# Identification of Allergenic Tropomyosins with Known and Unknown Sequences in Seafood Products
## 3 Results
(**a**) Number of proteins containing a given peptide; (**b**) number of InterPro families containing a given peptide; (**c**) percentage of tropomyosins among proteins containing a given peptide; (**d**) percentage of proteins of organisms belonging to various taxa among the ones containing a given peptide. Heatmaps generated using HeatMapper program. Raw data are annotated in Table S8 in the Supplementary Materials. Meaning of font colors is the same as in Figure 2:1  
The number of proteins containing individual fragments is provided in Figure 6a. It varied from 10 to over 1000. Figure 6b shows the number of families including proteins with a given peptide. Families are defined according to the presence of specific domains [68; 69] understood as conserved parts of a sequence and a tertiary structure, attributed to protein function [70]. The same protein may contain more than one domain and thus belong to more than one family. Some peptides detected in the fried samples and not predicted belong to many families. The percentage of tropomyosins among the proteins containing particular fragments is displayed in Figure 6c. Most of the peptides occurred in protein sets  
Figure 2:2 Taxonomic lineage trees of peptides: (**a**) LAEASAQAADESERMR as an example of peptide characteristic for _Crustacac_; (**b**) IQLEEDLER as an example of peptide characteristic for _Arthropoda_; (**c**) IVELEEELKVVGNNMK as an example of peptide characteristic for _Mollusca_; (**d**) LSNQRQR as an example of peptide with inconclusive taxonomic lineage. Trees were generated using the Unipept program. containing 100 or nearly 100% of tropomyosins. There was also a relatively high number of proteins with undefined family. Among the unpredicted peptides, there were compounds derived from proteins belonging to various families. Peptides detected in the samples may be attributed to four categories: markers of crustaceans (yellow bands in the first, i.e., left column in Figure 6d), markers of arthropods (yellow bands in the second column from the left), markers of mollusks (yellow bands in third column) and inconclusive (yellow or green bands in two right columns-fourth and fifth). Taxonomic lineage trees of exemplary peptides representing the above categories are shown in Figure 2:3 Predicted peptides or their supersequences occur in tropomyosins of crustaceans, other arthropods (mainly _Hexupoda_ subphylum, especially insects) or mollusks. This finding is consistent with results of our previous concerning the distribution of epitopes from tropomyosin of Farfantepenaueus aztecus crustacean [12]. Peptides with taxonomic lineages belonging to the first three categories were found in the samples which were boiled or not subjected to thermal treatment. Peptides characteristic for Arthropoda may serve as markers of tropomyosins of not only of crustaceans but also of insects. Insects are recently considered as an emerging food source [71; 72; 73]. Their tropomyosins reveal cross-reactivity with those of the crustaceans [71]. Distribution of particular categories of peptide taxonomic lineages displayed in Figures 6 and 7 is summarized in Figure 2:4