Study on physico-chemical and enzymatic properties of collagen from shark skin and tilapia skin

To compare collagen properties of deep sea fish with fresh water fish, the acid soluble collagen was extracted from shark skin and tilapia skin, and their physico- chemical and enzymatic properties were investigated. The amino acid composition showed that the isoleucine content of shark skin collagen was about2-fold higher than that of tilapia skin collagen, but the proline content was lower. The molecular weight of αchain and β chain, and the thermal denaturation temperature of shark skin collagen were lower than those of tilapia skin collagen. However, no difference was observed in the FTIR and UV-Vis spectra. On the other hand, the data of SDS-PAGE and HPLC were indicated that both shark skin collagen and tilapia skin collagen could be hydrolyzed more easily by collagenase or trypsin than papain. When collagen was hydrolyzed with collagenase (enzyme-to-substrate ratio, 0.05∶100) at pH8.0 and 50℃ for 240 min, the collagen peptide content with molecular weight below 1000 u from shark skin reached up to 23%, but only 17% was found in the tilapia skin collagen peptide.