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. Author manuscript; available in PMC: 2017 Dec 22.
Published in final edited form as: Biochemistry. 2017 Aug 29;56(36):4786–4798. doi: 10.1021/acs.biochem.7b00619

Figure 4. Determination of metformin inhibition constant for ecDHFR.

Figure 4

A) Lineweaver-Burk plot for the inhibition of ecDHFR with Metformin (MFM). All of the lines intersect at the same point on the y-axis indicating competitive inhibition of MFM with DHF. The inset shows the slopes plotted versus [MFM]. Error bars from fits of the slopes are shown. A fit of the data (R2 = 0.970) yields a Ki of 24 ± 7 mM for MFM. A non-linear fit of all of the data yielded a Ki = 17.9 ± 3.5 mM. B) Lineweaver-Burk plot of PFM inhibition of ecDHFR. The pattern of intersecting lines indicates competitive inhibition. The slopes are plotted versus [PFM] in the inset plot. Error bars for the slopes are shown. A fit of the data (R2 = 0.992) yields a Ki of 0.17 ± 0.02 mM.