Rapid simulated gastric fluid digestion of in-seed/grain proteins expressed in genetically engineered crops

• Published in: Regulatory toxicology and pharmacology 2016-11, Vol.81, p.106-112
• Main Authors: Schafer, Barry W., Embrey, Shawna K., Herman, Rod A.
• Format: Article
• Language: English
• Subjects: Allergenicity; Allergens - adverse effects; Allergens - genetics; Allergens - immunology; Allergens - metabolism; Crops, Agricultural - adverse effects; Crops, Agricultural - genetics; Crops, Agricultural - immunology; Crops, Agricultural - metabolism; Digestion; Food Hypersensitivity - etiology; Food Hypersensitivity - immunology; Food Safety; Food, Genetically Modified - adverse effects; Gastric Juice - chemistry; Gastric Juice - metabolism; Genetically engineered; Genetically modified; Humans; In-matrix; Plant Proteins - adverse effects; Plant Proteins - genetics; Plant Proteins - immunology; Plant Proteins - metabolism; Plants, Genetically Modified - adverse effects; Plants, Genetically Modified - genetics; Plants, Genetically Modified - immunology; Plants, Genetically Modified - metabolism; Proteolysis; Purified proteins; Risk Assessment; Seeds - adverse effects; Seeds - genetics; Seeds - immunology; Seeds - metabolism; Simulated gastric fluid; Time Factors; Transgenic
• ISSN: 0273-2300; 1096-0295
• DOI: 10.1016/j.yrtph.2016.08.004

The speed of simulated gastric digestion of proteins expressed in genetically engineered (GE) crops is commonly used to inform the allergenicity risk assessment. However, persistence of purified proteins in simulated gastric fluid (SGF) is poorly correlated with the allergenic status of proteins. It has been proposed that the plant or food matrix may affect the digestion of proteins and should be considered in interpreting digestion results. Here the SGF digestion of several GE proteins both as purified preparations and in soybean, corn, and cotton seed/grain extracts (in-matrix) are compared. Cry1F, Cry1Ac, phosphinothricin acetyltransferase (PAT), aryloxyalkanoate dioxygenase-1 (AAD-1), aryloxyalkanoate dioxygenase-12 (AAD-12), and double mutant 5-enol pyruvylshikimate-3-phosphate synthase (2mEPSPS) were all found to rapidly digest both as purified protein preparations and in seed/grain extracts from GE crops expressing these proteins. Based on these results, purified protein from microbial sources is a suitable surrogate for proteins in-matrix when conducting SGF digestion studies. •SGF digestion is used to inform the allergenicity assessment of GE proteins.•SGF digestion of pure proteins is poorly correlated with allergenic status.•In-matrix digestion has been hypothesized to better predict allergenic risk.•GE proteins in seed/grain extracts digest similarly to pure proteins in SGF.•Pure-protein SGF digestion is a good surrogate for in-matrix digestion.