Ethylenediamine tetraacetic acid edta sodium salt

Xanthine oxidase 0.39 U·mg⁻¹ and cellulose acetate were supplied by Fluka AG (Buchs, Switzerland). 2,2′-Azobis(2-amidinopropane) dihydrochloride (AAPH) was supplied by Waco Chem (Richmond, VA, USA). Potassium dihydrogenphosphate, sodium acetate and sodium hydrogenphosphate were supplied by Carlo Erba (Milan, Italy). Polyvinylacetate, acid-2-carboxy-6-hydroxy-2,5,7,8-tetramethylchroman (Trolox) was supplied by Aldrich (Steinheim, Germany). Xanthine (2,6-dihydroxypurine) sodium salt, N,N-dimethyl-p-phenylenediamine, ethylenediamine tetraacetic acid (EDTA) sodium salt, superoxide dismutase 4980 U·mg⁻¹, ferric chloride, dialysis membrane (art. D-9777), and β-phycoerythrin were supplied by Sigma (Milan, Italy).

Chestnut tannins (CT) and quebracho tannins (QT) were provided by Silvateam (S. Michele Mondovì, Cuneo, Italy).
Whatman^® Nylon membrane filters (0.45 μm pore size, 47 mm diameter) were from Sigma-Aldrich (Milan, Italy).
2,2-Diphenyl-1-picrylhydrazyl (DPPH), iron (III) chloride hexahydrate (97%), iron (II) chloride tetrahydrate, iron (II) sulfate, 2,4,6-tris(2-pirydyl)-s-triazine (TPTZ) (≥98%), (±)-6-hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid (Trolox) (97%), sodium borohydride, and ethylenediaminetetraacetic acid (EDTA) sodium salt were obtained from Sigma-Aldrich (Milan, Italy) and used as obtained.
The laccase used in this study was the recombinant POXA1b from the fungus Pleurotus ostreatus heterologously produced in the yeast Pichia pastoris [28 (link)].
UV-Vis spectra were recorded using a HewlettPackard 8453 Agilent spectrophotometer.
Chemical structures were drawn with the software ChemDraw Ultra 12.0.