title: Oxidation of the erythro and threo forms of the phenolic lignin model compound 1-(4-hydroxy-3-methoxyphenyl)-2-(2-methoxyphenoxy)-1,3-propanediol by laccases and model oxidants.
abstract: Mixtures of equal amounts of the erythro and threo forms of the phenolic arylglycerol beta-aryl ether 1-(4-hydroxy-3-methoxyphenyl)-2-(2-methoxyphenoxy)-1,3-propanediol were oxidized (i) with laccases from Trametes versicolor, Agaricus bisporus, Myceliophthora thermophila and Rhus vernicifera, (ii) with laccase-mediator systems consisting of T. versicolor laccase and ABTS or HBT, and (iii) with various model oxidants including cerium(IV) ammonium nitrate (CAN), lignin peroxidase, Fenton's reagent, and lead(IV) tetraacetate (LTA). All the laccases exhibited a similar preferential degradation of the threo form. The mediator ABTS counteracted the threo preference of laccase, but the mediator HBT did not affect it. The outer-sphere model oxidants CAN and lignin peroxidase showed a preferential degradation of the threo form. LTA and Fenton's reagent did not exhibit any stereo-preference. The results suggest that laccases of different origin, primary structure, and redox potential behave as typical outer-sphere oxidants in their interaction with the diastereomers of the arylglycerol beta-aryl ether.
authors: Department of Chemistry and Biomedical Sciences, Karlstad University, SE-651 88 Karlstad, Sweden.
authors: Christina
authors: C
authors: Bohlin
authors: Knut
authors: K
authors: Lundquist
authors: Leif J
authors: LJ
authors: Jönsson
mesh_terms: D006140:Guaifenesin / Q000031:analogs & derivatives; D042845:Laccase / Q000737:chemistry*; D008956:Models, Chemical; D016877:Oxidants / Q000737:chemistry*; D010084:Oxidation-Reduction; D011409:Propylene Glycols / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet
chemical_list: D016877:Oxidants; D011409:Propylene Glycols; D006140:Guaifenesin; C046052:guaiacylglycerol-beta-guaiacyl ether; D042845:Laccase