Tyrosinase-catalyzed modification of silk fibroin by grafting of lactoferrin

Since tyrosinases have the potential abilities of catalytic oxidation of tyrosine residues,the efficacy of enzymatic grafting of lactoferrin onto silk fibroin with tyrosinase was investigated. The changes of tyrosine content in silk fibroin and the relative viscosity of silk fibroin solution were also evaluated. The results indicated that the content of tyrosine in silk fibroin decreased after incubating with tyrosinase. For the sample treated with tyrosinase / lactoferrin,the tensile strength of the silk fabric and the viscosity of fibroin solution increased,which verified the occurrence of the enzymatic graft reaction on silk surface. Furthermore,the loctoferrin might simultaneously adsorb onto fibroin during above-mentioned enzymatic grafting,and the dyeing behavior of the silk fabric treated with tyrosinases / loctoferrin was similar to that treated with loctoferrin alone.