• Journal of the Korean Society of Food Science and Nutrition
• /
• v.23 no.1
• /
• pp.110-115
• /
• 1994

To investigate the effect of potato lipoxygenase on the farinograph characteristics of wheat flour dough, composite flours containing enzyme-active potato flor (EPF) and hot-ar dried potato flour(HPF) were used. EPF was made by freeze-drying potato tuber. DPF (denaturated potato flour) was prepared by holding EPF at 8$0^{\circ}C$ for 18 hr in a dry oven. The potato flours were added to wheat flour at a level of 10% , respectivley. EPFB (enzyme-active potato flour blends, 90% wheat flour +105 enzyme -active potato flour) containing lipoxygenase activity gave higher farinogram peak time and higher stability values, lower MTI (mixing tolerance index ) and lower weakness values than those of HPFB(hot-air potato flour blends, 90% wheat flour + 10 % hot-air potato flour). Moreover, then lipoxygenase was added to DPFB(denatured potato flour blends , 90% wheat flour + 10% denatured potato flour) at a level of EPFB, it resulted in increasing stability, peak time and decreasing MTI , weakness at a level of EPFB. When the lipoxugenase was added to wheat flour with fumaric acid at alevel of 6.5 $\times$ 10units/g flour, lipoxygenase overcame the deleterious effects that fumaric acid including activated double-bond compounds have at mixing stability. Also the addition of liposxygenase with linoleic acid to defatted wheat flour resulted in the increase in stability and decrease in MTI value compared with those of linoleic acid and defatted wheat flour.

• Proceedings of the Ginseng society Conference
• /
• 1998.06a
• /
• pp.115-126
• /
• 1998

Four new dammarnae-glycosides named ginsenosides Rgs, Rh4, RsB and Rf2 have been isolated 1'rom Korean red ginseng, the root of Panax ginseng C. A. Meyer (Araliaceae) and their chemical structures have been elucidated by chemical and spectroscopic methods, including'H-'H COSY, HMQC, HMBC, NOESY, as 3-0- [$\beta$-D-glucopyranosyl(1 ~2)-$\beta$-D-glucopyranosyl] dammar-20(22) , B4-diene-3P,12P-diol (ginsenoside Rgs),6-0-$\beta$-D-glucopyranosyl-dammar-20(22),24-diene-3P,6P, 12P-triol (ginsenoside Rh4),3-0- [6" -0-acetyl-D-glucopyranosyl(1 ~2)--D-glucopyranosyl] 20(5)- protopanaxadiol (ginsenoside Rs3) and 6-0- [u-L-rhamno-pyranosyl(1 ~2)-$\beta$-D-glucopyranosyl] dammarane -3$\beta$, 6a, 12 $\beta$, 20(R),25-pentol(ginsenoslde Rfa). The absolute stereo structure of a double bond at C-20(22) was determined as entgegen type by applying NOESY.OESY.

• Bulletin of the Korean Chemical Society
• /
• v.30 no.2
• /
• pp.459-463
• /
• 2009

Furoxanaldehydes possessing phenyl or alkenyl groups at the 3- or 4-position of the furoxan ring were designed for alkyne formation on a solid surface. Furoxans 2 and 3 were prepared from the corresponding alkenes 2a and 3a by the reaction with NaN$O_2$ in acetic acid. Furoxan 4, in which the furoxan ring is conjugated with a double bond, was prepared from bis(bromomethyl)benzene 4a in 5 steps using the Wittig reaction of aldehyde 1 as the key step. The electron beam-mediated fragmentation of furoxanaldehydes 1-4 in a mass spectrometer was exploited by focusing on alkyne formation on the solid surface. The fragmentation of furoxan 3 possessing diaryl groups afforded diarylacetylene at high efficiency, suggesting that the aryl group conjugated with the furoxan ring could facilitate alkyne formation with the evolution of NO.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2008.06a
• /
• pp.429-429
• /
• 2008

