• Proceedings of the Korean Magnetic Resonance Society Conference
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• 1999.02a
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• pp.2-3
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• 1999

• Journal of the Korean Chemical Society
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• v.19 no.3
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• pp.149-155
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• 1975

Pivalic acid, which has a globular shape and is a plastic crystal, has been examined by means of temperature-dependent with-line proton magnetic resonance spectroscopy. Results of temperature-dependent line width, second moment, and spin-lattice relaxation time studies of pivalic acid were interpreted in terms of dynamic behavior and hydrogen bonding. The dynamic behavior consists of superimposed reorientation of the methyl groups about their three-fold axes$(C_3) and of the molecule about the central C-C bond(C_3'),$ general molecular reorientation about the center of gravity, and molecular self-diffusion. Activation energies for the motional processes have been obtained from line width measurements using the modified Bloembergen, Purcell, and Pound theory and from spin-lattice relaxation time measurements. The results were compared with the Pople-Karasz theory of fusion and the agreement was found to be poor. The discrepancy was interpreted in terms of hydrogen bonding in this molecule.

• BMB Reports
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• v.49 no.9
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• pp.497-501
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• 2016

Wide-line ¹H NMR intensity and differential scanning calorimetry measurements were carried out on the intrinsically disordered 73-residue full transactivation domain (TAD) of the p53 tumor suppressor protein and two peptides: one a wild type p53 TAD peptide with a helix pre-structuring property, and a mutant peptide with a disabled helix-forming propensity. Measurements were carried out in order to characterize their water and ion binding characteristics. By quantifying the number of hydrate water molecules, we provide a microscopic description for the interactions of water with a wild-type p53 TAD and two p53 TAD peptides. The results provide direct evidence that intrinsically disordered proteins (IDPs) and a less structured peptide not only have a higher hydration capacity than globular proteins, but are also able to bind a larger amount of charged solute ions.

• Bulletin of the Korean Chemical Society
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• v.19 no.9
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• pp.942-947
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• 1998

The >$^13C$ NMR spectrum of >$^13CO$ adsorbed on Pd particles varies dramatically depending on dispersion. The spectrum of highly dispersed Pd particles supported on silica is a powder pattern ∼800 ppm wide with a first moment of 410 ppm. A low dispersion sample has a motionally narrowed line centered at 750±30 ppm and only ∼85 ppm full width at half height (FWHH). Over several years, high dispersion samples show an increase in the intensity near 750 ppm. These observations are interpreted as an increase of mobile bridging CO on high dispersion Pd surfaces of particles which resulted from smoothing of the metal particle surfaces in the presence of CO.

• Korean Journal of Plant Resources
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• v.27 no.6
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• pp.610-621
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• 2014

Phenolic compounds such as isoflavones contribute to the antioxidant properties of soybean. This study investigated differences in the phenolic content and antioxidant activity of ten soybean cultivars grown in two different locations in Korea. We observed a wide range of variation in total isoflavone and phenolic content by location and cultivar. The total isoflavone content of cultivars grown at Pyeongchang (sub-highland) was significantly higher than that in cultivars grown at Gangneung (lowland). In contrast, the total phenolic content of cultivars grown at Gangneung was greater than that of cultivars grown at Pyeongchang. The radical scavenging activity of DPPH was similar to that of the total phenolic content rather than that of the total isoflavone content. These results suggest that antioxidant activity of soybean was associated with phenolic compounds rather than isoflavones. To identify the individual antioxidant components, we used an on-line HPLC-$ABTS^+$-based assay system, ESI/MS, and NMR. The results showed that the strongest antioxidant activity was linked to epicatechin.