title: The hard-soft acid-base principle in enzymatic catalysis: dual reactivity of phosphoenolpyruvate.
abstract: In this paper, the chemical reactivity of C3 of phosphoenolpyruvate (PEP) has been analyzed in terms of density functional theory quantified through quantum chemistry calculations. PEP is involved in a number of important enzymatic reactions, in which its C3 atom behaves like a base. In three different enzymatic reactions analyzed here, C3 sometimes behaves like a soft base and sometimes behaves like a hard base in terms of the hard-soft acid-base principle. This dual nature of C3 of PEP was found to be related to the conformational change of the molecule. This leads to a testable hypothesis: that PEP adopts particular conformations in the enzyme-substrate complexes of different PEP-using enzymes, and that the enzymes control the reactivity through controlling the dihedral angle between the carboxylate and the C==C double bond of PEP.
authors.affiliation: Department of Biochemistry and Biophysics, Washington State University, Pullman, 99164-4660, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Li
authors.forename: J N
authors.initials: JN
authors.lastname: Evans
mesh_terms: D010723:3-Deoxy-7-Phosphoheptulonate Synthase / Q000737:chemistry / Q000378:metabolism; D051229:3-Phosphoshikimate 1-Carboxyvinyltransferase; D000446:Aldehyde-Lyases / Q000737:chemistry / Q000378:metabolism; D019883:Alkyl and Aryl Transferases; D002384:Catalysis; D004798:Enzymes / Q000737:chemistry* / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008956:Models, Chemical; D008968:Molecular Conformation; D010728:Phosphoenolpyruvate / Q000737:chemistry* / Q000378:metabolism*; D011789:Quantum Theory; D013816:Thermodynamics; D014166:Transferases / Q000737:chemistry / Q000378:metabolism
chemical_list: D004798:Enzymes; D010728:Phosphoenolpyruvate; D014166:Transferases; D019883:Alkyl and Aryl Transferases; D051229:3-Phosphoshikimate 1-Carboxyvinyltransferase; D010723:3-Deoxy-7-Phosphoheptulonate Synthase; C020011:2-dehydro-3-deoxyphosphooctonate aldolase; D000446:Aldehyde-Lyases