Abstract
A theoretical approach designed for chemical reactions in the condensed phase is used to determine the energy along the reaction path of the enzyme triosephosphate isomerase. The calculations address the role of the enzyme in lowering the barrier to reaction and provide a decomposition into specific residue contributions. The results suggest that, although Lys-12 is most important, many other residues within 16 Á of the substrate contribute and that histidine-95 as the imidazole/imidazolate pair could act as an acid/base catalyst.