The deuterium isotope effect on the NMR signal of the low-barrier hydrogen bond in a transition-state analog complex of chymotrypsin.

@article{Cassidy2000TheDI,
  title={The deuterium isotope effect on the NMR signal of the low-barrier hydrogen bond in a transition-state analog complex of chymotrypsin.},
  author={Chris Cassidy and J Lin and Perry Allen Frey},
  journal={Biochemical and biophysical research communications},
  year={2000},
  volume={273 2},
  pages={789-92}
}
The participation of a low-barrier hydrogen bond (LBHB) in the mechanism of action of chymotrypsin introduces a new role for Asp 102 and His 57 in catalysis [C. S. Cassidy, J. Lin, and P. A. Frey (1997) Biochemistry 36, 4576-4584]. It is postulated that the LBHB increases the basicity of His 57-N(epsilon2) in the transition state, thereby facilitating the abstraction of a proton from Ser 195, and stabilizes the tetrahedral intermediate in the acylation step. Evidence for this mechanism includes… CONTINUE READING