panel A. This inhibition is not observed when smaller products are amplified as with the 0.6 kb product in Figure 2. The bright patches of lanes 5 through 8 at the top of panel B are due to migration of primers from samples in panel A.