Novel whey-derived peptides with inhibitory effect against angiotensin-converti...

• Author(s): Tavares, Tânia ; Del Mar Contreras, Maria ; Amorim, Manuela ; Pintado, Manuela ; Recio, Esidra ; Malcata, F. Xavier
• Date: 2011
• Persistent ID: http://hdl.handle.net/10400.14/7963
• Origin: Veritati - Repositório Institucional da Universidade Católica Portuguesa
• Subject(s): ACE-inhibitory peptide; Gastrointestinal digestion; Hydrolyzed whey; Antihypertensive activity
• Document Type: Article
• Language: English

Description

Whey protein concentrate (WPC) was subjected to enzymatic hydrolysis by proteases from the flowers of Cynara cardunculus, and the resulting angiotensin-converting enzyme (ACE)-inhibitory effect was monitored. The whole WPC hydrolysate exhibited an IC50 value of 52.9±2.9ºg/mL, whereas the associated peptide fraction with molecular weight below 3 kDa scored 23.6±1.1ºg/mL. The latter fraction was submitted to RP-HPLC, and 6 fractions were resolved that exhibited ACE-inhibitory effects. Among the various peptides found, a total of 14 were identified via sequencing with an ion-trap mass spectrometer. Eleven of these peptides were synthesized de novo – to validate their ACE-inhibitory effect, and also to ascertain their stability when exposed to simulated gastrointestinal digestion. Among them, three novel, highly potent peptides were found, corresponding to B-lactalbumin f(16–26) – with the sequence KGYGGVSLPEW, B-lactalbumin f(97–104) with DKVGINYW, and B-lactoglobulin f(33–42) with DAQSAPLRVY; their IC50 values were as low as 0.80±0.1, 25.2±1.0 and 13.0±1.0g/mL, respectively. None of them remained stable in the presence of gastrointestinal enzymes: they were partially, or even totally hydrolyzed to smaller peptides – yet the observed ACE-inhibitory effects were not severely affected for two of those peptides.