Peptide fragment screening towards a new inhibitor of neutrophil elastase

Abstract: The main purpose of this master thesis was to test a novel approach of finding leads for new pharmaceuticals, by using Solid Phase Peptide Synthesis (SPPS) in combination with Weak Affinity Chromatography (WAC). Put in a more concrete way, the objective was to find a lead for a better human neutrophil elastase inhibitor. The plan was to take advantage of the fact that the tripeptide Valine-Proline-Valine is a known binder to elastase, and synthesis peptide libraries of tripeptides and test the binding affinity using WAC. Unfortunately, the in-house method of binding the protein onto the WAC-column was not compatible with human elastase, so porcine elastase was used instead. A hit for a new lead was possibly discovered, but the data are inconclusive as the reference binder did not show any binding in the assay, raising the suspicious of denatured protein. To validate the method, the same setup, but with a different protein, porcine trypsin and reference binder Threonine-Arginine-Glutamine was also evaluated. According to the results tripeptides with Ac-X-Glutamine-Valine-NH2 showed potential to have inhibitory effect, but the design of the additional libraries focusing on this sequence showed negative results. Any future experiments should test amino acids with saturated carbon side chains in position X, as all amino acids in this position for the first trypsin WAC run were of that type.