The structural stability and the elastic modulus of hexagonal ZnO nanowires and nanotubes are investigated using atomistic simulations based on the shell model. The ZnO nanowire with (10-10) facets is energetically more stable than that with (11-20). Our calculations indicate that the structural change of ZnO nanowires with (10-10) facets is sensitive to the diameter. With decreasing the diameter of ZnO nanowires, the unit-cell length is increased while the bond-length is reduced due to the change of surface atoms. Unlike the conventional layered nanotubes, the energetic stability of single crystalline ZnO nanotubes is related to the wall thickness. The potential energy of ZnO nanotubes with fixed outer and inner diameters decreases with increasing wall thickness while the nanotubes with same wall thickness are independent of the outer and inner diameters. The transformation of single crystalline ZnO nanotubes with double layer from wurtzite phase to graphitic suggests the possibility of wall-typed ZnO nanotubes. The size-dependent Young's modulus for ZnO nanowires and nanotubes is also calculated. The diameter and the wall thickness play a significant role in the Young's modulus of single crystalline ZnO nanowires and nanotubes, respectively.

• Bulletin of the Korean Chemical Society
• /
• v.28 no.6
• /
• pp.941-946
• /
• 2007

Bacillus halodurans O-methyltransferase (BhOMT) is a S-adenosylmethionine (SAM or AdoMet) dependent methyltransferase. Three dimensional structure of the BhOMT bound to S-adenosyl-L-homocysteine (SAH or AdoHcy) has been determined by comparative homology modeling. BhOMT has 40% sequence identity with caffeoyl-CoA 3-O-methyltransferase (CCoAOMT) from alfalfa. Based on x-ray structure of CCoAOMT, three dimensional structure of BhOMT was determined using MODELLER. The substrate binding sites of these two proteins showed slight differences, but these differences were important to characterize the substrate of BhOMT. Automated docking study showed that four flavonoids, quercetin, fisetin, myricetin, and luteolin which have two hydroxyl groups simultaneously at 3'- and 4'-position in the B-ring and structural rigidity of Cring resulting from the double bond characters between C2 and C3, were well docked as ligands of BhOMT. These flavonoids form stable hydrogen bondings with K211, R170, and hydroxyl group at 3'-position in the Bring has stable electrostatic interaction with Ca2+ ion in BhOMT. This study will be helpful to understand the biochemical function of BhOMT as an O-methyltransferase for flavonoids.

• Archives of Pharmacal Research
• /
• v.19 no.6
• /
• pp.551-553
• /
• 1996

A genuine dammarane glycoside, named ginsenoside $Rg_{5}$, has been isolated by repeated column chromatography and preparative HPLC from the MeOH extract of Korean red ginseng (Panax ginseng C.A. Meyer). The chemical structure of ginsenoside$ Rg_{5}$ was determined as $3-O-[{\beta}-D-glucopyranosyl (1{\rightarrow}2)-{\beta}-D-glucopyranosyl]$ dammar-20(22), $24-diene-3{\beta},12{\beta}-diol$ by spectral and chemical methods. The stereostructure of a double bond at C-20(22) of ginsenoside $Rg_{5}$ was characterized as (E) from the chemical shift of C-21 in the $^{13}C-NMR $and a NOESY experiment in the $^{1}H-NMR$.

• Archives of Pharmacal Research
• /
• v.21 no.4
• /
• pp.452-457
• /
• 1998

Three compounds, 5-(acetoxymethyl)-5-(hydroxymethyl)-3-tetradecyl-2,5-dihydro-2-furanone (3), 5-(acetoxymethyl)-5-(hydroxymethyl)-3,3-dihexyltetrahydro-2-furanone (4) and 5-(acetoxymethyl)-5-(hydroxymethyl)-3,3-dioctyltetrahydro-2-furanone (5), were designed and synthesized as surrogates of the ultrapotent DAG analogue, 5-(acetoxymethyl)-5-(hydroxymethyl) 3-[(Z)-tetradecylideneltetrahydro-2-furanone (1), a compound that showed high affinity for PKC-$\alpha$ ($K_1$=35 nM) in a competition binding assay with [$^3H$-20]phorbol-12,13-dibutyrate (PDBU). In an attempt to overcome the problem of generating geometrical E- and Z- isomers, as encountered with 1, the double bond was moved to an endocyclic location as in 3, or an additional alkyl chain was appended to C3 to give the corresponding 3,3-dialkyl saturated lactones (4 and 5). The lactone was constructed from glycidyl-4-methoxyphenyl ether in 5 steps. The target compounds showed reduced binding affinities for PKC-.alpha. with $K_{i}$ values of 192 nM (3), 4,829 nM (4), and 2,812 nM (5), respectively. These results indicate that constrained DAG analogues having a tetrahydro-2-furanone template are effectively discriminated by PKC-(X in terms of the direction of the long alkyl chain connected to the 3-position.n.

