The synthesis of specifically deuterated uridine, its incorporation into an RNA oligonucleotide substrate, and the use of the labeled substrate to determine the deuterium kinetic isotope effect for the reaction catalyzed by the pseudouridine synthases (enzymes that isomerize uridine to pseudouridine in RNA) are described. Both enzymes-TruB and RluA-display a primary kinetic isotope effect, which indicates the formation of a glycal intermediate in the ribose ring during turnover. Although the details of the protocols are specific to these two enzymes, the general methodology is readily adaptable to the synthesis and incorporation of other labeled nucleosides into any RNA molecule by in vitro transcription.
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http://dx.doi.org/10.1016/bs.mie.2017.07.018 | DOI Listing |
Metabolism
March 2025
Department of Endocrinology, Copenhagen University Hospital Hvidovre, Denmark; Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark. Electronic address:
Background: Triacylglycerol (TAG) plasma excursions after a high-fat meal are blunted after Roux-en-Y gastric bypass (RYGB), but underlying mechanisms are poorly understood. We studied TAG absorption and metabolism in 12 RYGB-operated individuals and 12 unoperated controls (CON) matched on sex, age, and BMI.
Methods: Participants followed a 7-day controlled diet and on day 4 underwent H-MR Spectroscopy of liver TAG and a high-fat liquid meal with oral and intravenous labeled stable isotope metabolites, subcutaneous abdominal fat biopsies, and indirect calorimetry.
Int J Radiat Oncol Biol Phys
March 2025
Department of Physics, The University of Adelaide, Adelaide SA 5005, Australia; Allied Health & Human Performance, University of South Australia, Adelaide SA 5001, Australia.
Purpose: [Ac]Ac-DOTATATE is a promising treatment option for patients with neuroendocrine tumors. A concern with Ac is that the decay energy can break the bond to the targeting vehicle, producing free daughter radionuclides in the body. Daughter migration is generally not considered in clinical dosimetry, and therefore its effect needs to be studied.
View Article and Find Full Text PDFEnviron Sci Technol
March 2025
GEUS, Geological Survey of Denmark and Greenland, DK-1350 Copenhagen, Denmark.
The catalytic effect of aqueous Fe(II) (Fe) on the transformation of Fe(oxyhydr)oxides has been extensively studied in the laboratory. It involves the transfer of electrons between Fe and Fe-(oxyhydr)oxides, rapid atomic exchange of Fe between the two states, and recrystallization of the Fe-oxides into more stable Fe-(oxyhydr)oxides. The potential occurrence of these reactions in natural soils and sediments can have an important impact on biogeochemical cycling of iron, carbon, and phosphorus.
View Article and Find Full Text PDFBioorg Chem
March 2025
Department of Chemistry, University at Buffalo, Buffalo, New York 14260-3000, United States. Electronic address:
The small magnitudes of some kinetic isotope effects (KIEs), including those associated with C, necessitate a highly precise experimental approach involving the competition of light and heavy substrates. Provided the reaction is first order in the labeled substrate, the product isotopologue ratio converges to the initial reactant isotopologue ratio at completion, but the same is not true for dimerization reactions simply because the product diverges into four distinct isotopologues. The relative populations of these dimers deviate from the statistical distribution under the influence of a KIE.
View Article and Find Full Text PDFBreast Cancer Res
March 2025
Department of Breast and Endocrine Surgery, Osaka University Graduate School of Medicine, 2-2-E10 Yamada-oka, Suita, Osaka, 565-0871, Japan.
Background: Despite advances in breast cancer imaging, reliable detection of sentinel lymph node (SLN) metastasis remains challenging. This study aimed to determine the ability of immuno-positron emission tomography (PET) using Cu-labeled cetuximab to detect SLN metastasis in a model of epidermal growth factor receptor (EGFR)-positive breast cancer.
Methods: The SLN metastasis model was established using the EGFR-strongly-expressing MDA-MB-468 breast cancer cell line.
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