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. ...