A functionally diverse enzyme superfamily that abstracts the α protons of carboxylic acids Academic Article uri icon


MeSH Major

  • Hydro-Lyases
  • Intramolecular Lyases
  • Isomerases
  • Protons
  • Pseudomonas putida
  • Racemases and Epimerases


  • Mandelate racemase and muconate lactonizing enzyme are structurally homologous but catalyze different reactions, each initiated by proton abstraction from carbon. The structural similarity to mandelate racemase of a previously unidentified gene product was used to deduce its function as a galactonate dehydratase. In this enzyme superfamily that has evolved to catalyze proton abstraction from carbon, three variations of homologous active site architectures are now represented: lysine and histidine bases in the active site of mandelate racemase, only a lysine base in the active site of muconate lactonizing enzyme, and only a histidine base in the active site of galactonate dehydratase. This discovery supports the hypothesis that new enzymatic activities evolve by recruitment of a protein catalyzing the same type of chemical reaction.

publication date

  • February 24, 1995



  • Academic Article



  • eng

PubMed ID

  • 7855594

Additional Document Info

start page

  • 1159

end page

  • 61


  • 267


  • 5201