Tyrosinase-catalysed coupling of functional molecules onto protein fibres

Grafting, using oxidative enzymes shows a high potential for wool fibres functionalisation. In this work we attempt to graft on wool fibres with phenolic antioxidants in order to introduce and improve the properties of the fibre. The approach of tyrosinase to oxidize tyrosine residues in wool proteins to quinones, which can further react with free sulfhydryl (thiol), amino or phenolic groups of different substrates was exploited to couple different phenolic antioxidants (caffeic acid and chlorogenic acid) onto the wool fibre proteins. Tyrosinase-catalysed reactions were followed by different analytical methods like oxygen consumption, FT-NIR Raman and UV/vis spectroscopy. It was proved that phenolic compounds used are strongly cross-linked on the wool fibre resulting to an improved antioxidant activity.