Kinetic mechanism of fuculose-1-phosphate aldolase from the hyperthermophilic Archaeon Methanococcus jannaschii

Fuculose-1-phosphate aldolase (FucA) is a useful biocatalyst with potential applications in chiral synthesis. In this study, the overall kinetic mechanism of FucA from the archaeon Methanococcus jannaschii was studied. The K-m values of dihydroxyacetone phosphate (DHAP) and DL-glyceraldehyde were 0.09 and 0.74 mM, respectively. Dead-end inhibition by trimethyl phosphonoacetate and DL-threose were competitive and uncompetitive with respect to DHAP and DL-glyceraldehyde. Inhibition patterns obtained using reaction products were noncompetitive vs. DHAP and competitive vs. DL-glyceraldehyde. The equilibrium constant was 8.309 x 10(-3) M as assessed by varying the [DHAP]/[product] ratio at a fixed DL-glyceraldehyde concentration and by measuring the change in DHAP concentration after equilibrium was reached. This constant is consistent with the K-eq value obtained from C-13 NMR (15.625 x 10(-3) M). The resultant inhibition kinetics may suggest the insights of kinetic mechanism of the FucA catalyzed reaction. (C) 2012 Elsevier Inc. All rights reserved.