Preparation and characterisation of type I and V collagens from the skin of Amur sturgeon (Acipenser schrenckii)

The collagen in Amur sturgeon was extracted by pepsin digestion and separated into two fractions, P2.4 (92.40%) and P4.0 (2.16%), by sodium chloride precipitation. SDS–PAGE and amino acid profile suggested that the P2.4 and P4.0 might be classified as type I collagen (PSC-I) and type V collagen (PSC-V), respectively. These collagens appeared to be dense sheet-like film linked by random-coiled filaments under SEM. The denaturation and melting temperatures of PSC-V (35.92 and 122.86 °C) were significantly higher than PSC-I (32.52 and 116.01 °C) assessed by CD and DSC, which could be attributed to its higher imino acid content (23.43%) and degree of hydroxylation (52.18%). FTIR confirmed their triple helical structure, and indicated more intermolecular crosslinks in PSC-I and more hydrogen bond in PSC-V. These results provide some basis for their large-scale production and further application as alternatives to mammalian collagen.