A Novel Approach for Quantifying Allergenic Lipid Transfer Proteins, in Maize Kernels by LC-UV/MS

摘要

Maize (Zea mays) is not considered a major allergenic food; however, when food-induced allergenic and immunologic reactions have been associated with maize, lipid transfer proteins (LTPs) have been identified as the major allergens. LTP is an extremely stable protein that is resistant to both proteolytic attack and food processing, which permits the allergen to reach the gastrointestinal immune system in an immunogenic and allergenic conformation, allowing sensitization and induction of systemic symptoms. Because of different variants and isoforms owing to molecular heterogeneity and stability issues, a liquid chromatography with ultraviolet and mass spectrometric detection (LC-UV/MS) method was developed for LTP quantitation. The intact protein method allowed minimal sample handling, automated analysis, and relatively short analysis cycles for rapid data collection. The method allows for the differentiation between LTP and its variants, enabling the quantification of three different forms of LTP. The present assay enables determination of LTP over a concentration range from 29 to 1030 (mu)g/g in maize kernel samples. Assay recovery ((percent)RE) was measured at 11 different concentrations ranging from 4 to 147 (mu)g/mL and did not exceed 5.1percent. The precision ((percent)CV) was measured at 3 concentrations on each of 4 days and did not exceed 14.4percent. The assay was successfully used to determine and compare the levels of LTP in various maize lines and was sufficient to measure concentrations at physiologically relevant levels.