Catalysis by peptide-based enzyme models

The preparation of artificial proteins capable of catalyzing (non-)biological reactions with an efficiency and specificity comparable to enzymes is one of the most intellectually challenging tasks in the field of peptide chemistry. Therefore, the development of small peptide-based catalysts that mimic enzymes continues to be a very popular theme in research. Chemists have adopted different strategies to reach this ambitious target.Generally, one can differentiate between \u93natural\u94 systems and (almost) entirely synthetic systems, both of which have yielded interesting results. Natural systems are based on the naturally available set of amino acids, whereas in synthetic systems this set has been expanded with a wide variety of man-made building blocks. The use of artificial building blocks allows for an increase in variety of the catalysts and catalytic reactions that can be targeted, and allows also for a (partial) compensation of the loss of protein framework in stabilizing secondary structures