A simple method has been developed for the isolation of Acid Soluble Collagen (ASC) and Pepsin Digestible Collagen (PDC) from the skin of Albacore tuna (Thunnus alalunga), Dog shark (Scoliodon sorrakowah), and one among Indian Major Carps ie, Rohu (Labeo rohita). Biochemical characterization of the collagen extracted was carried out. On wet weight basis the yields of ASC and PDC from shark skin were 8.96% & 7.68% respectively and that from Rohu was ASC 4.13% & PDC 3.68% respectively. The yield of collagen from Tuna skin was ASC 13.97%. No PDC was obtained for tuna skin. Proximate analysis showed all collagens had protein as a major constituent with trace amount of ash and fat. Amino acid analysis revealed that they contained glycine as a major amino acid with high contents of alanine, proline and hydroxyproline. Based on sodium dodecyl sulfate – polyacrylamide gel electrophoretic patterns and subunit compositions, all were identified to be type 1 collagens. A comparison of these collagens with calf skin type 1 collagen indicated the same and α1,α2 and β chains were the major components of these collagens. γ components were also found in lesser amounts in these collagens. The results of the present study indicated that comparing the three species Dog shark skin had good yield of collagen and it could be served as an alternative source of collagen for different biomedical applications.