• Journal of Life Science
• /
• v.10 no.2
• /
• pp.210-217
• /
• 2000

A kinetic profile of the catalytic domain of stromelysin-1 (SCD) using the fluorescent peptide substrate has been determined by the stopped-flow technique. The pH profile has a pH optimum of about 5.5 with an extended shoulder above pH 7. Three pKa values, 5.0, 5.7, and 9.8 are found for the free enzyme state and two pH independent Kcat/Km values of 4.1$\times$104 M-1 s-1 and 1.4$\times$104 M-1 s-1 at low and high pH, respectively. The profile is quite different in shape with other MMP family which has been reported, having broad pH optimum with two pKa values. The substrate specificity of SCD towards fluorescent heptapeptide substrates has been also examined by thin layer chromatography. The cleavage sites of the substrates have been identified using reverse-phase HPLC method.SCD cleaves Dns-PLA↓L↓WAR and Dns-PLA↓L↓FAR at two positions. However, the Dns-PLA↓LRAR, Dns-PLE↓LFAR, adn Dns-PLSar↓LFAR are cleaved exclusively at one bond. The double cleavages of Dns-PLALWAR and Dns-PLALFAR by SCD are in marked contrast to the close structurally related matrilysin. A notable feature of SCD catalysis agrees with the structural data that the S1' pocket of SCD is deeper than that of matriysin. The differences observed between SCD and matrilysin may form the basis of understanding the structural relationships and substrate specificities of the MMP family in vivo.

• Journal of Technologic Dentistry
• /
• v.35 no.4
• /
• pp.313-320
• /
• 2013

Purpose: The purpose of this study was to know the physical properties of UDMA dental composite resins containing two photosensitizers, PD, DA, as a photosensitizer instead of CQ. We want to know Remaining Double Bond(RDB) of UDMA unfilled resin and diametral tensile strength and flexural strength of composite resin containing PD and DA were compared with those of CQ, most widely used photosensitizer for dental composite resins. Methods: The RDB of UDMA studied by FT-IR spectroscopy increased with irradiation time. The composite resins were tested for their physical properties. The dental composite resins were made with UDMA as a monomer, silanized silica as filler, N,N-dimethylaminoethyl methacrylate (DAEM) as amine initiator, and one of the two kinds of new photosensitizers. Results: The relative RDB of UDMA was in the order: DA > CQ > PD but the physical properties of the composite resins show PD and DA with higher results compared with that containing CQ. The reason for the results is that PD and DA serve not only as a photosensitizer but also as a photo-crosslinking agent. Conclusion: PD and DA show as effective photosensizers, suitable for UDMA dental composite resin compare with a higher efficiency than CQ.

• Nuclear Engineering and Technology
• /
• v.9 no.1
• /
• pp.39-44
• /
• 1977

The configuratior and conformation of N-methyl-C-phenylalkyl-ketimine isomers, Ph-CR=N$CH_3$ (R=H, $CH_3$, $CH_3$CH$_2$), have been studied from extended Huckel molecular orbital calculations. The result shows that the E-configuration of the C=N double bond is favored compared with that of the Z-configuration. The most preferable conformation of the phenyl ring rotamer in N-methyl-C-phenylaldimine and N-methyl-C-phenylmethylketimine are the coplanar forms with regard to the C=N plane, but the conformation of the $CH_3$CH$_2$-rotamer, in N-methyl-C-phenylethyl-ketimine, the gauche form (dihedral angle between C=N and $CH_3$CH$_2$- plane=90$^{\circ}$) is favored.