Successive macroscopic pKa values have been determined potentiometrically for the conjugate acids of spermidine (4-azaoctane-1,8-diamine), spermine (4,9-diazadodecane-1,12-diamine) and some acylic diamines at various ionic strengths in the absence and presence of tetrasodium pyrophosphate. The stability of the amine/pyrophosphate adducts have been estimated on the basis of effects of the pyrophosphate ion on the apparent acidity constants of the amines. Stoichiometry and thermodynamics of adduct formation have been elucidated from microcalorimetric measurements.
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http://dx.doi.org/10.3891/acta.chem.scand.45-1055 | DOI Listing |
Nat Commun
January 2025
Center for Life Sciences, Yunnan Key Laboratory of Cell Metabolism and Diseases, State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, School of Life Sciences, Yunnan University, Kunming, China.
Phosphorus in crucial for all living organisms. In vertebrate, cellular phosphate homeostasis is partly controlled by XPR1, a poorly characterized inositol pyrophosphate-dependent phosphate exporter. Here, we report the cryo-EM structure of human XPR1, which forms a loose dimer with 10 transmembrane helices (TM) in each protomer.
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January 2025
School of Materials Science and Engineering, Jiangsu University of Science and Technology, Zhenjiang 212100, Jiangsu, China.
Three new sodium manganese fluoro-pyrophosphate compounds, namely, NaMn(PO)F (I), NaMn(PO)F (II), and NaMn(PO)F (III), have been synthesized by heating a mixture of NaPF, NaPOF or NaHPO with different Mn sources in NaNO and KNO fluxes. The structures of the title compounds were characterized single-crystal X-ray diffraction (XRD). II is characteristic of a shell of Na ions that encloses one [Mn(PO)F] unit, whereas I and III reveal three-dimensional (3D) frameworks that consist of MnO, Mn/NaOF octahedra or MnO octahedra and distorted MnO square pyramids with PO units, where Na cations reside in different-membered ring one-dimensional (1D) tunnels.
View Article and Find Full Text PDFMethods Mol Biol
January 2025
Department of Molecular and Cellular Biology, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan.
Functionally derivatized analogs of prenyl lipids are valuable tools for the detection and analysis of prenylated proteins. Using a biotinylated analog of geranylgeranyl, we previously identified Ykt6 as a substrate for a novel protein prenyltransferase, termed geranylgeranyltransferase type III (GGTase-III). Ykt6 is an evolutionarily highly conserved SNARE protein that regulates multiple intracellular trafficking pathways, including intra-Golgi trafficking and autophagosome-lysosome fusion.
View Article and Find Full Text PDFInt J Mol Sci
December 2024
Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan.
Phosphate invert glasses (PIGs) have been attracting attention as materials for bone repair. PIGs have a high flexibility in chemical composition because they are composed of orthophosphate and pyrophosphate and can easily incorporate various ions in their glass networks. In our previous work, incorporation of niobium (Nb) into melt-quench-derived PIGs was effective in terms of controlling their ion release, and Nb ions promoted the activity of osteoblast-like cells.
View Article and Find Full Text PDFInt J Mol Sci
December 2024
Clinic of Nuclear Medicine Central University Emergency Military Hospital "Dr Carol Davila", 10825 Bucharest, Romania.
Amyloidosis is a rare pathology characterized by protein deposits in various organs and tissues. Cardiac amyloidosis (CA) can be caused by various protein deposits, but transthyretin amyloidosis (ATTR) and immunoglobulin light chain (AL) are the most frequent pathologies. Protein misfolding can be induced by several factors such as oxidative stress, genetic mutations, aging, chronic inflammation, and neoplastic disorders.
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