Multicopper oxidases (MCOs) are lignin degrading enzymes with four copper sites involved in their catalysis. The consensus mechanism suggests that substrate oxidation occurs near a type 1 Cu center (CuT1), followed by long-range electron transfer to a trinuclear Cu center (TNC) where O2 is reduced to H2O. Although laccases are capable of aerobic oxidation of lignin as their primary function, the potential of CuT1 (E°(Cu2+/+) ≈ 0.5 V vs. NHE, pH 5.5) is as much as 0.5 V lower than that expected for one-electron oxidation of polyphenolic substrates. Investigations on redox-active residues critical for enzyme catalysis as well as reactive intermediates are crucial for elucidating this potential discrepancy and the mechanistic details of substrate oxidation. Our study focused on the MCO from a thermophilic bacterium, Thermus thermophilus HB27 (T. thermophilus Laccase) in particular (Figure 1), which is stable and active even above 90°C. Thus, thermodynamic parameters associated with the enzyme’s thermostability and improved activity at elevated temperatures are of special importance. Approaches to enhancing our understanding of how the enzyme has evolved to utilize O2 to degrade lignin from recalcitrant lignocellulosic substrates will be useful for developing environmentally friendly biocatalysts.

Kinetic and thermodynamic studies on T. thermophilus laccase catalysis

Macromolecular Chemistry: The Second Century

[Author Benefits](https://scimeetings.acs.org/?utm_source=pubs_content_marketing&utm_medium=website&utm_campaign=0320_MCF_NPI_Launch_Spring_Homepage&ref=pubs_content_marketing)

[How to use SciMeetings](https://storage.googleapis.com/dl.morressier.com/acs/SciMeetings-ACSSpring2020-HowToGuide_M3020-Final.pdf)

[Frequently Asked Questions](https://storage.googleapis.com/dl.morressier.com/acs/SciMtng_ACSNMSp2020_FAQ_M3120_Final.pdf)

ACS Spring 2020 National Meeting & Expo

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.