Article

In vitro generation and stability of the lactokinin beta-lactoglobulin fragment (142-148).

Department of Life Sciences, University of Limerick, Ireland.
Journal of Dairy Science (Impact Factor: 2.55). 12/2004; 87(11):3845-57. DOI: 10.3168/jds.S0022-0302(04)73524-9
Source: PubMed

ABSTRACT The objectives of this study were to investigate the generation of beta-lactoglobulin fragment (142-148) (beta-LG f(142-148) during the hydrolysis of whey proteins, and the in vitro stability of this fragment upon incubation with gastrointestinal and serum proteinases and peptidases. An enzyme immunoassay (EIA) protocol was developed for the quantification of beta-LG f(142-148) in whey protein hydrolysates and in human blood serum. The minimum detection limit was 3 ng/mL. The level of the peptide in whey protein hydrolysates was influenced by the degree of hydrolysis (DH). As expected, highest levels of this peptide were found in hydrolysates generated with trypsin. Sequential incubation of hydrolysates at different DH values with pepsin and Corolase PP, to simulate gastrointestinal digestion, generally resulted in the degradation of beta-LG f(142-148) as determined by EIA. Reversed-phase HPLC and angiotensin-I-converting enzyme (ACE) activity assays demonstrated that synthetic beta-LG f(142-148) was rapidly degraded upon incubation with human serum. Furthermore, beta-LG f(142-148) could not be detected by EIA in the sera of 2 human volunteers following its oral ingestion or in sera from these volunteers subsequently spiked with beta-LG f(142-148). These in vitro results indicate that beta-LG f(142-148) is probably not sufficiently stable to gastrointestinal and serum proteinases and peptidases to act as an hypotensive agent in humans following oral ingestion. The in vitro methodology described herein has general application in evaluating the hypotensive potential of food protein-derived ACE inhibitory peptides.

0 Followers
 · 
107 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: Dipeptidyl peptidase (DPP)-IV inhibitory peptides were purified and identified from an aqueous Palmaria palmata protein extract hydrolysed with Corolase PP. The hydrolysate was fractionated by solid phase extraction (SPE) using a C18 matrix followed by semi-preparative reverse phase-high performance liquid chromatography (SP RP-HPLC). IC50 values of 1.47 ± 0.09, 0.54 ± 0.03 and 0.36 ± 0.03 mg/ml were obtained for the hydrolysate, the 25% – acetonitrile (ACN) SPE fraction and the most active SP RP-HPLC peptide fraction (SP RP-HPLC 25_F28), respectively. Thirteen peptide sequences were identified following UPLC–ESI MS/MS analysis of SP RP-HPLC 25_F28. Three novel DPP-IV inhibitory peptides, Ile-Leu-Ala-Pro, Leu-Leu-Ala-Pro and Met-Ala-Gly-Val-Asp-His-Ile, with IC50 values in the range 43–159 μM were identified. The results indicate that P. palmata derived peptides may have potential as functional food ingredients in the prevention and management of type 2 diabetes.
    Food Chemistry 04/2015; 172:400–406. DOI:10.1016/j.foodchem.2014.09.083
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Abstract Year to year obesity prevalence, reduced physical activities, bad habits/or stressful lifestyle, and other environmental and physiological impacts leading to increase of diseases such as coronary heart disease, stroke, cancer, diabetes and hypertension worldwide. Hypertension is considered as one of the most common serious chronic diseases; however, discovery of medications with high efficacy and without side effects for treatment of patients remains a challenge to scientists. Recent trends in the functional foods have evidenced that food bioactive proteins play a major role in the concepts of illness and curing: therefore, nutritionists, biomedical scientists, and food scientists are working together to develop improved systems for discovery of peptides with increased potency and therapeutic benefits. This review presents the recent research carried out to date for purposes of isolation and identification of bioactive hydrolyzates and peptides with angiotensin I-converting enzyme (ACE) inhibitory activity and antihypertensive effect from animal, marine, microbial and plant food proteins. Effects of food processing and hydrolyzation conditions as well as some other impacts on formation, activity and stability of these hydrolyzates and peptides are also presented.
    Critical Reviews in Food Science and Nutrition 07/2014; DOI:10.1080/10408398.2012.724478
  • [Show abstract] [Hide abstract]
    ABSTRACT: This work is a literature overview on angiotensin-converting enzyme (ACE) inhibitory/antihypertensive peptides in food protein sources. The following aspects related to peptides with the above-mentioned bioactivity are discussed: (i) mechanism of action of ACE, (ii) the structural character of ACE inhibitors/antihypertensive peptide sequences determined by different methods, including quantitative structure–activity relationship studies, (iii) their food sources, (iv) absorption of peptides, (v) in vitro and in vivo approaches involved in the production and potential release of peptide ACE inhibitors as well as in silico methods applied in research concerning peptides.
    Comprehensive Reviews in Food Science and Food Safety 02/2014; 13(2):114-134. DOI:10.1111/1541-4337.12051