血管紧张素转换酶抑制肽的分离

Separation of angiotensin converting enzyme inhibitor peptides

采用截留分子量分别为30 ku、10 ku、6 ku、3 ku的中空纤维超滤膜对扇贝酶解产物进行分级分离,并结合凝胶柱层析分离技术测定了各分离组分的分子量分布,同时还测定了各分离组分对血管紧张素转换酶(ACE)的抑制活性。实验结果表明,不同截留分子量超滤膜可以实现酶解产物按其分子量大小的分级分离,不同分离组分的ACE抑制力活性差异较大,总趋势是截留分子量相对较小的超滤膜透过液的ACE抑制活性较强。其中,截留分子量为3 ku超滤膜的透过液具有最强的ACE抑制活性,其ACE抑制率I(%)=96.17%,半抑制浓度IC_(50)= 0.078 mg·mL^(-1)。通过对截留分子量为3 ku超滤膜的透过液依次经过Sephadex G-25及Sephadex G-15凝胶柱层析分离纯化后,分离出了ACE抑制活性最强的2个组分活性肽,其平均分子量分别为1 300 u和900 u左右,其IC_(50)分别为0.026 mg·mL^(-1)和0.012 mg·mL^(-1)。

Separation effect of protein hydrolysates by ultrafiltration membrane system with 3 000, 6 000, 10 000, 30 000 Daltons molecular-weight-cut-off（MWCO） membranes, and the inhibitory ability（ I% ） of angiotensin converting enzyme （ACE） of filtrate fraction by Sephadex G-25 and Sephadex G-15 filtration chromatography were investigated, respectively. The results showed that different composition could be separated from hydrolysates with different MWCO membranes and different size peptide had great different ACE inhibitory ability. The smaller MWCO of ultrafiltration membranes, the higher ACE inhibitory ability of the fraction. The filtrate from the 3 000 Daltons MWCO membrane had a much higher ACE inhibitory ability, I（% ） = 96. 17% and IC50 = 0. 078 mg· mL^-1, than that from other MWCO membranes. The average molecular weight of two group peptides separated by Sephadex G-25 and Sephadex G-15 filtration chromatography followed by separation from the hydrolysates with 3 000 Daltons MWCO membrane, whichpossessed the highest ACE inhibitory ability （IC50 0. 026 mg·mL^-1 and 0. 012 mg·mL^-1）, were 1 300 and 900 Daltons, respectively.