Haptoglobin (Hp) binds human hemoglobin (Hb), contributing to prevent extra-erythrocytic Hb-induced damage. Hp forms preferentially complexes with αβ dimers, displaying heme-based reactivity. Here, kinetics and thermodynamics of fluoride and azide binding to ferric human Hb (Hb(III)) complexed with the human Hp phenotypes 1-1 and 2-2 (Hp1-1:Hb(III) and Hp2-2:Hb(III), respectively) are reported (pH 7.0 and 20.0 °C). Fluoride binds to Hp1-1:Hb(III) and Hp2-2:Hb(III) with a one-step kinetic and equilibrium behavior. In contrast, kinetics of azide binding to and dissociation from Hp1-1:Hb(III)(-N) and Hp2-2:Hb(III)(-N) follow a two-step process. However, azide binding to Hp1-1:Hb(III) and Hp2-2:Hb(III) is characterized by a simple equilibrium, reflecting the compensation of kinetic parameters. The fast and the slow step of azide binding to Hp1-1:Hb(III) and Hp2-2:Hb(III) should reflect azide binding to the ferric β and α chains, respectively, as also proposed for the similar behavior observed in Hb(III). Present results highlight the ligand-dependent kinetic inequivalence of Hb subunits in the ferric form, reflecting structural differences between the two subunits in the interaction with some ferric ligands.
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http://dx.doi.org/10.1007/s00775-019-01642-9 | DOI Listing |
Bioorg Chem
February 2025
Department of Chemistry, Faculty of Science, Taibah University, Al-Madinah Al-Munawarah 30002 Saudi Arabia. Electronic address:
The discovery of novel anti-cancer drugs motivated us to synthesize a new series of triple 1,2,3-triazole-based arm scaffolds featuring distinct un functionalized alkyl and/or aryl side chains with possible anti-cancer action using the click chemistry approach under both conventional and green microwave irradiation (MWI) methods. The Cu(I) catalyzed cycloaddition reaction of targeted tris-alkyne with un functionalized aliphatic and aromatic azides has been adopted as an efficient approach for synthesizing the desired click adducts. Microwave irradiation improved the synthetic processes, resulting in higher yields and faster reaction times.
View Article and Find Full Text PDFPolymers (Basel)
December 2024
College of Architecture and Civil Engineering, Beijing University of Technology, Beijing 100124, China.
Filler defects and matrix crosslinking degree are the main factors affecting the interfacial adhesion properties of propellants. Improving adhesion can significantly enhance debonding resistance. In this study, all-atom molecular dynamics (MD) simulations are employed to investigate the interfacial adsorption behavior and mechanisms between ammonium perchlorate (AP) fillers and a poly(3,3-bis-azidomethyl oxetane)-tetrahydrofuran (PBT) matrix.
View Article and Find Full Text PDFBiosens Bioelectron
March 2025
National Research Council (CNR), Institute of Applied Sciences and Intelligent Systems, I-80131, Naples, Italy. Electronic address:
Spectrochemical analysis of trace elements in complex matrices is crucial across various fields of science, industry, and technology. However, this analysis is often hindered by background interference and the challenge of detecting ultralow analyte concentrations. Surface Enhanced Infrared Absorption (SEIRA) spectroscopy is emerging as a viable technique to address these challenges as it can successfully reveal soluble and unmodified analytes in a label-free manner through their interactions with a bioreceptor following site-specific labeling with small infrared-active probes.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
Department of Nuclear Medicine, The Third Affiliated Hospital of Sun Yat-sen University, 600 Tianhe Road, Guangzhou 510630, China.
Epstein-Barr nuclear antigen 1 (EBNA1), a sequence-specific DNA binding protein of Epstein-Barr virus (EBV), is essential for viral genome replication and maintenance and is therefore an attractive target for the therapeutic intervention of EBV-associated cancers. Several EBNA1-specific inhibitors have demonstrated the ability to block EBNA1 function in vitro, but practical delivery strategies for these inhibitors in vivo are still lacking. Here, we report an intelligent hierarchical targeting theranostic nanosystem (denoted as mZGOCS@MnO-P5) that integrates an azide (N3) terminal dual-targeting peptide (N3-P5), a tumor microenvironment-responsive degradable MnO nanosheet, and a mesoporous ZnGaO:Cr, Sn near-infrared persistent luminescence (NIR-PL) nanosphere (mZGOCS).
View Article and Find Full Text PDFAnal Chem
December 2024
Key Laboratory of Dairy Science, Ministry of Education, College of Food Science, Northeast Agricultural University, Harbin 150030, China.
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