The Organization of Active Site Side Chains of Glycerol-3-phosphate Dehydrogenase Promotes Efficient Enzyme Catalysis and Rescue of Variant Enzymes.

ABSTRACT: A comparison of the values of k_cat/K_m for reduction of dihydroxyacetone phosphate (DHAP) by NADH catalyzed by wild type and K120A/R269A variant glycerol-3-phosphate dehydrogenase from human liver (hlGPDH) shows that the transition state for enzyme-catalyzed hydride transfer is stabilized by 12.0 kcal/mol by interactions with the cationic K120 and R269 side chains. The transition state for the K120A/R269A variant-catalyzed reduction of DHAP is stabilized by 1.0 and 3.8 kcal/mol for reactions in the presence of 1.0 M EtNH₃⁺ and guanidinium cation (Gua⁺), respectively, and by 7.5 kcal/mol for reactions in the presence of a mixture of each cation at 1.0 M, so that the transition state stabilization by the ternary E·EtN

SUBMITTER: Cristobal JR 

PROVIDER: S-EPMC7207223 | biostudies-literature | 2020 Apr

REPOSITORIES: biostudies-literature