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Updated: Aug 8, 2026

Unraveling Entropic Rate Acceleration Induced by Solvent Dynamics in Membrane Enzymes
Published on: January 16, 2016
Strain energy release and intrinsic barriers in internal nucleophilic reactions
Joel L Wolk1, Esther Rozental, Harold Basch
1Department of Chemistry, Bar-Ilan University, Ramat-Gan, Israel 52900.
Abstract:
This paper reports computational data for the energetics of internal attacks, both in ring-opening reactions (eq 3) where strain energy is released and in model, strain-free systems (eq 4). A comparison is drawn with the corresponding bimolecular processes. The exothermicity of three-membered ring-opening reactions is significantly larger than that of the four-membered ring systems. However, using the Marcus equation, it is shown that the higher reactivity of the three-membered rings is intrinsic to the system and does not stem only from a higher thermodynamic driving force. The intrinsic barriers for the strain-free reactions are shown to be dominated by the position of the nucleophilic and nucleofugic atoms in the periodic table, as in the bimolecular SN2 reactions, although a pi rather than a sigma bond is formed in these reactions.
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