TAILIEUCHUNG - Báo cáo khoa học: Stability of the major allergen Brazil nut 2S albumin (Ber e 1) to physiologically relevant in vitro gastrointestinal digestion

The major 2S albumin allergen from Brazil nuts, Ber e 1, was subjected to gastrointestinal digestion using a physiologically relevantin vitro model sys-tem either before or after heating (100 C for 20 min). Whilst the albumin was cleaved into peptides, these were held together in a much larger struc-ture even when digested by using a simulated phase 1 (gastric) followed by a phase 2 (duodenal) digestion system. Neither prior heating of Ber e 1 nor the presence of the physiological surfactant phosphatidylcholine affected the pattern of proteolysis. After 2 h of gastric digestion, 25% of the allergen remained intact, 50% corresponded to a large fragment ofMr 6400, and. | ềFEBS Journal Stability of the major allergen Brazil nut 2S albumin Ber e 1 to physiologically relevant in vitro gastrointestinal digestion F. Javier Moreno1 Fred A. Mellon1 Martin S. J. Wickham1 Andrew R. Bottrill2 and E. N. Clare Mills1 1 Institute of Food Research Norwich Research Park Norwich UK 2 John Innes Centre Norwich Research Park Norwich UK Keywords 2S albumin digestion food allergy mass spectrometry Brazil nut Correspondence F. J. Moreno Fundacion AZTI Txatxarramendi ugartea z g 48395 Sukarrieta Bizkaia Spain Fax 34 946870006 Tel 34 946029410 E-mail jmoreno@ Received 3 August 2004 revised 29 October 2004 accepted 5 November 2004 doi The major 2S albumin allergen from Brazil nuts Ber e 1 was subjected to gastrointestinal digestion using a physiologically relevant in vitro model system either before or after heating 100 C for 20 min . Whilst the albumin was cleaved into peptides these were held together in a much larger structure even when digested by using a simulated phase 1 gastric followed by a phase 2 duodenal digestion system. Neither prior heating of Ber e 1 nor the presence of the physiological surfactant phosphatidylcholine affected the pattern of proteolysis. After 2 h of gastric digestion w 25 of the allergen remained intact w 50 corresponded to a large fragment of Mr 6400 and the remainder comprised smaller peptides. During duodenal digestion residual intact 2S albumin disappeared quickly but a modified form of the large fragment remained even after 2 h of digestion with a mass of w 5000 Da. The large fragment comprised several smaller peptides that were identified by using different MS techniques as deriving from the large subunit. In particular sequences corresponding to the hypervariable region Q37-M47 and to another peptide P42-P69 spanning the main immunoglobulin E epitope region of 2S albumin allergens were found to be largely intact following phase 1 gastric digestion. They also contained .

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