Determining the esterase activity of peptides and peptide assemblies.

Catalytic peptides are gaining attention as alternatives to enzymes, especially in industrial applications. Recent advances in peptide design have improved their catalytic efficiency with approaches such as self-assembly and metal ion complexation. However, the fundamental principles governing peptide catalysis at the sequence level are still being explored. Ester hydrolysis, a well-studied reaction, serves as a widely employed method to evaluate the catalytic potential of peptides. The standard colorimetric reaction involving para-nitrophenyl acetate hydrolysis acts as a benchmark assay, providing a straightforward and efficient screening method for rapidly identifying potential catalysts. However, maintaining standardized conditions is crucial for reproducible results, given that factors such as pH, temperature, and substrate concentration can introduce unwanted variability. This necessity becomes particularly pronounced when working with peptides, which often exhibit slower reaction rates compared to enzymes, making even minor variations significantly influential on the final outcome. In this context, we present a refined protocol for assessing the catalytic activity of peptides and peptide assemblies, addressing critical considerations for reproducibility and accuracy.