Quantitative Structure-Activity Relationship Study of Radical Scavenging Peptides Based on Orac Method by Using Different Sets of Amino Acids Descriptor

Abstract

Some radical scavenging peptides by ORAC method from different hydrolysates were used for the quantitative structure-activity relationships (QSAR) research. Partial least-squares regression analysis (PLSR) was treated as the method to build the model with 17 kinds of amino acid descriptors. In order to translate the sequence to the same length, two-terminal position numbering (TTPN) was applied. Two of amino acid descriptors VSHE and VSW were selected for their excellent performance (R2, Q2, and RMSEcwith VHSE and VSW descriptor are 0.995, 0.630, 0.318 and 0.966, 0.543, 0.181 respectively). VHSE has the definite physicochemical meanings and easy to understand while VSW has good predictive ability (Rand RMSEpwith VHSE and VSW are 0.404, 2.633 and 0.635, 2.298 respectively). It is believed that the position No.2 amino acid from N-terminal (N2) have more importance than others in sequence, and most of electronic properties are negative to activity while all the steric properties are positive to activity as well as the hydrophobic properties. The suitable amino acids in sequence are as follow: G, R, K, W, Y, N, E, H, and Q are suitable for N2position which illustrated the importance of acidic amino acids in peptide sequence for radical scavenging activity.

Analysis of α‐helix unfolding in the pine nut peptide Lys‐Cys‐His‐Lys‐Pro induced by pulsed electric field

“…Therefore, the antioxidant activity of KCHKP, which is composed of the amino acids Lys, Cys, His and Pro, should be considered. Furthermore, the radical‐scavenging activity of antioxidant peptides is closely related to their ability for electronic and hydrogen bonding . On the basis of the results of the above series of experiments, evaluation of changes in the antioxidant activity of KCHKP induced by PEF is essential.…”

“…Furthermore, the radical-scavenging activity of antioxidant peptides is closely related to their ability for electronic and hydrogen bonding. 6,7 On the basis of the results of the above series of experiments, evaluation of changes in the antioxidant activity of KCHKP induced by PEF is essential. The DPPH radical-scavenging activity of KCHKP was slightly increased from 56.31% ± 0.74% to 84.33% ± 1.23%, and the ABTS radical-scavenging activity was significantly increased from 40.56% ± 0.78% to 51.33% ± 0.27% (P < 0.05), when the relative -helix content changed from 100% to 89.91% ± 0.97% under optimal PEF conditions ( Fig.…”

“…Various small peptides having different amino acid sequences are acquired from food‐derived proteins, allowing for more detailed investigations of their conformation and biological activity. For example, the spatial conformation, hydrophobicity, charge and hydrogen bonding of 214 types of tripeptides were studied using DPPS descriptors . Additionally, the secondary structures and biological activities of three novel inhibitory peptides of angiotensin converting enzyme, bearing the sequences RVPSL, QIGLF and TNGIIR, were analyzed by Fourier transform infrared (FTIR) spectroscopy for the first time .…”

“…For example, the spatial conformation, hydrophobicity, charge and hydrogen bonding of 214 types of tripeptides were studied using DPPS descriptors. 6,7 Additionally, the secondary structures and biological activities of three novel inhibitory peptides of angiotensin converting enzyme, bearing the sequences RVPSL, QIGLF and TNGIIR, were analyzed by Fourier transform infrared (FTIR) spectroscopy for the first time. 8 Tamburro et al studied the conformations of some polypeptides encoded by the human tropoelastin gene in different solvents and at different temperatures by circular dichroism (CD) and nuclear magnetic resonance (NMR), and found that the stability of the secondary structures was strongly dependent on the microenvironment.…”