• Bulletin of the Korean Chemical Society
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• v.16 no.11
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• pp.1079-1084
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• 1995

New cyclophanes having multilactam linkages were synthesized and characterized. One-pot coupling reaction of 2,6-pyridinedicarbonyl dichloride and a diamine gave a tetralactam, a hexalactam, and a octalactam in good yields. The TLC behaviour, the molecular symmetry shown by 1H NMR spectrum, and the fragmentation patterns shown by FAB mass spectrum of the octalactam support its monocyclic structure.

• Microbiology and Biotechnology Letters
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• v.20 no.5
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• pp.565-573
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• 1992

We isolated Actinomycetes strain No. 1882-5, which produces the inhibitor on the bleb formation of K562 cell induced by phorbol ester, from soil sample. Through solvent extraction, Amberlite XAD-4, silica and Lobar low pressure LC, antifungal antibiotic MT 1882-1 and bleb forming inhibitor MT 1882-II were purified from strain No. 1882-5. MT 1882-1 was identified as piericidin $A_{1}$($C_{25}H_{37}0_4N$, M.W. 415) and MT 1882-11 as glucopiericidin A($C_{31}H_{47}0_9N$, M.W. 577) from the analysis of physico-chemical properties and UV, $^1H-NMR$, $^13C-NMR$, and mass spectra of these compounds.

• Journal of the Korean Magnetic Resonance Society
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• v.7 no.1
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• pp.37-45
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• 2003

Human CD99 is a ubiquitous 32-kDa transmembrane protein encoded by mic2 gene. Recently it has been reported that expression of a splice variant of CD99 transmembrane protein (Type I and Type II) increases invasive ability of human breast cancer cells. To understand structural basis for cellular functions of CD99 Type II, we have initiated studies on hCD99$\^$TMcytoI/ using circular dichroism (CD) and multi-dimensional NMR spectroscopy. CD spectrum of hCD99$\^$TMytoI/ in the presence of 200mM DPC and CHAPS displayed an existence ${\alpha}$-helical conformation, showing that it could form an ${\alpha}$-helix under membrane environments. In addition, we have found that the cytoplasmic domain of CD99 would form symmetric dimmer in the presence of transmembrane domain. Although it has been rarely figured out the correlation between structure and functional mechanism of hCD99$\^$TMcytoI/, the dimerization or oligomerization would play an important role in its biological function.

• KSBB Journal
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• v.11 no.5
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• pp.536-542
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• 1996

The isolation of active compounds showing the inhibitory effect on glucosyltransferase(GTase) from cacao bean husk(CBH) extract was carried out for screening of anti-plaque agents. These active compounds were purified by additional column chromatography of MCI-gel CHP-20 and Sephadex LH-20 and their chemical structures were determined by NMR and mass spectroscopy. Two compounds showing the inhibitory effect on GTase from CBH extract were obtained. These compounds showed positive reactions with anisaldehyde-H2SO4 solution and FeCl3, and were identified as dimeric flavan-3-ols on TLC. By NMR and MS data analyses, the structures of two different flavan-3-ols were identified as procyanidin B-1 and procyanidin B-3, respectively.

• Applied Biological Chemistry
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• v.38 no.6
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• pp.577-580
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• 1995

During the screening for the antimicrobial agents against multidrug-resistant Staphylococcus aureus, we isolated an active compound produced by strain CNU30122. The active compound was purified from culture broth by HP-20 column chromatography, ethylacetate extraction. silica gel column and Sephadex LH-20 column chromatographies and HPLC. Based on various NMR studies including $^1H-^1H\;COSY$, $^1H-^{13}C\;COSY$ and HMBC experiments. the active compound was identified as fusidic acid.

