Figure 1. Thermal inactivation of restriction enzymes

A time-course of thermal inactivation of restriction enzymes was carried out. Each assay tube had 3 units of the enzyme, 33 ng of BSA, and 0.5% glycerol in a total of 13 ml of 1X buffer, supplied by the manufacturer. SmaI and NdeI were incubated at 37 °C and 45 °C, respectively. The residual activity was determined every 30 min using 200 ng of plasmid DNA. The plasmid digestion was carried out for 90 min at 25 °C and 37 °C for SmaI and NdeI, respectively. The digested mixtures were run on 1% agarose gel and stained with ethidium bromide.