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Characterization of Protein Fractions from Bt-Transgenic and Non-transgenic Maize Varieties Using Perfusion and Monolithic RP-HPLC. Maize Differentiation by Multivariate Analysis

Rodríguez-Nogales, J.M., Cifuentes, A., García, M.C., Marina, M.L.
Journal of agricultural and food chemistry 2007 v.55 no.10 pp. 3835-3842
insecticidal proteins, Zea mays, proteome, albumins, genetically modified foods, transgenic plants, prolamins, plant-incorporated protectants, corn, varieties, Bacillus thuringiensis, crystal proteins, reversed-phase high performance liquid chromatography, multivariate analysis, endotoxins, globulins
Protein fractions from transgenic Bt and non-transgenic maize varieties, extracted by the Osborne solvent fraction procedure, were characterized for the first time by perfusion and monolithic RP-HPLC in very short analysis times. Albumins and globulins from different transgenic Bt maizes as well as from their non-transgenic isogenic varieties were eluted in four peaks using perfusion RP-HPLC, whereas prolamins and glutelins were separated in seven peaks. Monolithic RP-HPLC enabled the separation of maize proteins in a large number of peaks showing 6 and 10 main peaks for albumins and globulins, respectively. Prolamins migrated at retention times higher than 5 min as seven peaks, whereas glutelins were separated in three main peaks appearing at retention times higher than 6.0 min. Moreover, chromatograms of the whole protein extracts showed 8 and 11 components for perfusion and monolithic RP-HPLC, respectively. A comparison of the chromatograms of the whole protein extracts relative to transgenic and non-transgenic varieties evidenced quantitative differences on the percentages of area, mainly for peaks 2 and 3 by perfusion RP-HPLC and for peaks 3 and 7 by monolithic RP-HPLC. A discriminant analysis based on these proteic profiles was carried out to classify and predict transgenic Bt maize lines, achieving 100% correct classification using perfusion RP-HPLC.