The effect of lignin model compound structure on the rate of oxidation catalyzed by two different fungal laccases

摘要: Abstract Laccases (EC 1.10.3.2) are multicopper oxidases able to oxidize various substrates, such as phenolic subunits of lignin. The substrate range can be widened non-phenolic units by the use mediators. Since discovery laccase-mediator system, direct reactions lignin and laccase without mediated electron-transfer have gained much less attention. objective this study was investigate a for fungal laccases using model compounds. These compounds contained guaiacylic syringylic moieties also origin at higher oxidation level. Some these commercially available, but most them were synthesized. reaction rates studied monitoring consumption co-substrate oxygen, in catalyzed from two different fungi; Melanocarpus albomyces Trametes hirsuta , possessing molecular catalytic properties. rate studies compared physicochemical properties compounds: relative redox potentials determined cyclic voltammetry p K -values. Docking biphenylic active sites both performed resulting complex structures used further interpret results. Reaction mainly affected ability compound oxidized -value seems important. As consequence, with highest level redox-potential, vanillin, lower rate. Both type fit well laccases. Only compound, steric clashes observed, they likely an effect on When selected compared, redox-potential difference between T1 copper (Δ E ) not only property that In case selectivity specific laccase, reflected k cat / m value, plays important role.