Radical mediated indirect oxidation of a PEG-coupled polycyclic aromatic hydrocarbon (PAH) model compound by fungal laccase

A high molecular model compound of polycyclic aromatic hydrocarbon was synt hesised by coupling pyrene to PEG(5000). The pyrene-PEG was used for the st udy of a laccase-mediator-system. To prevent direct contact between the sub strate and the enzyme the two were kept in their own compartments separated by a membrane. The low molecular mediators, 1-hydroxybenzotriazole and 2,2 '-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid), which were oxidised by laccase to the corresponding radicals or cations permeated the membrane and reacted with the pyrene-PEG model compound. Oxidation of the model comp ound resulted in an alpha-oxidation of the alkyl-chain leading to two main oxidation products. The same oxidation products were obtained in the reacti on system without a membrane. (C) 2000 Elsevier Science B.V. All rights res erved.