发酵乳中血管紧张素转换酶抑制剂的分离与鉴定

用瑞士乳杆菌生产具有抑制血管紧张素转换酶(ACE)活性的发酵乳并从其中分离血管紧张素转换酶抑制剂(ACEI)。脱脂乳经灭菌后,接种4%(V/V)的发酵剂,37℃培养24h,获得抑制ACE活性较高的发酵乳。对此发酵乳的乳清进行超滤、上海732阳离子树脂交换、SephadexG-15凝胶过滤和HPLC分步纯化,最终得到两种起主要作用的ACEI肽。经氨基酸分析和液相-质谱分析,这两种肽的氨基酸序列分别为:Phe-Pro(IC50:12.05μmol/L)和Ala-Glu-Glu(IC50:12.42μmol/L)。

Isolation and Identification of Angiotensin Converting Enzyme Inhibitors from Fermented Milk

To produce fermented milk that can inhibit the activity of angiotensin converting enzyme(ACE), then the angiotensin converting enzyme inhibitor(ACEI) can be purified from the fermented milk. Skim milk was sterilized at 115℃ for 15min, inoculated with 4%(V/V)starter containing L. helveticus, and fermented at 37℃ for 24h. Finally, the fermented milk was obtained with rather high inhibitory activity to ACE. From the whey of fermented milk, two kinds of ACEI pepetides of most functions were purified by using ultrafilter, cation exchange with shanghai 732, gel filter with Sephadex G-15 and several step HPLC. The structures of two peptides were Phe-Pro and Ala-Glu-Glu respectively determined by LC/MS and amine acid composition, and the concentrations of peptides needed to inhibit 50% of ACE activity (IC50) were 12.05μmol/L and 12.42μmol/L, respectively.