A new perspective on thiamine catalysis.

Our knowledge of thiamine-catalyzed ligase and lyase reactions has entered a new dimension. Significant achievements have been made in the field of enzymatic catalysis with the detection of hitherto unknown reaction types - extending the synthetic potential of known thiamine diphosphate (ThDP)-dependent enzymes - and the identification and characterization of new enzymes. As we learn more about ThDP-dependent enzymes, we find an ever-expanding range of reactions that they are able to catalyze and see increased amino acid sequence heterogeneity. By contrast, the three-dimensional structures of these enzymes, so far, seem to be highly similar. Non-enzymatic thiazolium and triazolium catalysts have also been developed, enhancing the scope of acyl anion chemistry.