Evaluation of different types of milk proteins-derived epitopes using in-silico tools: a primarily study to propose a new definition for bioactive peptides

Abstract

Bioactive peptides are digestion-resistant and absorbable peptides released from dietary parent proteins. Dietary epitopes exert their effects on the body without absorption and release from parent protein. In this study, the epitope content of milk proteins was discovered, and a new definition for BPs is provided alongside the classic definition. In this study, LBtope, ABCpred, and SVMTriP servers were used to find Linear B cell epitopes. Besides, to predict T cell epitopes, the major histocompatibility complex I (MHC-I) and MHC-II alleles that were more abundant among Iranian people were first found from the Allele Frequency Net Database (AFND). Consequently, the IEDB, RANKPEP, SYFPEITHI, EpiJen, and EpiTOP3 servers were used for MHC binding epitopes. In the current study, MHC-II, MHC-I, and B-cell epitopes of milk proteins were discovered. The most important B-cell epitopes discovered by LBtope, ABCpred, and SVMtrip databases for αS1-casein included APSFSDIPNPIGSEN (176190), AESISSSEEIVPNSVE (62-77), and VFGKEKVNELSKDIGS (31-46). The high rank of αS1-casein derived from MHC-II epitopes and discovered from the SYFPEITHI database included KEKVNELSKDIGSES (34-48), RFFVAPFPEVFGKEK (22-36), and PELFRQFYQLDAYPS (147-161). The epitopes of dietary proteins and endogenous proteins could be considered as BPs. Epitopes exert their biological effects without absorption and release from parent proteins.