Abstract: Collagens are attracting attentions recently because of their unique characteristics. Until now the main sources of industrial collagen are limited to those from skin and bone of land animals such as bovine and porcine. However,these animals may have the risk of infection of BSE (boving spongiform encephalopathy) or FMD (foot and mouth disease). Actually,a large amount of collagen exists in the wastes of aquatic animals such as in fish skin and bone and most importantly such collagens have biological safety. Therefore,studies on collagens from fish bone will deliver essential research data for collagen utilization. In this paper,the extraction and purification of bone collagens from four species of fish,including shark,silver carp,grass carp and tilapia were studied. The extraction and purification were carried out by a series of steps involving removing non-collagenous proteins with 0.1mol/L sodium hydroxide,decalcifing with 0.5mol/L EDTA,removing fat with 10% iso-propanol,extracting collagen with 0.5mol/L acetic acid and salting out with sodium chloride. SDS-PAGE revealed that extracted collagens were of high purity and the purity of shark bone collagen was the highest. All four bone collagens could be degraded at 37℃ by porcine trypsin and at 50℃ by proteinase K. The result showed that the method of enzymatic degradation adopted were effective and the hydrolyzed products were of different molecular weights. Peptide mapping analysis revealed that bone collagen from one fish specie was different from that of bone collagens from other fish species. More distant the fish species were,more different the peptide maps were. Amino acid composition analysis revealed that glycine was the most abundant amino acid residue in both shark and silver carp bone collagens,with alanine the second,glutamic acid the third and arginine the fourth.

Key words: fish bone, collagen, purification, characteristic