Laccases or benzenediol oxygen oxidoreductases (EC 1.10.3.2) are polyphenol multicopper oxidases that are known for their structural and functional diversity in various life forms. In the present study, the molecular and physico-chemical properties (redox-potential and secondary structures) of fungal laccase isozymes (FLIs) isolated from a medicinal mushroom Ganoderma lucidum were analyzed and compared with those of the recombinant bacterial laccases (rLac) obtained from different Yersinia enterocolitica strains. It was revealed that the FLIs contained His-Cys-His as the most conserved residue in its domain I Cu site, while the fourth and fifth residues were variable (Ile, Leu, or Phe). Evidently, the cyclic voltammetric measurements of Glac L2 at Type 1 Cu site revealed greater E° for ABTS/ABTS⁺ (0.312 V) and ABTS⁺/ABTS²⁺ (0.773 V) compared to the E° of rLac. Furthermore, circular dichroism-based conformational analysis revealed structural stability of the FLIs at acidic pH (3.0) and low temperature (<30 °C), while the isozymes were destabilized at neutral pH (7.0) and high-temperature conditions (>70 °C). The zymographic studies further confirmed the functional inactivation of FLIs at high temperatures (≥70 °C), predominantly due to domain unfolding. These findings provide novel insight into the evolution of the catalytic efficiency and redox properties of the FLIs, contributing to the existing knowledge regarding stress responses, metabolite production, and the biotechnological utilization of metabolites.

漆酶或苯二酚氧氧化还原酶（EC 1.10.3.2）是多酚多铜氧化酶，以其在各种生命形式中的结构和功能多样性而著称。在本研究中，分析了分离自药用蘑菇灵芝的真菌漆酶同工酶（FLIs）的分子和理化性质（氧化还原电位和二级结构），并将其与从中获得的重组细菌漆酶（rLac）进行了比较。不同的小肠结肠炎耶尔森氏菌株。结果表明，FLI在其结构域I Cu位点中包含His-Cys-His作为最保守的残基，而第四和第五个残基是可变的（Ile，Leu或Phe）。显然，在1型铜位点处Glac L2的循环伏安测量显示ABTS / ABTS ⁺（0.312 V）和ABTS ⁺ / ABTS ²⁺具有更大的E°（0.773 V）相较于rLac的E°。此外，基于圆二色性的构象分析揭示了FLI在酸性pH（3.0）和低温（<30°C）下的结构稳定性，而同工酶在中性pH（7.0）和高温条件（> 70°C）下不稳定。 C）。酶谱研究进一步证实了高温下（≥70°C）FLI的功能失活，主要是由于结构域展开。这些发现为FLI的催化效率和氧化还原特性的演变提供了新颖的见解，为有关应激反应，代谢产物产生和代谢物生物技术利用的现有知识做出了贡献。