Comparison of physical–chemical properties of type I collagen from different species

Type I collagen is an important biopolymer and has been widely used in biomaterials due to its excellent biocompatibility and biodegradable properties. However, only a few studies have been reported on its comparison in different species. The amino acid composition, SDS-PAGE, UV–Vis spectrum, thermal transition temperatures, extractable uronic acid/protein ratio and enzymatic sensitivity of type I collagen from bird feet (BF), bovine skin (BS), frog skin (FS), porcine skin (PS) and shark skin (SS) were evaluated. The amino acid composition of type I collagens were different from different species, BF collagen contained higher glutamic acid (Glu) and aspartic acid (Asp), SS collagen contained lower aspartic acid and hydroxyproline (Hyp). Similar SDS-PAGE profiles were found from different animal’s collagen, all samples were composed of two α1-chain and one α2-chain. All UV–Vis spectrums exhibited a typical absorption peak at 218 nm. The UV absorption spectrum of BF collagen ranged from 190 to 340 nm, FS collagen ranged from 190 to 270 nm; the other species collagen ranged from 190 to 240 nm. Thermal transition temperatures of type I collagen from different animals decreased in the order of BF > BS > PS > FS > SS. PS collagen had higher extractable uronic acid/protein ratio and the lowest enzymatic sensitivity. Summarizing these results, the BF collagen had higher hyproxyproline (Hyp) + proline (Pro) value and exhibited higher thermal stability; the PS collagen contained larger amount of glycosaminoglycan and resulted in a high enzymes resistance. However, the BF and PS collagen should be used as a suitable material in biomaterial utilitys because of its better biostability.