Spatial structure, thermodynamics and kinetics of formation of hydrazones derived from pyridoxal 5′-phosphate and 2-furoic, thiophene-2-carboxylic hydrazides in solution
“…However, the loss of 31 P NMR signal quality was much less as phosphate remains dissolved. 31 P NMR chemical shifts obtained for hydrazones are in good agreement with the previously reported data: 3.85 ppm for PLP-F2H (3.83 ppm), 28 3.68 ppm for PLP-T2H (3.69 ppm), 28 3.80 ppm for PLP-3NH (3.76 ppm) 10 and 3.77 ppm for PLP-PRZ (3.79 ppm). 29 At pH 10, phosphate exists in the solution as HPO 4 2predominantly.…”
Section: Resultssupporting
confidence: 91%
“…4-Nitrophenol (4NP) of unknown origin was twice recrystallized from ethanol and dried on air. Hydrazones were synthesized from PLP and corresponding hydrazides as described: PLP-3NH, 10 PLP-F2H, PLP-T2H, 28 and PLP-PRZ. 29 The impurities' absence was controlled using 1 H NMR spectroscopy.…”
The present paper reports on the study of the dephosphorylation of pyridoxal 5′phosphate and four derived hydrazones (containing the residues of pyrazine, 2furan, 2-thiophene, 3-pyridine carboxylic acids) induced by bovine alkaline phosphatase from intestinal mucosa at 298.2 K and pH 10 (0.05 m Tris-HCl buffer).We observed and discussed characteristic changes in the UV-vis and fluorescent spectra of substrates. Michaelis-Menten parameters of the enzymatic dephosphorylation are calculated. The stability of alkaline phosphatase in the presence of hydrazones is confirmed. The dephosphorylation of the Zn(II) complex with pyridoxal 5′-phosphate-derived hydrazone is analyzed.
“…However, the loss of 31 P NMR signal quality was much less as phosphate remains dissolved. 31 P NMR chemical shifts obtained for hydrazones are in good agreement with the previously reported data: 3.85 ppm for PLP-F2H (3.83 ppm), 28 3.68 ppm for PLP-T2H (3.69 ppm), 28 3.80 ppm for PLP-3NH (3.76 ppm) 10 and 3.77 ppm for PLP-PRZ (3.79 ppm). 29 At pH 10, phosphate exists in the solution as HPO 4 2predominantly.…”
Section: Resultssupporting
confidence: 91%
“…4-Nitrophenol (4NP) of unknown origin was twice recrystallized from ethanol and dried on air. Hydrazones were synthesized from PLP and corresponding hydrazides as described: PLP-3NH, 10 PLP-F2H, PLP-T2H, 28 and PLP-PRZ. 29 The impurities' absence was controlled using 1 H NMR spectroscopy.…”
The present paper reports on the study of the dephosphorylation of pyridoxal 5′phosphate and four derived hydrazones (containing the residues of pyrazine, 2furan, 2-thiophene, 3-pyridine carboxylic acids) induced by bovine alkaline phosphatase from intestinal mucosa at 298.2 K and pH 10 (0.05 m Tris-HCl buffer).We observed and discussed characteristic changes in the UV-vis and fluorescent spectra of substrates. Michaelis-Menten parameters of the enzymatic dephosphorylation are calculated. The stability of alkaline phosphatase in the presence of hydrazones is confirmed. The dephosphorylation of the Zn(II) complex with pyridoxal 5′-phosphate-derived hydrazone is analyzed.
“…We estimate the standard deviation of finding rexp as ±3%, which agrees to previous reports describing the NOESY analysis [65,68]. Thus, the inaccuracy of finding the conformer populations can be calculated, as it was made for small molecules in [42]. Based on the NOESY data with corresponding errors, the conformers fractions for ibuprofen are 48 and 52% ( Figure 6) with the accuracy of ±3%.…”
Section: Conformer Distribution From the Noesy Datasupporting
confidence: 87%
“…An alternative method is the NMR spectroscopy at high pressures, which has shown its usefulness in studies of molecular structure [24][25][26], host-guest interactions [27], metalorganic framework [28,29], ionic liquids [30][31][32], aqueous geochemistry [33][34][35][36] and operando studies of complex mixtures [37]. In addition, liquid state NMR spectroscopy is useful in studies of conformational exchange [38][39][40][41][42]. However, conducting NMR experiments under supercritical conditions requires a specialized high-pressure supercritical cell.…”
high-pressure NMR 2D NOESY supercritical fluid molecular structure conformers MD simulation
A B S T R A C TAn experimental approach in conducting NMR measurements at supercritical parameters of state is discussed. A novel design of the high-pressure NMR cell was developed which allowed eliminating the field inhomogeneity and, thus, increasing the sensitivity of the experiment at the supercritical state.Analysis of the MD simulations and NMR data showed that two conformers of ibuprofen dominate in the solution in supercritical CO2 along the critical isochore 1.3 ρcr(CO2). Conformer populations calculated from MD simulations and from NMR spectra agree with each other
“…As well as the information of hydrazones structure in the solution might also be valuable since isometry and equilibria also affect the biochemical properties of compounds. [31] DFT calculations have previously been used to provide accurate predictions of the energy barrier in different organic molecules. [11,32,28] The optimized geometry parameters of conformer 2 and 3 at the B3LYP/6-311++G level of computation and the implicit solvent model to simulate CHCl 3 are listed in Tables S1-S4 from the supporting information.…”
Section: Conformational Analysis: Vt 1 H Nmr and Dftmentioning
We employed (Z)‐N'‐[phenyl(pyrimidin‐2‐yl)methylene]nicotinohydrazide (2) and (Z)‐4‐(dimethylamino)‐N'‐[phenyl(pyrimidin‐2‐yl)methylene]benzohydrazide (3) as cores of dynamic chemical systems whose different states are modulated, in a reversible fashion, through specific physical and chemical stimuli. The structure of the compounds was determined by Nuclear Magnetic Resonance (NMR) techniques (1D and 2D) and confirmed by single‐crystal X‐ray diffraction. By Variable temperature (VT) 1H NMR experiments and DFT calculations, the conformational isomerism of 2 was studied and added as an additional input for the dynamic system. Additionally, 2 exhibits configurational E/Z isomerization mediated by pH variations and UV light. On the other hand, configurational isomerism locks an unlocks a tridentate pocket for metal cation coordination in both 2 and 3. All the different dynamic states configurational/conformational isomerism and locked and unlocked coordination constitute a development in the field of systems of multiple dynamics suitable for molecular machines.
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