The Laccase-like Property of GHK-Cu and Its Applications in Colorimetric Sensing of Phenolic Compounds.
This study investigated the catalytic properties of GHK-Cu (a copper-bound tripeptide composed of glycine, histidine, and lysine) as a mimic of the enzyme laccase, which is naturally used in the detection and degradation of phenolic compounds. Researchers characterized GHK-Cu's enzyme-like kinetics, finding a maximum reaction velocity (Vmax) of 1.735 × 10⁻⁴ mM·s⁻¹ and a Michaelis constant (Km) of 0.061 mM, suggesting strong substrate affinity and catalytic efficiency compared to natural laccase. Building on this, the team developed colorimetric assays to detect two phenolic compounds—epinephrine (EP) and 2-aminophenol (2-AP)—across defined concentration ranges in ultrapure water and seawater. Additionally, a portable cotton-based sensor paired with a smartphone platform was constructed to enable field-ready detection of 2-AP in seawater. The study is conducted entirely in vitro and focuses on analytical chemistry applications rather than biological or therapeutic effects of GHK-Cu. Key limitations include the absence of any cell-based, animal, or human testing; findings are restricted to a controlled laboratory sensing context. The work proposes GHK-Cu's copper-coordination structure as a template for designing novel synthetic laccase mimetics.
Why this grade: The entire study was conducted in laboratory solution and sensor-strip formats with no cell, animal, or human components, limiting evidence to in vitro analytical chemistry only.
Laccase plays an important role in the detection and degradation of phenolic compounds, but it is limited by its cost and stability. In this study, the laccase-like property of copper peptide (GHK-Cu) has been revealed. In terms of enzymatic reaction kinetics, GHK-Cu has a V max of 1.735 × 10 -4 mM·s -1 and a K m of 0.061 mM, demonstrating good substrate affinity and excellent catalytic efficiency. Then, a colorimetry was developed for rapid detection of epinephrine (EP) and 2-aminophenol (2-AP). The linear response range of EP is 20-240 μM, with a limit of detection (LOD) of 9.5 μM. The linear response ranges of 2-AP are 14-100 μM (in ultrapure water) and 2-120 μM (in seawater), with LODs of 2.56 μM and 1.65 μM. In addition, combined with a smartphone platform, a cotton-based sensor has been developed for the detection of 2-AP in seawater. The linear response ranges are 0-0.2 mM and 0.2-1 mM, with LOD of 0.033 mM. The structure of GHK-Cu provides a reference for the development of novel laccase mimetic enzymes. The constructed colorimetry offers an option for the rapid detection of phenolic compounds, and the developed cotton-based sensor enabled rapid and portable detection of 2-AP.
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