鲨鱼皮胶原与罗非鱼皮胶原的理化性质及酶解特性研究

Study on physico-chemical and enzymatic properties of collagen from shark skin and tilapia skin

为了系统比较深海鱼和淡水鱼胶原的差异,利用酸法提取鲨鱼皮胶原和罗非鱼皮胶原,并对它们的理化性质和酶解特性进行了考察。氨基酸组成分析表明,鲨鱼皮胶原中异亮氨酸含量大约是罗非鱼皮胶原的2倍,但脯氨酸含量较少。鲨鱼皮胶原α肽链和β肽链的分子量,以及胶原热变性温度都低于罗非鱼皮胶原,但在紫外光谱和红外光谱中没有发现明显的差异。另一方面,电泳图谱和液相图谱都表明,鲨鱼皮胶原和罗非鱼皮胶原容易被胶原酶和胰蛋白酶酶解,不易被木瓜蛋白酶酶解。在胶原酶与底物质量比为0.05%,pH8.0和50℃的酶解条件下,经过240min酶解,鲨鱼皮胶原肽中小于1000u的肽含量达到23%,而罗非鱼胶原肽中却只有17%。

To compare collagen properties of deep sea fish with fresh water fish,the acid soluble collagen was extracted from shark skin and tilapia skin, and their physico-chemical and enzymatic properties were investigated. The amino acid composition showed that the isoleucine content of shark skin collagen was about 2-fold higher than that of tilapia skin collagen,but the proline content was lower. The molecular weight of chain and β chain,and the thermal denaturation temperature of shark skin collagen were lower than those of tilapia skin collagen. However,no difference was observed in the FTIR and UV-Vis spectra. On the other hand, the data of SDS-PAGE and HPLC were indicated that both shark skin collagen and tilapia skin collagen could be hydrolyzed more easily by collagenase or trypsin than papain. When collagen was hydrolyzed with collagenase（enzyme-to-substrate ratio,0.05：100） at pH8.0 and 50% for 240min,the collagen peptide content with molecular weight below 1000u from shark skin reached up to 23%,but only 17% was found in the tilapia skin collagen peptide.