Lineweaver-Burk plots for GPP and FPP syntheses catalyzed by FPP synthase (conditions described in Materials and Methods). (A) Lineweaver-Burk plot, secondary replot (box), and proposed kinetic mechanism for DMAPP as the allylic substrate. (B) GPP as the allylic substrate with FPP synthase. Symbols: •, 10 μM IPP; ▿, 20 μM IPP; ▪, 30 μM IPP; and ⋄, 50 μM IPP.