High-intensity focused ultrasound (HIFU) is a noninvasive soft tissue ablation technique, which utilizes ultrasound energy to induce thermal coagulation necrosis in targeted tissues. Whether this high energy causes side effects in vivo, such as the formation of peptide bonds, has not been fully investigated. Glycylglycine is the simplest dipeptide and hence is often used as a model compound for peptide studies. In this study, we developed and validated a sensitive quantification method based on ion-exchange solid-phase extraction, liquid chromatography, and tandem mass spectrometry (SPE-LC-MS/MS) for the analysis of glycylglycine without derivatization, and then used it to evaluate whether HIFU promoted peptide bond formation in aqueous solution (without enzymes) and plasma (with enzymes). The results showed that strong cation exchange SPE significantly reduced the matrix effect and improved the sensitivity of the LC-MS/MS method. No formation of glycylglycine in the aqueous solution or plasma was observed following HIFU irradiation.
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http://dx.doi.org/10.1002/bmc.6067 | DOI Listing |
Alzheimers Dement
December 2024
Tsinghua university, Beijing, Beijing, China.
Background: Successive cleavages of amyloid precursor protein C-terminal 99 residues (APP-C99) by human γ-secretase result in amyloid-β peptides (Aβs) of varying lengths, the main constituents of amyloid plaques in Alzheimer's disease patients. Most cleavages have a step size of three residues, as exemplified by sequential generation of Aβ49, Aβ46, Aβ43, and Aβ40.
Method: To elucidate the mechanism of substrate cleavage, we determined atomic structures of human γ-secretase bound individually to APP-C99, Aβ49, Aβ46, and Aβ43.
Biomed Chromatogr
February 2025
College of Pharmacy, Chongqing Medical University, Chongqing, China.
High-intensity focused ultrasound (HIFU) is a noninvasive soft tissue ablation technique, which utilizes ultrasound energy to induce thermal coagulation necrosis in targeted tissues. Whether this high energy causes side effects in vivo, such as the formation of peptide bonds, has not been fully investigated. Glycylglycine is the simplest dipeptide and hence is often used as a model compound for peptide studies.
View Article and Find Full Text PDFSci Rep
January 2025
Department of Nanotechnology, Agricultural Biotechnology Research Institute of Iran (ABRII), Agricultural Research Education and Extension Organization (AREEO), P. O. Box: 31535-1897, Karaj, Iran.
Herein, an efficient and feasible approach was developed to oxidize low-cost agricultural waste (quinoa husk, QS) for the synthesis of carboxylated nanocellulose (CNC). The as-prepared rod-like CNCs (average diameter of 10 nm and length of 103 nm) with a high specific surface area (173 m/g) were utilized for the immobilization of a model protease enzyme (PersiProtease1) either physically or via covalent attachment. For chemical immobilization, CNCs were firstly functionalized with N, N'-dicyclohexylcarbodiimide (DCC) to provide DCNCs nanocarrier which could covalently bond to enzyme trough nucleophilic substitution reaction and formation of the amide bond between DCNCs and enzyme.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Laboratoire de Chimie Supramoléculaire, Institut de Science et d'Ingénierie Supramoléculaires (ISIS), Université de Strasbourg, Strasbourg 67000, France.
SAr reactions were remarkably accelerated using a pretargeting and activating unit based on dynamic covalent chemistry (DCvC). A Cys attack at the C-F bond on the aromatic ring of salicylaldehyde derivatives was only observed upon iminium formation with a neighboring Lys residue of model small peptides. Such self-activation was ascribed to the stronger electron-withdrawing capability of the iminium bond with respect to that of the parent aldehyde that stabilized the transition state of the reaction, together with the higher preorganization of the reactive groups in the cationic aldiminium species.
View Article and Find Full Text PDFImmunol Rev
December 2024
Laboratory of Immunobiology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA.
αβT cells protect vertebrates against many diseases, optimizing surveillance using mechanical force to distinguish between pathophysiologic cellular alterations and normal self-constituents. The multi-subunit αβT-cell receptor (TCR) operates outside of thermal equilibrium, harvesting energy via physical forces generated by T-cell motility and actin-myosin machinery. When a peptide-bound major histocompatibility complex molecule (pMHC) on an antigen presenting cell is ligated, the αβTCR on the T cell leverages force to form a catch bond, prolonging bond lifetime, and enhancing antigen discrimination.
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