The BIOPEP-UWM™ database of bioactive peptides (formerly BIOPEP) has recently become a popular tool in the research on bioactive peptides, especially on these derived from foods and being constituents of diets that prevent development of chronic diseases. The database is continuously updated and modified. The addition of new peptides and the introduction of new information about the existing ones (e.g., chemical codes and references to other databases) is in progress. New opportunities include the possibility of annotating peptides containing D-enantiomers of amino acids, batch processing option, converting amino acid sequences into SMILES code, new quantitative parameters characterizing the presence of bioactive fragments in protein sequences, and finding proteinases that release particular peptides.

This review presents the potential for application of computational tools in peptide science based on a sample BIOPEP database and program as well as other programs and databases available via the World Wide Web. The BIOPEP application contains a database of biologically active peptide sequences and a program enabling construction of profiles of the potential biological activity of protein fragments, calculation of quantitative descriptors as measures of the value of proteins as potential precursors of bioactive peptides, and prediction of bonds susceptible to hydrolysis by endopeptidases in a protein chain. Other bioactive and allergenic peptide sequence databases are also presented. Programs enabling the construction of binary and multiple alignments between peptide sequences, the construction of sequence motifs attributed to a given type of bioactivity, searching for potential precursors of bioactive peptides, and the prediction of sites susceptible to proteolytic cleavage in protein chains are available via the Internet as are other approaches concerning secondary structure prediction and calculation of physicochemical features based on amino acid sequence. Programs for prediction of allergenic and toxic properties have also been developed. This review explores the possibilities of cooperation between various programs.

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.

No abstract

No abstract

The objectives of the present study were two-fold: first, to detect whether salmon protein fractions possess angiotensin I-converting enzyme (ACE) inhibitory properties and whether salmon proteins can release ACE inhibitory peptides during a sequential in vitro hydrolysis (with commercial porcine enzymes) and ex vivo digestion (with human gastrointestinal enzymes). Secondly, to evaluate the ACE inhibitory activity of generated hydrolysates. A two-step ex vivo and in vitro model digestion was performed to simulate the human digestion process. Salmon proteins were degraded more efficiently by porcine enzymes than by human gastrointestinal juices and sarcoplasmic proteins were digested/hydrolyzed more easily than myofibrillar proteins. The ex vivo digested myofibrillar and sarcoplasmic duodenal samples showed IC50 values (concentration required to decrease the ACE activity by 50%) of 1.06 and 2.16 mg/mL, respectively. The in vitro hydrolyzed myofibrillar and sarcoplasmic samples showed IC50 values of 0.91 and 1.04 mg/mL, respectively. Based on the results of in silico studies, it was possible to identify 9 peptides of the ex vivo hydrolysates and 7 peptides of the in vitro hydrolysates of salmon proteins of 11 selected peptides. In both types of salmon hydrolysates, ACE-inhibitory peptides IW, IY, TVY and VW were identified. In the in vitro salmon protein hydrolysates an ACE-inhibitory peptides VPW and VY were also detected, while ACE-inhibitory peptides ALPHA, IVY and IWHHT were identified in the hydrolysates generated with ex vivo digestion. In our studies, we documented ACE inhibitory in vitro effects of salmon protein hydrolysates obtained by human and as well as porcine gastrointestinal enzymes.

Multiple linear regression (MLR) models were constructed to explain the bitter taste of di-and tripeptides based on their chemical nature (structure). Sequences (51 di-and 51 tripeptides) were derived from the BIOPEP-UWM database of sensory peptides and amino acids. The measure of their bitterness was R caf. , that is, bitterness relative to that of 1 mM caffeine solution (R caf. 5 1.0).The variables were the indices describing properties of a single residue forming a peptide structure taken from ProtScale and Biological Magnetic Resonance Data Bank. MLR was made for two separate data sets by use of Statistica 13.1.We found that the presence of branched side residues or ring in a di-or tripeptide sequence (as in L, I, V, Y, F) affected its bitterness. Another variable affecting the bitter taste of di-and tripeptides was the hydrophobicity of amino acids. Using the commonly available statistical tools as well as chemical information reflecting the nature of peptides may be helpful in understanding the structure-taste relationship in food peptides. Practical applicationsOur approach takes account of bioinformatic and cheminformatic techniques of data mining to analyze structure-bitterness of di-and tripeptides derived from food protein sources. Data on bitter peptides available in databases of biological and chemical information can be useful in creating models which help understanding the relationship between the role of structural properties of a molecule (e.g., peptide) and its function (e.g., taste). The bitterness of a peptide resulting from the presence of specific residues in its sequence, which represent different physicochemical properties may contribute to extending the knowledge about their taste-forming role in food systems. Such knowledge may be useful in designing food products with improved properties like taste which can be either enhanced or masked (considered as unwanted when thinking about the sensory value of foods). Our research strategy is universal and can also be applied to study structurefunction relationships of peptides with other activities.

No abstract