Table 2. The Raman peak potions and tentative assignments of major vibration bands.

Peak positions (cm−1)	Tentative assignments
620	Phenylalanine: C-C twisting mode
643	Tyrosine: C-C twisting mode
760	Tryptophan: ring breathing
828	Tyrosine: ring breathing;
854	Tyrosine: ring breathing
878	Hydroxyproline; Tryptophan
936	proline/valine/protein backbone (α-helix conformation): C-C stretching mode
1004	Phenylalanine: ring breathing
1031	Phenylalanine: C-H in-plane bending mode
1048	Protein: C-N / C-O stretching mode
1126	Protein: C-N stretching vibration
1207	Hydroxyproline; Tyrosine
1260	Amide III
1340	Tryptophan: CH2/CH3 wagging, twisting and/or bending mode
1446	Proteins: CH2 bending mode
1552	Tryptophan: C = C stretching mode
1685	Amide I