Functional effects of active site mutations in NAD+-dependent formate dehydrogenases on transformation of hydrogen carbonate to formate

Bioinspired Framework Catalysts: From Enzyme Immobilization to Biomimetic Catalysis

“…For example, mutation of the active site has been promoted to loosen the restriction of the substrate positioning, elevate the conformational flexibility, and increase the accessibility of the active sites. 467 Changing the positioning of the cofactor to facilitate hydride transfer from NADH to HCO 3 − , resulting in an improved catalytic turnover rate (k cat ) and total catalytic efficiency (k cat /K m ). 468 The active site of the molybdenum-dependent (Mo-FDHs) and tungsten-dependent enzymes (W-FDHs) is Mo or W atom coordinated by two molybdopterin ligands.…”

Catalytic bias in oxidation–reduction catalysis

“…As can be seen from eqn (8), and in the particular case described by eqn (5), the catalytic bias is determined only by the ratio of the forward rate constant of the second step and the backward rate constant of the first step; there is no dependence on the concentration of any species involved in the catalysis (including the catalyst).…”

“…Eqn (8) clearly shows that an enzyme can be a better catalyst in one direction than the other direction depending on the relative magnitude of the rate constants.…”

“…Similarly, some formate dehydrogenases have been shown to have a bias toward formate oxidation. 7,8 For instance, Thiobacillus sp. KNK65MA formate dehydrogenase exhibits a k cat of 1.76 s À1 for formate oxidation relative to 0.318 s À1 for CO 2 reduction, respectively.…”

Directed evolution engineering to improve activity of glucose dehydrogenase by increasing pocket hydrophobicity

“…Aslan et al constructed six variant libraries using a semi-rational design to expand the substrate selectivity of L-lactate dehydrogenase from the thermophilic organism Geobacillus stearothermophilus and achieved variants which could efficiently catalyze α-ketoacids for the preparation of corresponding α-hydroxy acids ( Aslan et al, 2016 ). Berin Yelmazer et al introduced mutations into the active sites of FDH in Candida methylica and Chaetomium thermophilum to explore the mechanism of affecting the binding of HCO 3 − and driving hydrides away from the reaction in the opposite direction by specific mutations ( Pala et al, 2018 ). In previous study, V144L variant of phenylalanine dehydrogenase (PheDH) from Bacillus badius was performed by site-directed mutation, whose substrate phenylalanine specificity was significantly increased by 4-fold comparing to the wild type ( Yousefi et al, 2017 ).…”