Monoclonal antibodies were prepared against a transition state analog inhibitor of chorismate mutase (EC 5.4.99.5). One of the antibodies catalyzes the rearrangement of chorismate to prephenate with rate accelerations of more than 2 orders of magnitude compared to the uncatalyzed reaction. Saturation kinetics were observed, and at 25 degrees C the values of kcat and Km were 1.2 X 10(-3) s-1 and 5.1 X 10(-5) M respectively. The transition state analog was shown to be a competitive inhibitor of the reaction with Ki equal to 0.6 microM. These results demonstrate the feasibility of using rationally designed immunogens to generate antibodies that catalyze concerted reactions.
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http://dx.doi.org/10.1073/pnas.85.14.4953 | DOI Listing |
J Am Chem Soc
January 2025
Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea.
A series of Ni complexes bearing a redox and acid-base noninnocent tetraamido macrocyclic ligand, H-(TAML-4) {H-(TAML-4) = 15,15-dimethyl-5,8,13,17-tetrahydro-5,8,13,17-tetraaza-dibenzo[]cyclotridecene-6,7,14,16-tetraone}, with formal oxidation states of Ni, Ni, and Ni were synthesized and characterized structurally and spectroscopically. The X-ray crystallographic analysis of the Ni complexes revealed a square planar geometry, and the [Ni(TAML-4)] complex with the formal oxidation state of Ni was characterized to be [Ni(TAML-4)] with the oxidation state of the Ni ion and the one-electron oxidized TAML-4 ligand, TAML-4. The Ni oxidation state and the TAML-4 radical cation ligand, TAML-4, were supported by X-ray absorption spectroscopy and density functional theory calculations.
View Article and Find Full Text PDFOrg Lett
January 2025
School of Pharmacy, Sungkyunkwan University, Suwon 16419, Republic of Korea.
The stereoselective synthesis of highly substituted cyclobutanes is essential for the development of lead candidates in drug discovery. Herein, we present a novel Rh(III)-catalyzed reaction pathway for synthesizing substituted cyclobutanes, which involves a concerted N-C bond formation and C-C bond cleavage between 2-aryl quinazolinones and alkylidenecyclopropanes. Notably, the combination of Rh(III) catalyst and HFIP solvent plays a critical role in facilitating the formation of cyclobutane rings.
View Article and Find Full Text PDFJ Phys Chem B
January 2025
Department of Applied Chemistry, Graduate School of Science and Engineering, Doshisha University, Kyotanabe, Kyoyo 610-0321, Japan.
Excited-state proton transfer (ESPT) reactions of 5-cyano-2-naphthol (5CN2) and 5,8-dicyano-2-naphthol (DCN2) were investigated in protic ionic liquids (PILs) composed of quaternary ammonium (NH) ( = 2, 4, or 8) and hexanoate (CHCOO) using time-resolved fluorescence spectroscopy. The effects of the number of alkyl carbons in the cation and the basicity of the anion on the reaction yield and dynamics were examined. In a series of [NH][CHCOO], fluorescence from the hydrogen-bonding complex (AHBX) of a proton-dissociated form (RO) with a solvent acid in the electronic excited state was observed between the fluorescence bands of an acidic form (ROH) and an anionic form (RO) as in the case of [NH][CFCOO] (Fujii et al.
View Article and Find Full Text PDFJ Phys Chem A
January 2025
School of Applied Science and Humanities, Haldia Institute of Technology, ICARE Complex, Haldia 721657, India.
This study explores the reactivity of a new intermolecular P/B frustrated Lewis pair in the context of dinitrogen activation through a push-pull mechanism. The ab initio molecular dynamics model known as atom-centered density matrix propagation plays a pivotal role in elucidating the weakly associated encounter complex. In-depth analysis, mainly through intrinsic reaction coordinate calculations, supports a single-step mechanism.
View Article and Find Full Text PDFChemistry
January 2025
Indian Institute of Technology Delhi, Department of Chemistry, Hauz Khas, 110016, New Delhi, INDIA.
A mononuclear CoIII complex (1) of a bisamide-bisalkoxide donor ligand was synthesized and thoroughly characterized. The reaction of 1 with 0.5 equiv.
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