Absolute quantification of protein NP24 in tomato fruit by liquid chromatography/tandem mass spectrometry using stable isotope-labelled tryptic peptide standard

• Published in: Food chemistry Vol. 173; pp. 238 - 242
• Main Authors: Ippoushi, Katsunari, Sasanuma, Motoe, Oike, Hideaki, Kobori, Masuko, Maeda-Yamamoto, Mari
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 15.04.2015
• Subjects: Absolute quantification; Allergens - chemistry; Amino Acid Sequence; Chromatography, Liquid; Fruit - chemistry; Isotope Labeling; Liquid chromatography/tandem mass spectrometry; Lycopersicon esculentum - chemistry; Lycopersicon esculentum Mill; Molecular Sequence Data; Plant Proteins - chemistry; Protein NP24; Stable isotope-labelled peptide; Tandem Mass Spectrometry; Tomato; Trypsin; Stable isotope-labelled peptide; Trypsin; Protein NP24; Absolute quantification; Liquid chromatography/tandem mass spectrometry; Tomato; Lycopersicon esculentum Mill
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2014.10.008

•NP24 is a protein in tomato (Lycopersicon esculentum Mill.).•NP24 is reported to be a putative tomato allergen and listed as a food allergen.•A quantitative method to assay NP24 was developed using AQUA peptide and LC/MS/MS.•A linear relationship (r2>0.99) was observed over the range 2.0–500fmol/μL.•Coefficients of variation measured on each of 5day-assays for NP24 were <13%. Protein NP24 is a thaumatin-like protein contained in tomato (Lycopersicon esculentum Mill.). This protein is reported to be a putative tomato allergen and is listed as a food allergen in Structural Database of Allergenic Proteins (SDAP). In this research, we developed the quantitative analysis of NP24 by employing the protein absolute quantification (AQUA) technology composed of stable isotope-labelled internal standard (SIIS) peptide (GQTWVINAPR[13C6,15N4]) and liquid chromatography/tandem mass spectrometry (LC/MS/MS). A linear relationship (r2>0.99) was found throughout the concentration range (2.0–500fmol/μL). The coefficients of variation (CVs) measured on each of the five days when NP24 contained in the tomato skin was analysed did not exceed 13%. Our developed assay of NP24 will contribute to the allergological examination of tomato and its derived products.