The laccase-assisted grafting of poly(tyrosine) was performed aiming to impart shrink-resistant properties to the wool materials. Laccase was able to efficiently catalyze the oxidation of tyrosine into dityrosine. When the reaction was performed using poly(ethylene glycol) (PEG) as template, the tyrosine oxidation gave rise to differentiated oxidation products, including di-, tri- and tetratyrosine, promoting also a higher grafting onto the wool fibers. The characterization of the grafted wool fibers and fabrics revealed some loss of crystallinity (about 4% of crystallization index) and thermal resistance (decreasing from 232 ºC to 224 ºC) resulting from the grafting process. However, the new bonds established between the new oxidation products and the amino groups of the wool, promoted an improvement, not only of the shrinkage properties (1.87% of area shrinkage), but also of their mechanical behavior (increasing by 45.28%). The strategy herein presented demonstrated potentiality to be applied as a “green” process for wool anti-shrinkage without compromising the fibers’ performance.

mercial ommercial hair perming uses strong reducing agents and is harmful to hair fiber’s quality even human health. In this study, tyrosine is adopted as a cross-linking agent between thiols as the shape-changing of hair involves breakage of disulfide bonds and the rearrangement of new bonds between keratin molecules. To investigate the mechanism of the cross-linking, bovine serum albumin (BSA) is used as a model protein. Molecular dynamics simulations give an insight on Cys solvent accessibility and protein stability for the wild type BSA and a designed BSA presenting the three broken disulfide bonds. A new cross-linked peptide, NECFLSHK-Tyrosine-Tyrosine-GACLLPK, inter- or intra- BSA monomers is formed, whose reactive cysteine residues are Cys-101 and Cys-176. Moreover, curling of Asian hair is conducted using tyrosine as a perming agent by laccase-assisted reaction. The optimized operational conditions are hair with cysteine pre-treatment (50.0 mM) followed by grafting with 3.0 mM tyrosine. The reshaped hair performed a better perming performance than commercial perming product before washing, although a lower perming efficiency after washing, however without strength loss and could be easily accomplished with a blow-drier. Hence, this new methodology may lead to the development of a gentle and user-friendly approach in the hair care industry.