Fig. 1. SDS-PAGE of HPI

Fig. 2. Size (a) and zeta-potential profiles (b) of HPI and SPI

Fig. 3. Circular dichroism (a), FTIR (b) and curve-fitting results of amide I band (c: HPI, d: SPI) of HPI and SPI

Fig. 4. Intrinsic fluorescence (a) and Ultraviolet spectrum (b). The illustration is ultravidet second derivative spectrum of HPI and SPI

Fig. 5. Effects of different pH on the intrinsic fluorescence of HPI

Fig. 6. Effects of different pH on the ultraviolet spectrum of HPI

Fig. 7. Effects of different pH on the size of HPI