Properties Of Dipeptides Research Articles

Dipeptide Extract Modulates the Oxi-Antioxidant Response to Intense Physical Exercise.

Exposure to intense physical exercise increases reactive oxygen and nitrogen species production. The process can be modulated by dipeptide bioavailability with antioxidant scavenger properties. The effects of dipeptide intake in combination with physical exercise on the oxi-antioxidant response were examined in a randomized and placebo-controlled trial. Blood samples were collected from 20 males aged 21.2 ± 1.8 years before and after 14-day intake of chicken breast extract (4 g/day), which is a good source of bioactive dipeptides. A significant increase in the NO/H2O2 ratio was observed in the 1st and 30th minute after intense incremental exercise in dipeptides compared to the placebo group. Total antioxidant and thiol redox status were significantly higher in the dipeptide group both before and after exercise; η2 ≥ 0.64 showed a large effect of dipeptides on antioxidant and glutathione status. The level of 8-isoprostanes, markers of oxidative damage, did not change under the influence of dipeptides. By contrast, reduced C-reactive protein levels were found during the post-exercise period in the dipeptide group, which indicates the anti-inflammatory properties of dipeptides. High pre-exercise dipeptide intake enhances antioxidant status and thus reduces the oxi-inflammatory response to intense exercise. Therefore, the application of dipeptides seems to have favourable potential for modulating oxidative stress and inflammation in physically active individuals following a strenuous exercise schedule.

Self-Assembly Dipeptide Hydrogel: The Structures and Properties.

Self-assembly peptide-based hydrogels are well known and popular in biomedical applications due to the fact that they are readily controllable and have biocompatibility properties. A dipeptide is the shortest self-assembling motif of peptides. Due to its small size and simple synthesis method, dipeptide can provide a simple and easy-to-use method to study the mechanism of peptides’ self-assembly. This review describes the design and structures of self-assembly linear dipeptide hydrogels. The strategies for preparing the new generation of linear dipeptide hydrogels can be divided into three categories based on the modification site of dipeptide: 1) COOH-terminal and N-terminal modified dipeptide, 2) C-terminal modified dipeptide, and 3) uncapped dipeptide. With a deeper understanding of the relationship between the structures and properties of dipeptides, we believe that dipeptide hydrogels have great potential application in preparing minimal biocompatible materials.

Influence of C-terminal residues on the structural and molecular properties of dipeptides: a theoretical study in a vacuum and implicit and explicit aqueous environments

The role of C-terminal residues in influencing the structural and molecular properties of a set of six dipeptides was studied using the B3LYP/6-31++G(d,p) level of theory in a vacuum and implicit and explicit aqueous environment. The dipeptides were constructed by keeping pyrrolysine as a fixed component in the N-terminus whereas the component in the C-terminus was varied with six different combinations, viz. Val, Ile, Glu, Thr, Gln, and Lys. The C-terminal residues were chosen on the basis of the propensity of their side chain moieties to be in contact with a polar solvent like water. Frequency calculations on the fully optimized molecular geometries of the dipeptides confirmed them to be true minima. The HOMO/LUMO energies as well as their energy gaps, rotational constants, dipole moments, and theoretically predicted vibrational spectra of all the dipeptides were thoroughly analyzed. The identity of the varying C-terminal residue affects the value of the ϕ dihedral, planarity of the peptide plane, and geometry around the α-carbon atoms of a given dipeptide. Solvation effects of the implicit aqueous environment are found to modify the gas-phase conformation of a dipeptide around the angle ψ and influence the number and types of intramolecular H-bonds occurring in a dipeptide structure. The influence of the explicit aqueous environment is evident on the geometrical parameters associated with the geometries of amide planes and vibrational spectra of the dipeptides.

Structural and molecular properties of dipeptides containing N-terminal selenomethionine: a theoretical study

Although the genetic code encodes only 22 amino acids during protein bio-synthesis, there are more than 140 natural amino acids whose incorporation into the protein structures is vital for proper functioning of the chemical and bio-chemical machineries associated with living beings. Among these, selenium-containing amino acids are of special interest for amino acid biochemistry. During the last few decades, the structure–function relationships of proteins are being best pursued by considering amino acids, dipeptides as well as their analogs as model systems. By performing this theoretical study it is intended to investigate the influence of functional group/groups present in side chain moieties of the varying C-terminal residues on the molecular and structural features of a set of seven dipeptides, constructed by conserving selenomethionine at their N-terminal positions while the C-terminal ends are varied with one of the following amino acid residues—Val, Trp, Glu, Cys, Tyr, Arg, and Sec. Geometry optimization and vibrational frequency calculations were carried out in gas and aqueous phase using B3LYP/6-311++G(d,p) level of theory. The results furnished by this DFT study provide a good account of the role of the C-terminal residue’s identity in determining the structural features of the amide planes, values of the ψ and ф dihedrals, geometry about the α-carbon atoms, theoretical IR spectra and the number and type of intramolecular H-bond interactions existing in the dipeptides. In aqueous phase, the dipeptide geometries exhibit larger values of total dipole moments, greater HOMO–LUMO energy gaps and enhanced thermodynamic stability than those in gas phase.

Similarity of immunomodulating, phagocytosis-modulating, and antitoxic properties of dipeptides and their constituent amino acids

Immunomodulating, phagocytosis-modulating, and antitoxic properties of dipeptides depend on activities of their constituent amino acids. Some amino acids have considerable promise for efficient prevention of occupational diseases caused by chronic benzene intoxication.

Explanation for the non-specificity of small peptide-antibody interaction

Testing the reactivity of synthetic peptides with monoclonal antibodies provides information on protein-protein interactions. Starting from a minimal basis, that is considering dipeptide-antibody interactions, binding occurs in a reproducible manner. With no knowledge of the testing antibody specificity, peptide length is the only parameter which can be easily handled. Best binding dipeptides are then extended by adding one aminoacid to either end, and the process goes on with best binding tri, tetra, etc., -peptides. Such a process would be well founded if specificity was gained at each step. In fact, a computer analysis of experimental results shows that binding of dipeptide tends to be independent from the specificity of the antibody. An ad hoc method mainly based on ranking and sorting operations, assesses predominant factor(s) accounting for dipeptide reactivity. Moreover, properties of dipeptides are not generalisable to tripeptides. The continuity of the extension process cannot be assumed.

ChemInform Abstract: Syntheses and Properties of Dipeptides Containing γ‐Aminobutyric Acid or Its Analogues at the C‐Terminal.

ChemInform Abstract: Syntheses and Properties of Dipeptides Containing γ‐Aminobutyric Acid or Its Analogues at the C‐Terminal.

Syntheses and properties of dipeptides containing .GAMMA.-aminobutyric acid or its analogues at the C-terminal.

Syntheses and properties of dipeptides containing .GAMMA.-aminobutyric acid or its analogues at the C-terminal.