Dynamic Protonation States Underlie Carbene Formation in ThDP-Dependent Enzymes: A Theoretical Study.

ABSTRACT: The activation mechanism of thiamine diphosphate (ThDP) in enzymes has long been the subject of intense research and controversial discussion. Particularly contentious is the formation of a carbene intermediate, the first one observed in an enzyme. For the formation of the carbene to take place, both intramolecular and intermolecular proton transfer pathways have been proposed. However, the physiologically relevant pH of ThDP-dependent enzymes around neutrality does not seem to be suitable for the formation of such reactive chemical species. Herein, we investigate the general mechanism of activation of the ThDP cofactor in human transketolase (TKT), by means of electronic structure methods. We show that in the case of the human TKT, the carbene species is accessible through a pK

SUBMITTER: Uranga J 

PROVIDER: S-EPMC10688766 | biostudies-literature | 2023 Sep

REPOSITORIES: biostudies-literature