Profile

PhD student

Project: Direct-Affinity Reverse Extraction (DARE) screening for bioactive food-derived peptides

To develop a high-trough-put screening concept for identification of food components, particularly peptides, that bind to protein targets of relevance for human health.

To establish appropriate bioassays for assessment of the effect of the identified peptides using milk as our model food and immune function as our biological target.

To develop preparative methods for purification of specific, bioactive peptides from milk.

Foods of the future should provide not only appropriate nutrients and sufficient energy for human function but also contribute to the well-being and health of consumers. The existence of bioactive, non-nutrients in various foods, particularly milk, has been documented extensively. Milk is the first and exclusive food for newborn mammals, and it seems reasonable to assume that milk has been perfected during the more than 250 million years of mammal evolution not only as a complete nutrient but also to ensure optimal health. Thus, a number of immune functions of specific milk proteins have been described, from passive immunity provided by intestinal absorption of milk immunoglobulins to antibacterial and antiviral effects of other proteins, e.g. lactoferrin, lactoperoxidase, and lysozyme to mention a few.

Bioactive milk-derived peptides
Bioactive peptides can be derived from milk proteins by proteases through passage of the gastrointestinal (GI) tract of the consumer or by proteases added for processing of milk into various dairy products. There has been much focus for several years on bioactive peptides from milk proteins exerting various physiological effects, such as antibacterial, -viral, -hypertensive, or with endorphine-like activity.
We believe therefore that future research efforts should focus on identification of peptides of high biological potency only, i.e. high binding affinity towards relevant target proteins, and therefore more likely to exert a biological effect. We have conceived a conceptual strategy to accomplish this.

  DARE-screening for bioactive peptides
Bioactive peptides have hitherto been identified and characterized through classical biochemical fractionation/ purification of hydrolysates and repeated testing in bioassays. This is a time- and resource costly process. We propose to identify bioactive peptides by Direct Affinity Reverse Extraction (DARE), arguing that for a peptide to have a biological effect it must bind to a relevant target protein with high affinity. This novel method utilizes immobilized target proteins to extract peptides with high binding affinity from complex hydrolysates containing thousands of different peptides. Target proteins will be selected based on their biological function and potential relevance in specific bioassays. Peptides with different affinity can then be selected using various washing procedures. Further, the method employs purified target proteins immobilized directly on MALDI-TOF plates for subsequent identification by accurate mass analysis and sequencing of selected peptides by fragmentation MS/MS analysis. The analytical process can be automated for high-throughput capacity.