Abstract
The heterogeneous addition reaction of silk fibroin fibers from Dictyoploca Japonica, Antheraea pernyi, Antheraea yamamai, Philosamia cynthia recini and Bombyx mori with various monoepoxides was investigated using ethanol after the fibers were padded with aqueous solution of salt as catalyst. The reactivity of the main functional amino acid residues was found to decrease in the order of lysine>histidine>tyrosine>arginine. The reaction of tyrosine and histidine depended on both the polar and steric factors of the substituents of the epoxides. Their effect was analyzed by using the modified Taft's equation. The difference in the reactivity of tyrosine, arginine, histidine among these wild and domestic silk fibroins to the epoxides was partly ascribed to the swelling and intermicellar distance, as well as the amino acid composition of the fibroin fibers.
