Short communication: Inhibition of angiotensin 1-converting enzyme by peptides derived from variants of bovine β-casein upon apical exposure to a Caco-2 cell monolayer

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• 作者：Bj&oslash ; rn Petrat-Melin ; Thao T. Le ; Hanne S. M&oslash ; ller ; Lotte B. Larsen ; Jette F. Young ; ^{jettef.young@food.au.dk}
• 关键词：angiotensin 1-converting enzyme ; beta-casein ; bioactive peptide ; genetic variant ; in vitro digestion
• 刊名：Journal of Dairy Science
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：100
• 期：2
• 页码：881-885
• 全文大小：310 K
• 卷排序：100

文摘

This study investigated the consequence of genetically contingent amino acid substitutions in bovine β-casein (CN) genetic variants A1, A2, B, and I on the structure and bioactive potential of peptides following in vitro digestion. The β-CN variants were digested in vitro using pepsin and pancreatin, and a peptide profile was obtained by liquid chromatography tandem mass spectrometry, revealing among others, the β-casomorphin precursor peptides VYPFPGPIHN and VYPFPGPIPN, derived from variant A1/B and from A2/I, respectively. These 2 peptides were synthesized and assessed for angiotensin 1-converting enzyme (ACE) inhibitory capacity before and after incubation with a monolayer of Caco-2 intestinal cells. The VYPFPGPIHN was a stronger ACE inhibitor than VYPFPGPIPN, with the concentration needed to reach half-maximal inhibition (IC50) of 123 ± 14.2 μM versus 656 ± 7.6 μM. Exposure to a Caco-2 intestinal cell monolayer did not affect ACE inhibition by VYPFPGPIHN, but resulted in an almost 2-fold increase in inhibition by VYPFPGPIPN after incubation. Subsequent tandem mass spectrometric analysis identified the truncated peptide VYPFPGPIP, suggesting hydrolysis by a cell membrane associated peptidase. Thus, genetic variation in bovine β-CN results in the generation of peptides that differ in bioactivity, and are differently affected by intestinal brush border peptidases.