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Updated: May 8, 2026

Unraveling Entropic Rate Acceleration Induced by Solvent Dynamics in Membrane Enzymes
Published on: January 16, 2016
Kinetic evidence of an apparent negative activation enthalpy in an organocatalytic process
Xiao Han1, Richmond Lee, Tao Chen
1KAUST Catalysis Center and Division of Physical Science and Engineering, King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia.
Abstract:
A combined kinetic and computational study on our tryptophan-based bifunctional thiourea catalyzed asymmetric Mannich reactions reveals an apparent negative activation enthalpy. The formation of the pre-transition state complex has been unambiguously confirmed and these observations provide an experimental support for the formation of multiple hydrogen bonding network between the substrates and the catalyst. Such interactions allow the creation of a binding cavity, a key factor to install high enantioselectivity.
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