The determination of trypsin inhibitor (TI) activity is of importance to evaluate the nutritional value of soybean flours. An analytical method, which involves a continuous spectrophotometric rate determination for trypsin activity against the substrate N-benzoyl-DL-arginine p-nitroanilide, is proposed as an alternative to the standard discontinuous assay. Stopping the reaction with acetic acid and a centrifugation/filtration step to decrease turbidity are not required, thus reducing costs and sample preparation time. The TI activity of different flour samples, determined by both assays, demonstrated to be statistically comparable, irrespective of the TI concentration level. The coefficients of variation of the novel method did not exceed 8% at any concentration level. The curves of progress reaction showed a non-linear behavior in samples without TI. A reduction of incubation time from 10min to 2min increased the method sensitivity and extended its linear range. A more economical, faster and simpler assay was developed.
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http://dx.doi.org/10.1016/j.foodchem.2016.07.056 | DOI Listing |
Int J Mol Sci
December 2024
Key Laboratory for Forest Genetics and Tree Improvement and Propagation in University of Yunnan Province, Southwest Forestry University, Kunming 650224, China.
Plant protease inhibitors are a ubiquitous feature of plant species and exert a substantial influence on plant stress responses. However, the (Kunitz trypsin inhibitor) family responding to abiotic stress has not been fully characterized in . In this study, we conducted a genome-wide study of the family and analyzed their gene structure, gene duplication, conserved motifs, cis-acting elements, and response to stress treatment.
View Article and Find Full Text PDFJ Biol Chem
January 2025
Department of Microbiology and Immunology, Nihon University School of Dentistry, Tokyo, Japan. Electronic address:
Influenza is a worldwide health problem that causes significant morbidity and mortality among the elderly; therefore, its prevention is important. During influenza virus infection, the cleavage of hemagglutinin (HA) is essential for the virus to enter host cells. Influenza virus-bacteria interactions influence the pathogenicity of infections, and specific bacteria contribute to the severity of the disease by participating in HA cleavage.
View Article and Find Full Text PDFNat Commun
January 2025
University/BHF Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK.
Corticosteroid binding globulin (CBG; SERPINA6) binds >85% of circulating glucocorticoids but its influence on their metabolic actions is unproven. Targeted proteolytic cleavage of CBG by neutrophil elastase (NE; ELANE) significantly reduces CBG binding affinity, potentially increasing 'free' glucocorticoid levels at sites of inflammation. NE is inhibited by alpha-1-antitrypsin (AAT; SERPINA1).
View Article and Find Full Text PDFJ Fluoresc
January 2025
School of Light Industry, Beijing Technology and Business University, Beijing, 100048, China.
A pyrene-derived fluorescent probe (P4CG) was designed and synthesized for the purpose of detecting protamine and trypsin activity. The anionic probe self-assembled with protamine, driven by electrostatic and hydrophobic interactions, exhibiting a sensing behavior towards protamine in a fluorescence ratiometric manner. The assay demonstrated high sensitivity, with a limit of detection (LOD) of 13.
View Article and Find Full Text PDFFertil Steril
January 2025
Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO 63104 USA. Electronic address:
Background: Thrombin prefers substrates carrying Arg at the site of cleavage (P1) because of the presence of D189 in the primary specificity (S1) pocket but can also cleave substrates carrying Phe at P1. The structural basis of this property is unknown.
Objective: Solve the X-ray structure of thrombin bound to a ligand carrying Phe at P1 and investigate the effects of replacing D189.
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