title: Artificial aldolases from peptide dendrimer combinatorial libraries.
abstract: Peptide dendrimers were investigated as synthetic models for aldolase enzymes. Combinatorial libraries were prepared with aldolase active residues such as lysine and proline placed at the dendrimer core or near the surface. On-bead selection for aldolase activity was carried out using the dye-labelled 1,3-diketone 1a, suitable for covalent trapping of enamine-reactive side-chains, and the fluorogenic enolization probe 6. Aldolase dendrimers catalyzed the aldol reaction of acetone, dihydroxyacetone and cyclohexanone with nitrobenzaldehyde. Much like enzymes, the dendrimers exhibited strong aldolase activity in aqueous medium, but were also active in organic solvent. Dendrimer-catalyzed aldol reactions reached complete conversion in 3 h at 25 degrees C with 1 mol% catalyst and gave aldol products with up to 65% ee. A positive dendritic effect in catalysis was observed with both lysine and proline based aldolase dendrimer catalysts.
authors.affiliation: Department of Chemistry and Biochemistry, University of Berne, Freiestrasse 3, CH-3012, Berne, Switzerland.
authors.forename: Jacob
authors.initials: J
authors.lastname: Kofoed
authors.forename: Tamis
authors.initials: T
authors.lastname: Darbre
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Reymond
mesh_terms: D000596:Amino Acids / Q000737:chemistry; D020650:Combinatorial Chemistry Techniques; D005634:Fructose-Bisphosphate Aldolase / Q000138:chemical synthesis* / Q000737:chemistry*; D007202:Indicators and Reagents; D009682:Magnetic Resonance Spectroscopy; D019151:Peptide Library; D010455:Peptides / Q000138:chemical synthesis* / Q000737:chemistry; D011392:Proline; D013912:Threonine
chemical_list: D000596:Amino Acids; D007202:Indicators and Reagents; D019151:Peptide Library; D010455:Peptides; D013912:Threonine; D011392:Proline; D005634:Fructose-Bisphosphate Aldolase