Submitted to: Journal of Dairy Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/20/2015
Publication Date: 5/1/2016
Publication URL: http://handle.nal.usda.gov/10113/62621
Citation: Paul, M., Phillips, J.G., Renye Jr, J.A. 2016. Short communication: Measuring the angiotensin-converting enzyme inhibitory activity of an 8-amino acid (8mer) fragment of the C12 antihypertensive peptide. Journal of Dairy Science. 99(5):3263-3266. doi: 10.3168/jds.2015-10437.
Interpretive Summary: Being able to increase the nutritional and health-promoting properties of food using milk-derived ingredients is a challenge that has attracted a great deal of attention recently. Many bioactive compounds derived from milk proteins exhibit potential as functional food ingredients aimed at combating various conditions that can be controlled through diet, such as cardiovascular disease, type II diabetes and obesity. Previous research explored the possibility of incorporating a small peptide (C12 peptide) that helps reduce blood pressure into milk products such as yogurt. It was found that it is broken down by the starter cultures used for fermentation into a smaller 8 amino acid (8mer) peptide that is stable under yogurt-making conditions. This research addresses the question of whether the 8mer peptide retains the same biological activity exhibited by the parent C12 peptide. We have synthesized and purified the 8mer peptide in house and assessed its antihypertensive activity. Our results indicate that it does indeed retain biological activity and that it remains stable in the presence of starter cultures. The 8mer peptide now has the potential to be used as a health-promoting functional ingredient in many fermented dairy foods.
Technical Abstract: An eight amino acid fragment (PFPEVFGK) of a known milk protein-derived antihypertensive peptide was synthesized by microwave-assisted solid phase peptide synthesis and purified by reverse phase HPLC. Its ability to inhibit the angiotensin-converting enzyme was assessed and compared to that of the parent 12mer peptide (FFVAPFPEVFGK) to determine the effect of truncating the sequence on the overall hypotensive activity. The activity of the truncated 8mer peptide was found to be almost 1.5 times less active than the 12mer, with IC50 values of 108 and 69 uM, respectively. The overall activities of both the 12mer and the 8mer, however, are in the range of being physiologically important and potentially active following oral administration, and therefore may have potential use as a blood pressure lowering agent in humans in the future.