Peptide-bond hydrolysis equilibria in native proteins. Conversion of virgin into modified soybean trypsin inhibitor

Biochemistry ◽  
1969 ◽  
Vol 8 (1) ◽  
pp. 16-22 ◽  
Author(s):  
Carl W. Niekamp ◽  
Harry F. Hixson ◽  
Michael Laskowski
Keyword(s):  
Trypsin Inhibitor ◽  
Peptide Bond ◽  
Soybean Trypsin Inhibitor ◽  
Native Proteins

Factor X Activation by washed human platelets

1979 ◽  
Author(s):  
E van Wijk ◽  
L Kahlé ◽  
J ten Cate
Keyword(s):  
Human Factors ◽  
Trypsin Inhibitor ◽  
Calcium Ions ◽  
Factor Xa ◽  
Human Platelets ◽  
Soybean Trypsin Inhibitor ◽  
Thrombin Inhibitor ◽  
Chromogenic Substrate ◽  
Factor X ◽  
Factor X Activation

In a system of washed human platelets, Ca2+and purified human factors X anc II, a sufficient amount of thrombin is generated in about 10 minutes to aggregate the platelets. This thrombin is formed through the activation of FX by the platelets. In a system with either FX or FII present, no aggregation occurs. In addition no aggregation is observed when hirudin, a specific thrombin inhibitor, or when soybean trypsin inhibitor, which inhibits factor Xa, are added to the mixture. The formation of factor Xa can be monitored indirectly through the generation of thrombin, in the presence of an excess of prothrombin, using a thrombin sensitive chromogenic substrate. When washed platelets are incubated with FX alone for 10 minutes, no aggregation occurs and after the addition of prothrombin aggregation starts within 6 minutes. These findings confirm that washed platelets possess a factor X activating property. The generation of FXa proceeds in the absence of added Ca2+, whereas in the presence of Ca2+factor Xa activity reaches a maximum in 3 minutes, whereafter the activity progressively decreases. This may be due to the binding of Xa to the platelets in the presence of calcium ions.

DEVELOPMENT OF IMMUNOENZYME ANALYTICAL SYSTEMS FOR CONTROL OF THE CONTENT OF MAIN NON-MEAT COMPOUNDS IN PROCESSED MEAT PRODUCTS

2021 ◽  
Vol 1 (19) ◽  
pp. 322-324
Author(s):  
E.A. Zvereva ◽  
A.V. Zherdev ◽  
B.B. Dzantiev
Keyword(s):  
Connective Tissue ◽  
Enzyme Immunoassay ◽  
Trypsin Inhibitor ◽  
Meat Products ◽  
Soybean Trypsin Inhibitor ◽  
Processed Meat

Methods have been developed to control the content of non-meat components (connective tissue of animals, eggs, soy) in processed meat products, based on enzyme immunoassay of biomarker proteins – collagen, ovalbumin, soybean trypsin inhibitor.

Development of Enzyme-Linked Immunoassay Systems for Monitoring the Content of the Main Non-Meat Additives in Meat Products

2021 ◽  
Vol 37 (5) ◽  
pp. 117-122
Author(s):  
E.A. Zvereva ◽  
O.D. Hendrickson ◽  
B.B. Dzantiev ◽  
A.V. Zherdev
Keyword(s):  
Trypsin Inhibitor ◽  
Room Temperature ◽  
Meat Products ◽  
Reaction Medium ◽  
Soybean Trypsin Inhibitor ◽  
Russian Science ◽  
Additional Advantage ◽  
Relative Standard ◽  
Total Analysis ◽  
Kinetic Mode

Abstract-Methods for control of the content of non-meat components (connective tissue of animals, eggs, soybeans) in meat products have been developed based on competitive enzyme immunoassay of biomarker proteins: collagen, ovalbumin, and soybean trypsin inhibitor. Polyclonal rabbit antibodies against the biomarkers were produced. Screening of the following analysis conditions was carried out using the most affine preparations: the duration of the stages, the concentrations of the reagents, the composition of the reaction medium to ensure the completeness and the minimum limits of detection of analytes. It was shown that the immunochemical stage can be transferred to the kinetic mode and reduced to 20 min, while the total analysis took only 1 h. The selected conditions synchronized detection stages and provided the same signal amplitudes from all three biomarkers. An additional advantage of the method is that the analysis can be carried out at room temperature. The detection limits for collagen, ovalbumin and soybean trypsin inhibitor in the final extracts were 0.025 μg/mL, 0.012 μg/mL, and 0.001 μg/mL, respectively. Approbation of the method showed the reliability of the conclusions about the composition of the tested meat products; the relative standard deviation in the analysis of the monitored biomarkers was 8-10%. Key words: enzyme-linked immunoassay, meat products, collagen, ovalbumin, soybean trypsin inhibitor The work was financially supported by the Russian Science Foundation (project no. 19-16-00108).

scholarly journals Immunoreactivity of Lupine and Soybean Allergens in Foods as Affected by Thermal Processing

Foods ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 254 ◽  
Author(s):  
Caterina Villa ◽  
Mónica B. M. V. Moura ◽  
Joana Costa ◽  
Isabel Mafra
Keyword(s):  
Trypsin Inhibitor ◽  
Thermal Processing ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Meat Products ◽  
Soybean Trypsin Inhibitor ◽  
Thermal Treatments ◽  
Food Matrix ◽  
Soybean Proteins ◽  
Sds Page

Lupine and soybean are important technological aids for the food industry. However, they are also capable of inducing severe allergic reactions in food-sensitized/allergic individuals. In this context, this work intended to study the combined effects of thermal processing and food matrix on the immunoreactivity of lupine and soybean proteins used as ingredients in bakery and meat products, respectively. For this purpose, the effects of baking, mild oven cooking, and autoclaving on the protein profiles were evaluated, using model mixtures simulating the production of lupine-containing breads and soybean-containing cooked hams/sausages, by native- and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and immunoblotting using specific antibodies. The results showed that lupine gamma-conglutin immunoreactivity was slightly decreased in wheat flour mixtures compared to rice, but it was more pronounced in baked products. In meat mixtures, substantial protein fragmentation was noted after autoclaving, with decreased immunoreactivity of soybean trypsin inhibitor. The analysis of 22 commercial products enabled the identification of lupine gamma-conglutin in four bakery samples and soybean trypsin-inhibitor in five sausages, and further differentiated autoclaved from other milder thermally treated products. Generally, the immunoreactivity of target proteins was reduced by all the tested thermal treatments, though at a higher extent after autoclaving, being slightly altered by the food matrix.

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