In Figure 4, a screen capture of the PepMatch module of DeCyder MS is shown, covering the peptide LGMYPPNM representing the main olive allergen of these samples. The average ratio of this peptide between Ole_e1_"mer" and Ole_e1_"lite" was 3.8 times, as shown in the peptide table above the 2-D and 3-D signal intensity maps. This is also in agreement with the gel filtration data of the two allergen samples, which showed an average difference of 3.5 times after integration of the UV traces for the collected fractions.
LGMYPPNM was the only peptide that was identified in all Ole e 1 proteins identified in this study, resulting in a total quantitation of the allergens present in the two batches. This finding also reflects the fact that the most intense signals in DeCyder MS for all detected and matched Ole e 1 peptides were obtained for this peptide. From Figure 4 it can also be seen that signal intensities from singly as well as doubly charged forms of LGMYPPNM were used for calculation of the relative abundances of this specific peptide in the two batches of pollen. Also shown in the list above the 2-D and 3-D signal intensity maps are p values, identification details, molecular masses of the compared peptides, number of matched profiles, signal intensities of each matched peptide, etc.
Among other Ole e 1 peptides detected, some were found to be unique for different isoforms of the protein. In Figure 5, another view from PepMatch is shown, demonstrating a four-fold difference in abundance between Ole_e1_"mer" and Ole_e1_"lite" for the peptide DCDEIPIEGWAKPSLK. This peptide was found to be unique for the Ole e 1 protein, with a molecular mass of 16616 Da and accession number CAA73036.1. In total, five isoforms of Ole e 1 could