The degradation of unsaturated fatty acids by beta-oxidation involves Delta(3),Delta(2)-enoyl-CoA isomerases (enoyl-CoA isomerases) that catalyze 3-cis --> 2-trans and 3-trans --> 2-trans isomerizations of enoyl-CoAs and the 2,5 --> 3,5 isomerization of dienoyl-CoAs. An analysis of rat liver enoyl-CoA isomerases revealed the presence of a monofunctional enoyl-CoA isomerase (ECI) in addition to mitochondrial enoyl-CoA isomerase (MECI) in mitochondria, whereas peroxisomes contain ECI and multifunctional enzyme 1 (MFE1). Thus ECI, which previously had been described as peroxisomal enoyl-CoA isomerase, was found to be present in both peroxisomes and mitochondria. This enzyme seems to be identical with mitochondrial long-chain enoyl-CoA isomerase (Kilponen, J.M., Palosaari, P.M., and Hiltunen, J.K. 1990. Biochem. J. 269, 223-226). All three hepatic enoyl-CoA isomerases have broad chain length specificities but are distinguishable by their preferences for one of the three isomerization reactions. MECI is most active in catalyzing the 3-cis --> 2-trans isomerization; ECI has a preference for the 3-trans --> 2-trans isomerization, and MFE1 is the optimal isomerase for the 2,5 --> 3,5 isomerization. A functional characterization based on substrate specificities and total enoyl-CoA isomerase activities in rat liver leads to the conclusion that the 3-cis --> 2-trans and 2,5 --> 3,5 isomerizations in mitochondria are catalyzed overwhelmingly by MECI, whereas ECI contributes significantly to the 3-trans --> 2-trans isomerization. In peroxisomes, ECI is predicted to be the dominant enzyme for the 3-cis --> 2-trans and 3-trans --> 2-trans isomerizations of long-chain intermediates, whereas MFE1 is the key enzyme in the 2,5 --> 3,5 isomerization.
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http://dx.doi.org/10.1074/jbc.M112228200 | DOI Listing |
J Org Chem
January 2025
Department of Chemistry, New York University, 100 Washington Square East, New York, New York 10003, United States.
Nucleophilic substitution reactions of C-2-acyloxy furanosyl acetals can be highly diastereoselective. We here show that the presence of a less electron-donating -nitrobenzoyloxy group at C-2 of a furanosyl acetal can be of use to control the 1,2- stereoselectivity of acetal substitution reactions with higher stereoselectivity than the analogue with the more electron-donating benzoyloxy group, just as what was observed in the pyranosyl system. Computational results support a reaction manifold involving both open oxocarbenium ions and -dioxolenium ions to provide the 1,2- and 1,2- products.
View Article and Find Full Text PDFbioRxiv
December 2024
Laboratory of Mitochondrial Biology in Human Health and Disease, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, New York 10029, USA.
Mitochondria maintain a biochemical environment that cooperates with BH3-only proteins (e.g., BIM) to potentiate BAX activation, the key event to initiate physiological and pharmacological forms of apoptosis.
View Article and Find Full Text PDFJ Cell Biol
January 2025
State Key Laboratory of Virology, RNA Institute, College of Life Sciences and Frontier Science Center for Immunology and Metabolism, Wuhan University, Wuhan, China.
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and severe acute respiratory syndrome coronavirus (SARS-CoV) exhibit differences in their inflammatory responses and pulmonary damage, yet the specific mechanisms remain unclear. Here, we discovered that the SARS-CoV-2 nucleocapsid (N) protein inhibits the activation of the nuclear factor-κB (NF-κB) pathway and downstream signal transduction by impeding the assembly of the transforming growth factor β-activated kinase1 (TAK1)-TAK1 binding protein 2/3 (TAB2/3) complex. In contrast, the SARS-CoV N protein does not impact the NF-κB pathway.
View Article and Find Full Text PDFChem Sci
December 2024
State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Nankai University Tianjin 300071 China
1,2--Aryl furanosides are prevalent in nature and exhibit significant biological activities. The 1,2- configuration is less favorable in terms of stereoelectronic and steric effects, making the synthesis of this type of skeleton highly challenging. Traditional methods for the synthesis of 1,2--aryl furanosides usually require complicated protection manipulations, resulting in lengthy synthetic routes and low overall efficiency.
View Article and Find Full Text PDFChempluschem
November 2024
Department of Catalysis and Chemical Reaction Engineering, National Institute of Chemistry, Hajdrihova 19, SI-1000, Ljubljana, Slovenia.
Electrochemical reduction reaction of CO (eCORR) to produce valuable chemicals offers an attractive strategy to solve energy and environmental problems simultaneously. We have mapped out entire reaction pathways of eCORR to CO on Cu(100), including all intermediates and transition states using first-principles simulations. To accurately account for the solvent effect, the reaction was investigated with and without explicit water molecules, highlighting the limitations of the often (mis)used vacuum reaction pathway simplification.
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