9种市售阿胶蛋白质特性比较分析

Comparison and analysis of the protein characteristics in 9 kinds of commercial Asini Corii Collas

对9种市售阿胶（E1～E9）进行蛋白质特性分析比较，包括氨基酸组成、等电点、二级结构和分子量分布。结果表明，9种市售阿胶的蛋白质等电点均在4．38～4．88，无明显差异；圆二色谱表明所有样品中蛋白质的三螺旋结构均被破坏，呈无规则卷曲状态；氨基酸组成大致相似，而亚氨基酸（脯氨酸和羟脯氨酸）组成有一定差异，E2、E3、E4、E9的亚氨基酸含量较低，小于23．8％，其余5种样品的含量较高，大于25．0％；蛋白质分子量分布有较大差异，E2、E4、E7、E8的阿胶蛋白质分布更分散，含有较多的高分子蛋白（占比〉4．46％），且主要蛋白质的重均分子量较大，为120～132kD，而其余5种样品的分子量分布较集中，高分子蛋白占比小于1．16％，且主要蛋白质的重均分子量较小，为36～42kD。市售阿胶的蛋白质差异主要是蛋白质的降解程度不同造成的。阿胶差异化评价的蛋白质特性评价，为进一步考察工艺对蛋白质特性的影响提供依据。

The protein characteristics of 9 kinds of commercial Asini Corri Collas （ACC, E1 E9） were compared, including amino acid composition, pI, secondary structure and molecular weight distribu- tion. The differences of pI were negligible and all samples showed a range of 4.38-4.88. Circular dichroism results indicated that only random coil configurations was observed of all ACC samples due to the damage of triple helix structures. The amino acid composition was similar other than some differences in imino acid （Pro and Hyp） composition. F2, E3, E4 and E9 showed lower imino acid content （ 〈23.80%） than that of others （ 〉 25.0%）. Significant differences in the molecular weight distribution were observed. E2, E4, E7 and E8 appeared to be in a wider distribution containing more high molec ular weight （〉4.46%） and the major MW fraction was located in the range of 120-132 kD. The other 5 samples, however, showed a nar rower distribution （ high molecular weight protein 〈1.16% ） and the major MW fraction was located in the range of 36-42 kD. The difference in protein characteristics of commercial ACC attributed to the differences in degradation degree of protein. This study would im prove the protein characteristics evaluation system of ACC and lay a foundation to further study the effect of processing on protein charac- teristics.