shown in Fig. 1
-The pKa value resulting from the Try OH deprotonation is 10.4
and the electric repulsion among Try O− groups occur.
-As a result, the viscosity of the silk fibroin aqueous solution
-decreases considerably at pH 10.4 and we can prepare
such a solution with high concentration 30% (w/v) in the stable state.
-The 13C solution NMR spectrum of B. mori silk fibroin prepared
from cocoons in aqueous solution at pH 10.4
-There are no chemical shift difference of Ala, Gly and Ser
peaks between random coil and Silk I,
but the peaks should be considerably broader
for Silk I compared with random coil.
-The sharpness of the peaks in Fig. 1
indicates that the conformation of silk fibroin is random coil and not Silk I.