Glutathione reductase (E.C.1.8.1.7) was purified from Phaeodactylum tricornutum cells grown axenically in an autotrophic medium. The overall procedure started with preparation of the cell extract and addition of ammonium sulfate to 20% saturation, followed by anion exchange and affinity interaction chromatography (Blue-A- and 2',5'-ADP-Sepharose). Complete purification required native polyacrylamide gel electrophoresis as the final step. The enzyme was purified to homogeneity and functionally characterized. Its native molecular mass was estimated to be 118 kDa; which corresponds to a dimer. The enzyme exhibited a specific activity of 190 U mg(-1) with an optimal activity at pH 8.0 and 32 degrees C. We determined K(m) values of 14 microM and 60 microM for NADPH and oxidized glutathione, respectively. Products inhibited the enzyme according to a hybrid ping-pong reaction mechanism. After MALDI-TOF analysis, the purified enzyme was unambiguously identified as one of the two proteins annotated as glutathione reductases in the genome of the diatom. The properties of the enzyme help to understand redox metabolic scenarios in P. tricornutum.
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http://dx.doi.org/10.1016/j.protis.2009.06.001 | DOI Listing |
Chemistry
January 2025
University of Padova: Universita degli Studi di Padova, Dipartimento di Scienze Chimiche, Via Marzolo 1, 35131, Padova, ITALY.
Chalcogenide exchange reactions are an important class of bimolecular nucleophilic substitution reactions (SN2) involving sulfur and selenium species as nucleophile, central atom, and/or leaving group, which are fundamental throughout redox biology and metabolism. While thiol-disulfide exchange reactions have been deeply investigated, those involving selenium are less understood, especially with regards to the polarised selenenyl sulfides RSe-SR' even though the directed reactivity of selenenyl sulfides is biologically crucial for selenoenzymes such as thioredoxin reductase (TrxR) and glutathione peroxidase (GPx). Synthetic methods to create asymmetric selenenyl sulfides with high regiochemical purity only emerged over the last five years; this functional group has already demonstrated powerful applications to cell biology, through probes for molecular imaging (e.
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December 2024
Department of Biochemistry, Institute of Science, Banaras Hindu University, Varanasi 221005, India.
Lymphatic filariasis (LF) continues to impact 657 million individuals worldwide, resulting in lifelong and chronic impairment. The prevalent anti-filarial medications-DEC, albendazole, and ivermectin-exhibit limited adulticidal efficacy. Despite ongoing LF eradication programs, novel therapeutic strategies are essential for effective control.
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January 2025
Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, Wisconsin, USA.
Variable lymphocyte receptors (VLRs) are the antigen receptors of jawless vertebrates such as lamprey. VLRs are of growing biotechnological interest for their ability to bind certain antigenic targets with higher affinity than traditional immunoglobulins. However, VLRs are disulfide-bonded proteins that are often challenging to produce requiring genetic modifications, fusion partners, non-scalable host cell lines or inclusion body formation and refolding.
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Department of Chemistry and Biochemistry, Faculty of Medicine and Pharmacy, Ibn Zohr University, Laayoune 70000, Morocco.
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January 2025
Department of Life Sciences, National Chung Hsing University, Taichung, 40227, Taiwan.
Ice plant (Mesembryanthemum crystallinum L.) is a halophyte and an inducible CAM plant. Ice plant seedlings display moderate salt tolerance, with root growth unaffected by 200 mM NaCl treatments, though hypocotyl elongation is hindered in salt-stressed etiolated seedlings.
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