Enzymatic modification of wool with tyrosinase and peroxidase

The capabilities of tyrosinase and peroxidase to activate tyrosine residues of wool fibres and to catalyze crosslink formation between peptides derived from a wool protein hydrolyzate were investigated. Peroxidases were able to catalyse oxidation of wool fibres corresponding to 35–40% of the tyrosine residues located on the wool surface or 2% of the tyrosine residues in the wool fibre. Similar fibre surface modification was detected with tyrosinase and a fungal peroxidase using x-ray photoelectron spectroscopy. Tyrosinase did not show detectable activation of fibres measured as oxygen consumption. Tyrosinase was, however, able to crosslink peptides of 3–10 kDa derived from enzymatically hydrolysed wool fibres. Surprisingly, no crosslinking was detected with peroxidase.