Enzyme catalysis and hydrogen bonding

Chemical reactivity and hydrogen bonding 320 Proton-transfer behaviour 321 Intramolecular hydrogen-bond catalysis 344 Enzyme catalysis and hydrogen bonding 354 Chymotrypsin 354 Thermolysin 355 Carboxypeptidase 355 Tyrosyl tRNA synthetase 356 Summary 366 Acknowledgements 367 References 367... 

Sim6n, L. Goodman, J. M. Enzyme catalysis by hydrogen bonds The balance between transition state binding and substrate binding in oxyanion holes, J. Org. Chem. 2009, 75,1831-1840. 

Since enzyme catalysis and regulation are dynamic processes, the dynamics of hydrogen bonding is also an important consideration. In relatively weakly hydrogen bonding solvents, such as the first four entries in Table I, the association rate is essentially diffusion controlled, whereas the association rate constants for the last two entries are considerably less than expected for a diffusion-controlled process. This can be understood... 

By using imidazole catalysis, it is possible to get a better understanding of the active forms that water takes in enzymatic processes Thus, at low concentrations m the presence of an enzyme, the water may not be fully hydrogen bonded and therefore more reactive [61] The rate of hydrolysis of p-nitrotrifluoroacetanilide in acetonitrile shows a strong dependence on water concentration at low levels in the presence of imidazole The imidazolium complex is the approximate transition state (equation 60)... 

Gerlt, J. A., Kreevoy, M. M., Cleland, W. W., and Frey, P. A., 1997. Understanding enzymic catalysis The importance of short, strong hydrogen bonds. Chemistry and Biology 4 259-267. 

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