Abstract: Tyrosinases have the potential abilities of catalytic oxidation of tyrosine residues. In this paper, the efficacy of the 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 combinedly treated with tyrosinase and lactoferrin, the tensile strength of the silk fabric and its relative viscosity of fibroin solution seemed high as compared to that of the sample treated with loctoferrin alone, which verified the occurrence of the enzymatic grafting reaction on silk surface. Further, the loctoferrin might simultaneously adsorb onto fibroin during the mentioned enzymatic grafting, the color depth of the silk fabric treated with tyrosinases/loctoferrin was similar to that treated with loctoferrin alone.

Key words: tyrosinase, sild fibroin, lactoferrin, grafting