Deuterium Kinetic Isotope Effects Resolve Low-Temperature Substrate Radical Reaction Pathways and Steps in B₁₂-Dependent Ethanolamine Ammonia-Lyase.

ABSTRACT: The first-order reaction kinetics of the cryotrapped 1,1,2,2-²H₄-aminoethanol substrate radical intermediate state in the adenosylcobalamin (B₁₂)-dependent ethanolamine ammonia-lyase (EAL) from Salmonella enterica serovar Typhimurium are measured over the range of 203-225 K by using time-resolved, full-spectrum electron paramagnetic resonance spectroscopy. The studies target the fundamental understanding of the mechanism of EAL, the signature enzyme in ethanolamine utilization metabolism associated with microbiome homeostasis and disease conditions in the human gut. Incorporation of ²H into the hydrogen transfer that follows the substrate radical rearrangement step in the substrate radical decay reaction sequence leads to an observed

SUBMITTER: Kohne M 

PROVIDER: S-EPMC7387329 | biostudies-literature | 2019 Sep

REPOSITORIES: biostudies-literature