FIGURE 2.
The number of CpGs in a promoter increases the rate of product formation. The turnover rate was calculated for DNMT3A on substrates with a varying CpG sites. A, kcat values were compared with the number of CpG sites in the DNA substrate. Each point is the kcat value for the human promoters and synthesized substrate with one CpG site. The inset includes poly(dI-dC). The regression line shows R2 = 0.85, with R2 = 0.98 for the inset. B, comparing the length of DNA with kcat values shows little correlation (R2 = 0.45). C–E, substrate inhibition plots for the PCR-amplified human promoters, which are representative plots for obtaining Vmax data. Vmax values were divided by the amount of active enzyme in the reaction to obtain kcat values.