抄録
Deterioration and yellowing of silk fibroin were hitherto controlled by methylation with diazomethane, but in this paper it is shown that the shrinkages of silk by neutral salts and mineral acid solutions may be remarkably diminished. The causes of the shrinkage control of silk by methylation with diazomethane are also discussed on the bases of our experiments and many data attributing to the methylation of phenolic hydroxyl groups of tyrosine residues are proposed. Tyrosine residues of silk fibroin are, it is concluded, responsible for the shrinkage phenomena of silk by salts and acids; this conclusion coincides with the preceding study by R. Murase.
