Abstract: In this study, different reagents were chosen to extract collagen from channel catfish skin and partial characteristics of the collagen were ivestigated. The results showed that under the condition of 4 ℃, soaking the fish skins with 0.1mol/L NaOH for 6 hfollowed by with 2.5% NaCl for 6 h, can remove non-collagens better than soaking with NaOH and NaCl alone or commonly.Then the fish skins are soaked with 10% butyl alcohol to remove lipids. Finally the skins are extracted to obtain collagen with 0.1 mol/L citric acid for 3 days. The extraction rate of collagen is 34.67% and the collagen is colorless and tasteless. The collagen contains more than 21.19% glycine, and its denaturation temperature is 50.2 ℃. SDS-PAGE showed that the collagen is composed of two a chains, and the content of b chain is higher. The collagen has high viscosity, which increases as the concentration of the collagen rising .

Key words: channel catfish, skin, collagen, extraction reagent, amino acid, viscosity, denaturation temperature