CD spectroscopy measures the differences in the
absorption of the left handed polarized light versus a right
handed polarized light and can be used to determine the
proteins secondary structure in the far-UV spectral region
(190 – 250 nm). At these wavelengths, a chromophore is a
peptide bond, and a signal arises when it is located in a
regular, folded environment, -helix, -sheet and random
coil structures that provides characteristic shape and
magnitude of a CD spectrum. The negative peak at 208 nm
is characteristic of an -helix protein and a negative peak at
214 nm is characteristic of -sheet of protein27. CD curves
(Fig. 3b) of the IR extracted sericin sample in this study
show a negative band at 206–208 nm suggesting -helix
conformation. Gulrajani et al.18 found that sericin recovered
from HTHP degumming liquor shows a strong negative
band at 198 nm and a weak band at 218 nm suggesting
random coil and -sheet configuration respectively. On the
other hand, sericin recovered from alkaline degumming
shows a negative peak at 201 and 216 nm, revealing the
presence of -helix structure18. Wu et al.28 also reported
similar findings for the secondary structure of sericin