Researchers found that adding the peptide‑copper complex GHK‑Cu to the growth medium of the fungus Trametes versicolor makes it produce a lot more of the enzyme laccase than using regular copper salts. The new method boosts enzyme levels by about 13‑fold and is safer because GHK‑Cu damages the fungal cells less.

A highly efficient strategy using Copper-Glycyl-L-Histidyl-L-Lysine (GHK-Cu) as a novel inducer was developed to enhance laccase production by <i>Trametes versicolor</i>. After medium optimization, laccase activity increased by 12.77-fold compared to that without GHK-Cu. The laccase production of 1113.8&#xa0;U L^-1 was obtained by scaling-up culture in 5-L stirring tank. The laccase production induced by CuSO₄ was poorer than that of GHK-Cu at the same mole concentration. GHK-Cu could increase the permeability of cell membrane with less damage, and it facilitated the adsorption, accumulation, and utilization of copper by fungal cells, which was beneficial for laccase synthesis. GHK-Cu induced better expression of laccase related genes than that of CuSO₄, resulting in higher laccase production. This study provided a useful method for induced production of laccase by applying GHK chelated metal ion as a non-toxic inducer, which reduced the safety risk of laccase broth and provided the potential application of crude laccase in food industry. In addition, GHK can be used as the carrier of different metal ions to enhance the production of other metalloenzymes.