BACKGROUND: By resisting digestion in the stomach, the major bovine milk allergen, beta-lactoglobulin, is believed to act as a transporter of vitamin A and retinol to the intestines. beta-Lactoglobulin has 2 intramolecular disulfide bonds that may be responsible for its allergic effects. OBJECTIVE: This study was carried out to assess the importance of disulfide bonds to the allergenicity and digestibility of beta-lactoglobulin. METHODS: beta-Lactoglobulin was subjected to reduction by the ubiquitous protein thioredoxin, which was itself reduced by the reduced form of nicotinamide adenine dinucleotide phosphate by means of nicotinamide adenine dinucleotide phosphate-thioredoxin reductase. Digestibility was measured with a simulated gastric fluid; results were analyzed by SDS-PAGE. Allergenicity was assessed with an inbred colony of high IgE-producing dogs sensitized to milk. RESULTS: As found for other proteins with intramolecular disulfide bonds, beta-lactoglobulin was reduced specifically by the thioredoxin system. After reduction of one or both of its disulfide bonds, beta-lactoglobulin became strikingly sensitive to pepsin and lost allergenicity as determined by skin test responses and gastrointestinal symptoms in the dog model. CONCLUSION: The results provide new evidence that thioredoxin can be applied to enhance digestibility and lower allergenicity of food proteins.
BACKGROUND: By resisting digestion in the stomach, the major bovinemilk allergen, beta-lactoglobulin, is believed to act as a transporter of vitamin A and retinol to the intestines. beta-Lactoglobulin has 2 intramolecular disulfide bonds that may be responsible for its allergic effects. OBJECTIVE: This study was carried out to assess the importance of disulfide bonds to the allergenicity and digestibility of beta-lactoglobulin. METHODS:beta-Lactoglobulin was subjected to reduction by the ubiquitous protein thioredoxin, which was itself reduced by the reduced form of nicotinamide adenine dinucleotide phosphate by means of nicotinamide adenine dinucleotide phosphate-thioredoxin reductase. Digestibility was measured with a simulated gastric fluid; results were analyzed by SDS-PAGE. Allergenicity was assessed with an inbred colony of high IgE-producing dogs sensitized to milk. RESULTS: As found for other proteins with intramolecular disulfide bonds, beta-lactoglobulin was reduced specifically by the thioredoxin system. After reduction of one or both of its disulfide bonds, beta-lactoglobulin became strikingly sensitive to pepsin and lost allergenicity as determined by skin test responses and gastrointestinal symptoms in the dog model. CONCLUSION: The results provide new evidence that thioredoxin can be applied to enhance digestibility and lower allergenicity of food proteins.
Authors: K V Soman; T Midoro-Horiuti; J C Ferreon; R M Goldblum; E G Brooks; A Kurosky; W Braun; C H Schein Journal: Biophys J Date: 2000-09 Impact factor: 4.033
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Authors: Ian Kimber; Rebecca J Dearman; Andre H Penninks; Leon M J Knippels; Robert B Buchanan; Bruce Hammerberg; Hilary A Jackson; Ricki M Helm Journal: Environ Health Perspect Date: 2003-06 Impact factor: 9.031
Authors: Elisabeth Hoflehner; Marina Binder; Wolfgang Hemmer; Vera Mahler; Raphael C Panzani; Reinhart Jarisch; Ursula Wiedermann; Michael Duchêne Journal: PLoS One Date: 2012-07-26 Impact factor: 3.240