• Korean Journal of Food Science and Technology
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• v.35 no.3
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• pp.503-509
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• 2003

For the development of the anti-obesity natural drug, the inhibitor of adipocyte differentiation was screened from Korean traditional medicinal plants. Phellodendri Cortex was selected as a candidate of adipocyte differentiation inhibitor. An inhibitory compound PC-4 was purified from the methanol (MeOH) extract of Phellodendri Cortex using silica gel and ODS RP-18 column chromatography and HPLC. PC-4 was obtained as yellow powder; UV ${\lambda}_{max}$ (MeOH): 230, 260, 340 and 430 nm. The chemical structure of PC-4 was determined as an isoquionoline alkaloid, berberine, on the basis of various NMR experiments including $^1H-\;and\;^{13}C-NMR$. The PC-4 inhibited the differentiation of preadipocyte NIH-3T3 L1 cells at a concentration of $1\;{\mu}g/mL$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.428-429
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• 2005

Novel fluoroionophore of dibenzothiazolyl-dibenzo-crown ethers were synthesized from diformal-dibenzo 18-crown-6 (24-crown-8) with 2-aminothiophenol, and they were characterizated by $^1H$-NMR, $^{13}C$-NMR, IR spectrum, Mass spectrum, elemental analyses, respectively. The fluorescent properties of the newly synthesized crown ether were examined with $Li^+$, $Na^+$, $K^+$, $Rb^+$, $Cs^+$, $NH_4^+$ and $CF_3COOH$, respectively. With protonation using $CF_3COOH$, the absorption bands of the new crown ethers are further blue shifted, the maximum emission wavelengths further red shifted.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.4
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• pp.325-330
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• 2000

Alginate obtained from brown algae had various physicochemical and rheological properties and could used as a dietary fiber, However, alginate has not been widely applied to the food industry, since it had high viscosity, high gelling effect conjugated with some mineral, and low solubility. To improve functionality of alginate, partially develymerized alginates, which was water-soluble dietary fiber were obtained by hydrolysis of alginate from the sea tangle, Laminaria japonicus, heated at $121^{\circ}C$. Effects of depolymerization of alginate on the changes of viscosity and average molecular weight, block composition ratio of mannuronate to guluronate (M/G ratio), chemical properties using $PT-IR, ^1H-NMR, and ^(13)C-NMR$ spectrum were investigated. The average molecular weight and viscosity of the alginate were rapidly decreased with the thermal decomposition, and estimated to be 1,307,415 dalton and 284,000 cps, before heating, 728,106 and 3,940.29 cps after 30 min heating, 102,635 and 22.22 cps after 2.5 hrs heating, 51,205 and 12.05 cps after 3 hrs, and 10,049 and 4.28 cps after 6.5 hrs, respectively. The M/G ratio was increased with the heating time, while MM-block did not show any changes and GG-block diminished. The results of $FT-IR, ^1H-NMR and ^(13)C-NMR$ spectrum suggested that changes of molecular structure did not occur by the thermal decomposition.

• Applied Biological Chemistry
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• v.50 no.3
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• pp.233-237
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• 2007

The roots of Brassica campestris ssp rapa were extracted with 80% aqueous MeOH, and the concentrated extract was partitioned with EtOAc, n-BuOH and $H_{2}O$. From the EtOAc and n-BuOH fractions, five compounds were isolated through the repeated silica gel column chromatographies. From the result of spectroscopic data including NMR and MS, the chemical structures of the compounds were determined as palmitic acid methyl ester (1), linolenic acid methyl ester (2), linoleic acid methyl ester (3), ${\beta}-sitosterol$ (4) and daucosterol (5).

• Analytical Science and Technology
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• v.26 no.1
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• pp.61-66
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• 2013

The activity of an antimicrobial peptide, protegrin-1, on the well-aligned lipid bilayer deposited on a thin coverglass plate was investigated by $^2H$ solid-state NMR spectroscopy. Orientational distribution and molecular motion in the lipid bilayer were determined from $^2H$ solid-state NMR spectrum. Reorientational motion of lipid molecules in the vacuum-dried state was found to be small but their orientational distribution was not able to be determined. As storage times were longer, the order of the alignment of lipid molecules in the lipid bilayer and percentages involved in the toroidal pore structures increased. We found that much longer time is required to get the equilibrium state of the peptide-lipid mixture under our experimental condition for investigating the action of the antimicrobial peptide like protegrin-1 on the lipid bilayers deposited on the thin coverglass plates.