Fungal Laccases with High and Medium Redox Potential: Is the T1 Center Potential a Key Characteristic of Catalytic Efficiency in Heterogeneous and Homogeneous Reactions?

TL;DR

This paper compares fungal laccases with different redox potentials to see how their T1 center potential affects their performance in various reactions.

Contribution

The study reveals a correlation between T1 center potential and electrocatalytic efficiency but not with homogeneous reactions.

Findings

High-redox-potential laccases (ThL, CcL) showed better electrocatalytic performance.

No correlation was found between T1 center potential and homogeneous reaction efficiency.

Structural data was used to interpret the electrocatalytic results.

Abstract

Catalytic and bioelectrocatalytic properties of four white rot fungal laccases (Trametes hirsuta, ThL; Coriolopsis caperata, CcL; Steccherinum murashkinskyi, SmL; and Antrodiella faginea, AfL) from different orthologous groups were comparatively studied in homogeneous reactions of electron donor substrate oxidation and in a heterogeneous reaction of dioxygen electroreduction. The ThL and CcL laccases belong to high-redox-potential enzymes (E0T1 = 780 mV), while the AfL and SmL laccases are medium-redox-potential enzymes (E0T1 = 620 and 650 mV). We evaluated the efficiency of laccases in mediatorless bioelectrocatalytic dioxygen reduction by the steady-state potential (Ess), onset potential (Eonset), half-wave potential (E1/2), and the slope of the linear segment of the polarization curve. A good correlation was observed between the T1 center potential of the laccases and their electrocatalytic characteristics; however, no correlation with the homogeneous reactions of electron donor substrates’ oxidation was detected. The results obtained are discussed in the light of the known data on the three-dimensional structures of the laccases studied.

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