Hiromitsu SUGAKAWA and colleagues at RIKEN Bioresources Research Center have treated an aqueous silk protein solution with tyrosinase, thereby converting tyrosine residues in silk to DOPA. Amino acid analysis by ninhydrin confirmed that the treated silk contained about 1 mol% of DOPA. The adhesiveness of this DOPA-containing silk protein was greatly improved, especially under basic conditions, probably by interaction between deprotonated lysine and DOPA, as with mussel adhesion protein. DOPA-silk also showed high adhesion to paper, polypropylene resin, wood and silk thin film.

RIKEN news release, March 11, 2019