蚕蛹蛋白及其水解产物中氨基酸组成分析

采用FMOC-OPA柱前衍生化-高效液相色谱法测定蚕蛹蛋白及水解液氨基酸含量,同时测定血管紧张素转化酶(ACE)抑制活性,研究蚕蛹蛋白水解后氨基酸组成的改变及对ACE抑制活性的影响。结果表明:水解液10kD以下组分(SN2)中疏水性氨基酸含量为49.15%,显著高于10kD以上组分(SN1)中的40.55%及蚕蛹蛋白中的45.21%,其中对ACE抑制活性影响较大的脯氨酸、芳香族氨基酸含量为7.75%和19.20%,高于SN1中的5.62%和13.59%及蚕蛹蛋白中的7.42%和15.81%,并且SN2中ACE抑制率为47.6%显著高于SN1和蚕蛹蛋白中的抑制率,表明水解后疏水性氨基酸组成的改变与ACE抑制活性的变化趋势相同,且ACE抑制活性主要集中于SN2。

Amino Acid Compositions of Silkworm Pupa Protein and Its Hydrolysates

The amino acid compositions of silkworm pupa protein and its hydrolysates prepared with neutral protease were determined by reversed-phase high performance liquid chromatography(RP-HPLC) with precolumn derivatization.Meanwhile,their ACE inhibitory activity was also tested.The results indicated that the content of hydrophobic amino acids in the hydrolysate ultrafiltration fraction SN2(< 10 kD) was 49.15% compared to 40.55% for the hydrolysate ultrafiltration fraction SN1(>10 kD) and 45.21% for silkworm pupa protein.The contents of proline and aromatic amino acids(Trp,Phe and Tyr),which had great effect on ACE inhibitory activity,were 7.42% and 15.81%,respectively.Moreover,the ACE inhibitory rate of SN2 was 47.6%,which was remarkably higher than that of SN1 and silkworm pupa protein,suggesting that the change trends of hydrophobic amino acid composition and ACE inhibitory activity are the same and that the ACE inhibitory activity is mostly concentrated on SN2.