Transition state structure, in solution

Figure 2.4 Thermodynamic cycle for substrate transition to its transition state structure in solution and after binding to an enzyme.

Cross-interaction constants and transition-state structure in solution, 27, 57 Crown-ether complexes, stability and reactivity of, 17,279 Crystallographic approaches to transition state structures, 29,87 Cyclodextrins and other catalysts, the stabilization of transition states by, 29,1... 

Effective charge and transition-state structure in solution, 27, 1 Effective molarities of intramolecular reactions, 17,183 Electrical conduction in organic solids, 16,159 Electrochemical methods, study of reactive intermediates by, 19, 131 Electrochemical recognition of charged and neutral guest species by redox-active receptor molecules, 31, 1... 

Tetrahedral intermediates, derived from carboxylic acids, spectroscopic detection and the investigation of their properties, 21, 37 Topochemical phenomena in solid-state chemistry, 15, 63 Transition state structure, crystallographic approaches to, 29, 87 Transition state structure, in solution, effective charge and, 27, 1 Transition state structure, secondary deuterium isotope effects and, 31, 143 Transition states, structure in solution, cross-interaction constants and, 27, 57 Transition states, the stabilization of by cyclodextrins and other catalysts, 29, 1 Transition states, theory revisited, 28, 139... 

Transition stale structure, secondary deuterium isotope effects and, 31, 143 Transition states, structure in solution, cross-interaction constants and, 27, 57 Transition states, the stabilization of by cyclodextrins and other catalysts, 29, 1 Transition states, theory revisited, 28, 139... 

In both solvents, the variational transition state (associated with the free energy maximum) corresponds, within the numerical errors, to the dividing surface located at rc = 0. It has to be underlined that this fact is not a previous hypothesis (which would rather correspond to the Conventional Transition State Theory), but it arises, in this particular case, from the Umbrella Sampling calculations. However, there is no information about which is the location of the actual transition state structure in solution. Anyway, the definition of this saddle point has no relevance at all, because the Monte Carlo simulation provides directly the free energy barrier, the determination of the transition state structure requiring additional work and being unnecessary and unuseful. 

Effective Charge and Transition-State Structure in Solution... 

In one approach, the free energies of binding, out of water into the enzyme active site, of the reactant(s) and transition structure are computed, in order to see if rate acceleration can be explained by selective binding of the transition structure. However, there are several caveats associated with such an approach. First, it must be decided whether to use the same reactant and transition state structures in solution and in the enzyme. If the same structures are used, then the potential for catalysis specifically by selective transition state binding can be quantified. Of course, the actual enzyme-bound structures may be different than those in aqueous solution, and... 

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