Comparison of tropomyosin released peptide and epitope mapping after in vitro digestion from fish (Larimichthys crocea), shrimp (Litopenaeus vannamei) and clam (Ruditapes philippinarum) through SWATH-MS based proteomics.

• Digestion products of shrimp-TM yielded many peptides matched T/B cell epitopes. • Digestion products of shrimp-TM in SGF profile showed a significant difference from others. • Peptides of shrimp-TM matched more T/B cell epitopes than those of fish-TM and clam-TM. • Core regions of shrimp-TM matched T/B cell epitopes are distributed along the entire chain. • A differentiating peptide of shrimp-TM (72–88) could be as a potential peptide marker. Tropomyosin (TM) is a major shellfish allergen and a minor fish allergen. Different digestion profiles affect potential allergen anaphylaxis of protein. In this study, released peptides of fish-TM, shrimp-TM, and clam-TM by in vitro digestion of simulated gastric fluid (SGF), simulated intestinal fluid (SIF), and gastrointestinal (GI) were analyzed using sequential windowed acquisition of all theoretical fragment ion mass spectra (SWATH-MS) based proteomics. Results showed that digestion products of shrimp-TM yielded a lot of peptides matched T/B cell epitopes while core regions matched epitopes were distributed along the entire chain. Pepsin or trypsin-based digestion products of shrimp-TM presented many more peptides matched T/B cell epitopes compared with those of fish-TM and clam-TM. Besides, a differentiating peptide of VEKDKALSNAEGEVAAL (72–88) overlapped T/B cell epitopes could be used as a candidate peptide marker to identify tropomyosin allergen. These findings would supply new insight into the different allergenicity of tropomyosin. [ABSTRACT FROM AUTHOR]