The structure and synthetic capabilities of a catalytic peptide formed by substrate-directed mechanism--implications to prebiotic catalysis.

Previously, we have shown that a small substrate may serve as a template in the formation of a specific catalytic peptide, a phenomenon which might have had a major role in prebiotic synthesis of peptide catalysts. This was demonstrated experimentally by the formation of a catalytic metallo-dipeptide, Cys2-Fe2+, around o-nitrophenyl beta-D-galactopyranoside (ONPG), by dicyandiamide (DCDA)-assisted condensation under aqueous conditions. This dipeptide was capable of hydrolyzing ONPG at a specific activity lower only 1000 fold than that of beta galactosidase.