Poly(2-oxazoline)s with a 2,2'-Iminodiacetate End Group Inhibit and Stabilize Laccase

Optimizing laccase selection for enhanced outcomes: a comprehensive review

Despite their widespread applications in sectors such as pulp and paper, textile, food and beverage, pharmaceuticals, and biofuel production, laccases encounter challenges related to their activity and stability under varying reaction conditions. This review accumulates data on the complex interplay between laccase characteristics and reaction conditions for maximizing their efficacy in diverse biotechnological processes. Benefits of organic media such as improved substrate selectivity and reaction control, and their risks such as enzyme denaturation and reduced activity are reported. Additionally, the effect of reaction conditions such as pH and temperature on laccase activity and stability are gathered and reported. Sources like Bacillus pumilus, Alcaligenes faecalis, Bacillus clausii, and Bacillus tequilensis SN4 are producing laccases that are both thermo-active and alkali-active. Additionally, changes induced by the presence of various substances within reaction media such as metals, inhibitors, and organic solvents are also reported. Bacillus pumilus and Bacillus licheniformis LS04 produce the most resistant laccases in this case. Finally, the remarkable laccases have been highlighted and the proper laccase source for each industrial application is suggested.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-024-04015-5.

Advanced Strategies in Enzyme Activity Regulation for Biomedical Applications

Enzymes are important macromolecular biocatalysts that accelerate chemical and biochemical reactions in living organisms. Most human diseases are related to alterations in enzyme activity. Moreover, enzymes are potential therapeutic tools for treating different diseases, such as cancer, infections, and cardiovascular and cerebrovascular diseases. Precise remote enzyme activity regulation provides new opportunities to combat diseases. This review summarizes recent advances in the field of enzyme activity regulation, including reversible and irreversible regulation. It also discusses the mechanisms and approaches for on-demand control of these activities. Furthermore, a range of stimulus-responsive inhibitors, polymers, and nanoparticles for regulating enzyme activity and their prospective biomedical applications are summarized. Finally, the current challenges and future perspectives on enzyme activity regulation are discussed.

Full Thermal Switching of Enzymes by Thermoresponsive Poly(2-oxazoline)-Based Enzyme Inhibitors

Controlling the activity of enzymes is an important feature for many processes in medicine, bioanalytics, and biotechnology. So far, it has not been possible to fully switch biocatalysts on and off by thermoresponsive enzyme inhibitors. Herein, we present poly(2-oxazoline)s with iminodiacetic acid end groups (POx-IDA) that are lower critical solution temperature (LCST) polymers and thus thermosensitive. They are capable of reversibly inhibiting the activity of horse radish peroxidase and laccase by more than 99 %. Increasing the temperature makes the POx-IDA precipitate, which leads to 100 % recovery of the enzyme activity. This switching cycle is fully reversible. The LCST of the POx-IDA can be tuned by varying the polymer composition to generate a wide range of switching windows.

Poly(2-oxazoline)s with a 2,2'-Iminodiacetate End Group Inhibit and Stabilize Laccase

Poly(2-oxazoline)s (POxs) with 2,2'-iminodiacetate (IDA) end groups were investigated as inhibitors for laccase. The polymers with the IDA end groups are reversible, competitive inhibitors for this enzyme. The IC50 values were found to be in a range of 1-3 mm. Compared with IDA alone, the activity was increased by a factor of more than 30; thus indicating that attaching a polymer chain to an inhibitor can already improve the activity of the former. The enzyme activity drops to practically zero upon increasing the concentration of the most active telechelic inhibitor, IDA-PEtOx30 -IDA (PEtOx: poly(2-ethyl-2-oxazoline)), from 5 to 8 mm. This unusual behavior was investigated by means of dynamic light scattering, which showed specific aggregation above 5 mm. Furthermore, the laccase could be stabilized in the presence of POx-IDA, upon addition at a concentration of 20 mm and higher. Whereas laccase becomes completely inactive at room temperature after one week, the stabilized laccase is fully active for at least a month in aqueous solution.

Inhibition in multicopper oxidases: a critical review

This review critiques the literature on inhibition of O₂-reduction catalysis in multicopper oxidases like laccase and bilirubin oxidase and provide recommendations for best practice when carrying out experiments and interpreting published data.