Copper amine oxidases (CAOs) catalyse the oxidation of various aliphatic amines to the corresponding aldehydes, ammonia and hydrogen peroxide. Although CAOs from various organisms share a highly conserved active-site structure including a protein-derived cofactor, topa quinone (TPQ), their substrate specificities differ considerably. To obtain structural insights into the substrate specificity of a CAO from Arthrobacter globiformis (AGAO), we have determined the X-ray crystal structures of AGAO complexed with irreversible inhibitors that form covalent adducts with TPQ. Three hydrazine derivatives, benzylhydrazine (BHZ), 4-hydroxybenzylhydrazine (4-OH-BHZ) and phenylhydrazine (PHZ) formed predominantly a hydrazone adduct, which is structurally analogous to the substrate Schiff base of TPQ formed during the catalytic reaction. With BHZ and 4-OH-BHZ, but not with PHZ, the inhibitor aromatic ring is bound to a hydrophobic cavity near the active site in a well-defined conformation. Furthermore, the hydrogen atom on the hydrazone nitrogen is located closer to the catalytic base in the BHZ and 4-OH-BHZ adducts than in the PHZ adduct. These results correlate well with the reactivity of 2-phenylethylamine and tyramine as preferred substrates for AGAO and also explain why benzylamine is a poor substrate with markedly decreased rate constants for the steps of proton abstraction and the following hydrolysis.
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http://dx.doi.org/10.1093/jb/mvr125 | DOI Listing |
Chem Rec
January 2025
Bioinspired & Biomimetic Inorganic Chemistry Laboratory, Department of Chemistry, National Institute of Technology Calicut, Kozhikode, Kerala, 673601, India.
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School of Materials and Physics & Center of Mineral Resource Waste Recycling, China University of Mining and Technology, Xuzhou, Jiangsu, 221116, China.
Designing spent graphite anodes from lithium-ion batteries (LIBs) for applications beyond regenerated batteries offers significant potential for promoting the recycling of spent LIBs. The battery-grade graphite, characterized by a highly graphitized structure, demonstrates excellent conductive loss capabilities, making it suitable for microwave absorption. During the Li-ion intercalation and deintercalation processes in battery operation, the surface layer of spent graphite (SG) becomes activated, forming oxygen-rich functional groups that enhance the polarization loss mechanism.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Chemistry, Johns Hopkins University, 3400 N. Charles St., Baltimore, Maryland 21218, United States.
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View Article and Find Full Text PDFAcc Chem Res
January 2025
Department of Chemistry, University of California, Berkeley, California 94720, United States.
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View Article and Find Full Text PDFBlood Coagul Fibrinolysis
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Department of Hematology, The Second Affiliated Hospital, Chongqing Medical University, Jiangnan, Chongqing, China.
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