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. Author manuscript; available in PMC: 2009 Nov 25.
Published in final edited form as: Biochemistry. 2008 Nov 25;47(47):12434–12447. doi: 10.1021/bi801311d

Figure 4. Product inhibition study of the B. anthracis OSB-CoA synthetase catalyzed reaction.

Figure 4

The kinetic data were displayed as Lineweaver-Burk plots of the reaction rate vs substrate concentrations at different concentrations of the product inhibitor. For each plot, two substrates were kept at constant level while varying the third substrate and the product inhibitor concentrations. (A) AMP is a competitive inhibitor to ATP. OSB and CoA were kept constant at 8 µM and 128 µM, respectively while varying ATP and AMP concentrations (•=0, ○=0.94, ▼=1.88, ◇=3.75, ■=7.5, □=15.0 mM). The inset is a zoom-out of the region where the lines cross at the y-axis. (B) AMP is an uncompetitive inhibitor to CoA. OSB and ATP were kept constant at 8 µM and 16 µM, respectively while varying CoA and AMP concentrations (•=0, ○=1.88, ▼=3.75, ◇=7.5, ■=15.0, □=30.0 mM). (C) Benzoyl-CoA (B-CoA) is a mixed-type inhibitor to CoA. OSB and ATP were kept constant at 8 µM and 16 µM, respectively while varying CoA and benzoyl-CoA concentrations (•=0, ○=0.94, ▼=1.88, ◇=3.75, ■=7.5, □=15.0 mM). (D) AMP is a mixed-type inhibitor to OSB. CoA and ATP were kept constant at 128 µM and 16 µM, respectively while varying OSB and AMP concentrations (•=0, ○=0.94, ▼=1.88, ◇=3.75, ■=7.5, □=15.0, ▲ =30 mM). Each data point in the figures represents the mean of a duplicate test. The upper and lower bars represent the duplicate measurements. The kinetic parameters and patterns are summarized in Table 2.