Valence Bond Insights into the H-Abstraction Barrier in Cytochrome P450.

ABSTRACT: The valence bond (VB) framework is widely recognized as a powerful tool for elucidating the electronic origins of activation energy barriers in chemical reactions. We employed ab initio VB calculations to investigate the hydrogen abstraction (H-abstraction) barrier in cytochrome P450 enzymes (P450s), using a simplified model in which an oriented external electric field (OEEF) was applied to efficiently capture the electronic effects of the equatorial porphyrin and proximal thiolate ligands on the iron(IV)-oxo unit in compound I (Cpd I). Methane (CH₄) was used as the model substrate. The VB-calculated barrier height, evaluated with this simplified model, qualitatively reproduced the barrier predicted by density functional theory (DFT) calculations using a more complete active-sit

SUBMITTER: Zhang E 

PROVIDER: S-EPMC12114163 | biostudies-literature | 2025 May

REPOSITORIES: biostudies-literature