Caratterizzazione delle isoforme della “Agglutinina del Germe di Grano (WGA)" mediante analisi proteomica

The wheat germ agglutinin (WGA) is a lectin of approximately 18 kDa, predominantly expressed in the germinal tissue, involved in the plant's immune system and currently considered the only biomarker of wheat germ. Similar to other lectins, WGA is a globular protein that binds sugars and/or glyco-conjugates. These proteins are considered anti-nutritional elements as they affect the integrity of the intestinal epithelium. In vitro studies have also demonstrated that WGA possesses antifungal and antitumor properties, making it of interest for biomedical applications. A detailed analysis of WGA is of interest from both nutritional and technological perspectives, as this protein is a biomarker of whole-grain products. The aim of this study was to characterize WGA from durum wheat germ using proteomic analysis. The experimental approach involved the purification of WGA by affinity chromatography, using a glycoprotein-based resin, followed by characterization through gel-based (SDS-PAGE) and gel-free (HPLC and mass spectrometry) proteomics. LC-MS/MS analysis enabled the identification of two isoforms of WGA, named WGA1 and WGA3, and their respective proteotypic peptides, thus laying the foundations for both qualitative (technological) and quantitative (bioactivity/nutritional) analyses of WGA in germ and processed products.