Interaction of the Kunitz soybean trypsin inhibitor with bovine trypsin. Evidence for an acyl-enzyme intermediate during complexation

Biochemistry ◽  
1977 ◽  
Vol 16 (11) ◽  
pp. 2474-2478 ◽  
Author(s):  
Jung-San Huang ◽  
Irvin E. Liener
Keyword(s):  
Trypsin Inhibitor ◽  
Soybean Trypsin Inhibitor ◽  
Bovine Trypsin ◽  
Enzyme Intermediate

Purification and characterization of trypsin from the Greenland cod (Gadus ogac). 1. Kinetic and thermodynamic characteristics

1984 ◽  
Vol 62 (9) ◽  
pp. 894-900 ◽  
Author(s):  
B. K. Simpson ◽  
N. F. Haard
Keyword(s):  
Trypsin Inhibitor ◽  
Polyacrylamide Gel Electrophoresis ◽  
Thermodynamic Characteristics ◽  
Soybean Trypsin Inhibitor ◽  
Turnover Number ◽  
Bovine Trypsin ◽  
Hydrolytic Reaction ◽  
Entropy Of Activation ◽  
Sepharose 4B ◽  
Hydrolysis Of

Trypsinogen was isolated from the pyloric ceca of Greenland cod by ammonium sulfate fractionation followed by acetone precipitation, and the trypsin(ogen) thus obtained was purified by affinity chromatography on soybean trypsin inhibitor – Sepharose 4B. The purified trypsin migrated as a single zone during polyacrylamide gel electrophoresis and its identity as trypsin (EC 3,4.21.4) was established by its catalytic specificity for amide or ester bonds involving the carboxyl group of arginine, its sensitivity to serine protease inhibitors and soybean trypsin inhibitor, and its molecular weight of 23 500. With tosylarginine methyl ester (TAME) as substrate, the turnover number of the hydrolytic reaction was about three times greater for the cod trypsin than for bovine trypsin at 5 °C. The Michaelis–Menten constant (Km,app) for cod trypsin and TAME increased from 0.14 mM at 5 °C to 0.26 mM at 35 °C, while the Km,app for bovine trypsin – TAME was about 0.05 mM at all assay temperatures. The free energy of activation (ΔG*) for the hydrolysis of TAME was about 600 cal/mol (1 cal = 4.1868 J) lower for the cod trypsin than for bovine trypsin at 5 °C. The contribution of enthalpy of activation (ΔH*) and entropy of activation (ΔS*) to ΔG* differed considerably for the two enzymes. The "physiological efficiency" (Vmax/Km,app) of the two enzymes with TAME was similar at 5 °C, but was much greater for bovine trypsin than cod trypsin at warmer temperatures. With N-α-benzoylarginine-p-nitroanilide (BAPA) as substrate, the turnover number was about eight times greater for the cod trypsin at 25 °C. The Km,app for cod trypsin – BAPA increased from 1.67 mM at 25 °C to 1.84 mM at 35 °C, whereas the Km,app for bovine trypsin – BAPA decreased from 0.97 mM at 25 °C to 0.90 mM at 35 °C. The ΔG* for hydrolysis of BAPA was about 1800 cal/mol lower for cod trypsin than it was for bovine trypsin at 25 °C. Vmax/Km,app was three to four times greater for cod trypsin than for bovine trypsin at 25 and 35 °C. These results show that Greenland cod trypsin is a better catalyst than bovine trypsin at low temperatures and that catalysis by the fish trypsin is less responsive to temperature change than is catalysis by bovine trypsin.

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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