PubMed · 14015857
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M P BROTT. 1963. Programming storage facilities.. https://pubmed.ncbi.nlm.nih.gov/14015857/
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The soybean Kunitz trypsin inhibitor (SKTI) is a 21.5 kDa allergenic protein that belongs to the family of all antiparallel beta-sheet proteins that are highly resistant to thermal and chemical denaturation. Spectroscopic and biochemical techniques such as circular dichroism (CD), ANS fluorescence and proteolysis were used to study its molecular structure under denaturing conditions such as acid and heat to which these allergens are commonly exposed during food processing. Reduction of native SKTI leads to its complete and rapid proteolysis by pepsin in simulated gastric fluid (SGF). Limited proteolysis with chymotrypsin during renaturation after heating showed that the native structure reforms at around 60 degrees C reversing the denaturation. CD spectra revealed that under acid denaturing conditions, SKTI shows major changes in conformation, indicating the possibility of a molten structure. The existence of this intermediate was established by ANS fluorescence studies at different concentrations of HCl. The remarkable stability of SKTI to both thermal and acid denaturation may be important for its role as a food allergen.
Enzymatic digestion of total protein along with liquid chromatography/tandem mass spectrometry (LC/MS/MS) was used to confirm the presence of a major peanut allergen in food. Several peptides obtained from the enzymatic digestion of the most abundant peanut allergen, Ara h 1, were identified as specific peptide biomarkers for peanut protein. Using ice cream as a model food matrix, a method was developed for the detection of the allergen peptide biomarkers. A key component of the method was the use of molecular mass cutoff filters to enrich the Ara h 1 in the protein extracts. By applying the method to ice cream samples containing various levels of peanut protein, levels as low as 10 mg/kg of Ara h 1 could routinely be detected. This method provides an unambiguous means of confirming the presence of the peanut allergen, Ara h 1, in foods and can easily be modified to detect other food allergens.
BACKGROUND: Eosinophils play an important role in the pathogenesis of allergic diseases. Sensitization and exposure to cockroach allergen have been demonstrated to be one of the major risk factors for the development of bronchial asthma. However, little is known regarding the functional capacity of cockroach extract antigen to activate human eosinophils. OBJECTIVE: We investigated whether German cockroach extract can activate human eosinophils to release cytotoxic inflammatory mediators. METHODS: Purified eosinophils from the peripheral blood were incubated with various concentrations (0-200 microg/ml) of German cockroach extract antigen. Effector functions of eosinophils were checked by degranulation and superoxide anion production. In addition, we examined surface expression of CD11b and CD69, and intracellular activation of p38 mitogen-activated protein kinase (p38 MAP kinase) in cockroach-stimulated eosinophils. RESULTS: German cockroach extract induced degranulation and superoxide production from human eosinophils. In addition, incubation of eosinophils for 3 h with the cockroach extract resulted in an increased level of the surface expression of CD11b and CD69. Furthermore, cockroach-induced superoxide production from eosinophils was significantly inhibited by the pretreatment of cells with a p38 MAP kinase inhibitor SB202190. Indeed, a large amount of phosphorylated forms of p38 MAP kinase was detected in cockroach-stimulated eosinophils. CONCLUSIONS: Our results suggest that German cockroach extract induces activation of human eosinophils to release cytotoxic inflammatory mediators such as superoxide and granular proteins.