• DOI:10.1038/35090602
• Corpus ID: 205020153

Catalysis by hen egg-white lysozyme proceeds via a covalent intermediate

@article{Vocadlo2001CatalysisBH,
  title={Catalysis by hen egg-white lysozyme proceeds via a covalent intermediate},
  author={David J. Vocadlo and Gideon J. Davies and Roger A. Laine and Stephen G. Withers},
  journal={Nature},
  year={2001},
  volume={412},
  pages={835-838}
}

• D. Vocadlo, Gideon J. Davies, +1 author S. Withers
• Published 23 August 2001
• Chemistry, Biology
• Nature

Hen egg-white lysozyme (HEWL) was the first enzyme to have its three-dimensional structure determined by X-ray diffraction techniques. A catalytic mechanism, featuring a long-lived oxocarbenium-ion intermediate, was proposed on the basis of model-building studies. The ‘Phillips’ mechanism is widely held as the paradigm for the catalytic mechanism of β-glycosidases that cleave glycosidic linkages with net retention of configuration of the anomeric centre. Studies with other retaining β-glycosidases, however, provide strong evidence pointing to a common mechanism for these enzymes that involves a covalent glycosyl-enzyme intermediate, as previously postulated. Here we show, in three different cases using electrospray ionization mass spectrometry, a catalytically competent covalent glycosyl-enzyme intermediate during the catalytic cycle of HEWL. We also show the three-dimensional structure of this intermediate as determined by X-ray diffraction. We formulate a general catalytic mechanism for all retaining β-glycosidases that includes substrate distortion, formation of a covalent intermediate, and the electrophilic migration of C1 along the reaction coordinate.