title: Quantification of genetically modified soya using strong anion exchange chromatography and time-of-flight mass spectrometry.
abstract: Stable-isotope dimethyl labeling was applied to the quantification of genetically modified (GM) soya. The herbicide-resistant gene-related protein 5-enolpyruvylshikimate-3-phosphate synthase (CP4 EPSPS) was labeled using a dimethyl labeling reagent, formaldehyde-H2 or -D2. The identification and quantification of CP4 EPSPS was performed using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). The CP4 EPSPS protein was separated from high abundance proteins using strong anion exchange chromatography and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Then, the tryptic peptides from the samples and reference were labeled with formaldehyde-H2 and formaldehyde-D2, respectively. The two labeled pools were mixed and analyzed using MALDI-MS. The data showed a good correlation between the peak ratio of the H- and D-labeled peptides and the GM soya percentages at 0.5, 1, 3, and 5 %, with R (2) of 0.99. The labeling reagents are readily available. The labeling experiments and the detection procedures are simple. The approach is useful for the quantification of GM soya at a level as low as 0.5 %.
authors: Department of Chemistry, National Dong Hwa University, Hualien, 97401, Taiwan, Republic of China.
authors: Po-Chih
authors: PC
authors: Chang
authors: P Muralidhar
authors: PM
authors: Reddy
authors: Yen-Peng
authors: YP
authors: Ho
mesh_terms: D051229:3-Phosphoshikimate 1-Carboxyvinyltransferase / Q000737:chemistry* / Q000235:genetics; D002852:Chromatography, Ion Exchange; D004591:Electrophoresis, Polyacrylamide Gel; D005506:Food Contamination / Q000032:analysis; D007553:Isotope Labeling; D013058:Mass Spectrometry; D010455:Peptides / Q000737:chemistry; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics; D030821:Plants, Genetically Modified / Q000737:chemistry*; D016133:Polymerase Chain Reaction; D040901:Proteomics; D015203:Reproducibility of Results; D013025:Glycine max / Q000737:chemistry* / Q000235:genetics; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014357:Trypsin / Q000737:chemistry
chemical_list: D010455:Peptides; D010940:Plant Proteins; D051229:3-Phosphoshikimate 1-Carboxyvinyltransferase; D014357:Trypsin