Construction and stabilization of a peptide-based peroxidase mimic for the colorimetric detection of uric acid and sarcosine

Abstract Peptide assembly provides a new approach for the construction of enzyme-like catalysts. However, low stability is still a big challenge for the peptide-based enzyme mimics because the non-covalently driven structures are often destroyed when exposed to environmental changes. Inspired by the catalytic centre of natural horseradish peroxidase (HRP) and the biological function of dityrosine in structural proteins, in this study, we presented the construction of a stable peptide-based HRP mimic (CCA-YH) through introducing covalent bonds. CCA-YH was obtained through the co-assembly of YYHYY and hemin, followed by a ruthenium-mediated photo-crosslinking reaction. Catalytic activity assay demonstrated that CCA-YH displayed enhanced catalytic ability than the non-covalent co-assemblies (CA-YH). Remarkably, CCA-YH exhibited superior long-term stability than CA-YH and natural HRP under different pH, temperature, ion strength and organic medium environments, as well as a favorable reusability. Finally, CCA-YH was applied to the colorimetric detection of uric acid and sarcosine in human urine, which displayed satisfactory sensitivity, specificity and reproducibility. This is the first report the construction of stable peptide-based enzyme mimic based on covalent co-assembly strategy.