• Korean journal of food and cookery science
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• v.8 no.3
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• pp.333-341
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• 1992

The physicochemical, rheological and sensory characteristics of 'BACKSULGIES', which was added with potato peel, guar gum or polydextrose, were investigated. The maximum acceptable addition ratio of dietary fiber to 'BACKSULGI' was 10%. And optimal addition ratio was 3% for all samples. The water binding capacity was affected by dietary fiber sources and incubation conditions (temperature and time). The Guar gum had me highest value of water binding capacity. The solubility was highly related with water binding capacity and me swelling power was increased with temperature increment. The degree of gelatinization was not significantly different with dietary fiber sources. But me values of gelatinization of 'BACKSULGIES' added with dietary fibers were significantly higher than mose of 'BACKSULGI' with no dietary fiber. Generally hardness and brittleness incresed along with storage time. But me hardness of 'BACKSULGIES' added with dietary fibers was significantly lower man those of 'BACKSULGI' with no dietary fiber. The retardation effect of dietary fibers for retrogradation of 'BACKSULGIES' was also proved by time constant determination of Avrami equation. Sernsory evaluation revealed that me addition of dietary fibers did not reduce the organoreptic quality. Therefore potato peel 3%, guar gum 3%, polydextrose 3% were optimum addition ratio which could be accepted as conventional 'BACKSULGI'. As me results of this study, it was proved mat the additions of dietary fibers to 'BACKSULGI' had the retardation effect of retrogradation.

• Journal of Microbiology and Biotechnology
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• v.25 no.4
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• pp.503-510
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• 2015

The iLOV protein belongs to a family of blue-light photoreceptor proteins containing a light-oxygen-voltage sensing domain with a noncovalently bound flavin mononucleotide (FMN) as its chromophore. Owing to advantages such as its small size, oxygen-independent nature, and pH stability, iLOV is an ideal candidate over other reporter fluorescent proteins such as GFP and DsRed. Here, for the first time, we describe the feasibility of applying LOV domain-based fluorescent iLOV as a metal sensor by measuring the fluorescence quenching of a protein with respect to the concentration of metal ions. In the present study, we demonstrated the inherent copper sensing property of the iLOV protein and identified the possible amino acids responsible for metal binding. The fluorescence quenching upon exposure to Cu²⁺ was highly sensitive and exhibited reversibility upon the addition of the metal chelator EDTA. The copper binding constant was found to be 4.72 ± 0.84 µM. In addition, Cu²⁺-bound iLOV showed high fluorescence quenching at near physiological pH. Further computational analysis yielded a better insight into understanding the possible amino acids responsible for Cu²⁺ binding with the iLOV protein.

• Biomolecules & Therapeutics
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• v.3 no.1
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• pp.21-27
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• 1995

The only compounds with antagonistic activity via AT$_1$receptor, one of two subtypes of angiotensin II (AII) receptor, have been demonstrated to block the vasoconstriction effects of AII and thereby provide therapeutic potential. This initiated the search for compounds with high specific affinity to AT$_1$receptor and their effective screening methods. The radioligand binding assay for the AII receptor is regarded as the primary method for the evaluation of AT$_1$receptor antagonists for their activity. In this paper, we characterized the liver AT$_1$receptor and describe the efficient method of the radioligand binding assay using rat liver as a source of AT$_1$receptor. Equilibrium binding studies with rat adrenal cortex, adrenal medulla, liver and bovine adrenal showed that the specific bindings of [$^3$H] AII were saturable in all tissues and the Scatchard plots of those data were linear, suggesting a single population of binding sites. Hill slopes were very near to the unity in all tissues. Kinetic studies of [$^3$H) AII binding in rat liver homogenates yielded two association rate constants, 4.10$\times$10$^{7}$ M$^{-1}$ min$^{-1}$ and 4.02$\times$10$^{9}$ M$^{-1}$ min$^{-1}$ , with a single dissociation rate constant, 7.07$\times$10$^{-3}$ min-$^{-1}$ , possibly due to the partial dissociation phenomenon. The rank order of inhibition potencies of [$^3$H] AII binding in rat liver was AII>Sarile>Losartan>PD 123177. Rat liver homogenates revealed to have very high density of homogeneous population of the AT$_1$receptor subtype, as the specifically bound [$^3$H] AII was not inhibited by PD 123177, the nonpeptide antagonist of AT$_2$. The results of this study demonstrated that the liver homogenates from rats could be the best receptor preparation for the AT$_1$receptor binding assay and provide an efficient system for the screening of newly synthesized candidate compounds of AT$_1$receptor antagonist.

• Journal of Environmental Science International
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• v.7 no.5
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• pp.653-658
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• 1998

Marine algaes are capable of binding a large quantity of heavy metals. We have investigated the uptake capacity of Pb and Cu by using 22 species of marine algae. collected from Korean coast. Among a variety of different marine algae types for biosorbent potential. Kjellmaniella crassifolia showed the highest uptake capacity of Pb. Metal uptake of Pb and Cu by Kjellmaniella crassifolia increase as the initial concentration rises, as long as binding sites are remained. The metal uptake parameters for Pb and Cu had been determined according to Langmuir and Freundlich model. By increasing pH, Pb uptake was increased and Cu uptake was constant. The maximum uptake capacity of Pb and Cu by Kjellmaniella crassifolia was 437 mg/g and 129 mg/g, respectively.

• The Korean Journal of Zoology
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• v.37 no.3
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• pp.318-323
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• 1994

The association of replication origins/termini with nuclear matrix during S phase was investigated by DNase digestion of halo structures in synchronized mouse LPI-1 cells. The binding of parental DNA to nuclear matrix was constant throughout S phase. When nuclear matrix was isolated from the cells pulse-labeled with 3H-thvmidine at various stases of S phase, total 3H-labels associated with nuclear matrix were specifically higher at So, Sa and Ss stages than other stases of S phase, suggesting that the newly synthesized DNAs at those stages are not excluded out of nuclear matrix. Similar patterns were obsenred from the pulse-chase experiments, in which cells were pulse-labeled at each stage of S phase and further incubated for 1 hr. These results suggest that the replication origins and termini are fixed at the nuclear matrix, and that the nuclear matrix binding fractions of DNA at 3C-pause may contain a large population of replication origins and termination sites.

• Bulletin of the Korean Chemical Society
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• v.24 no.1
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• pp.45-48
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• 2003

A novel fluorimetric method has been developed for the determination of microgram quantities of bovine serum albumin (BSA) based on its enhancement effect of Nile Blue fluorescence at 670 nm, caused by binding of Nile Blue to BSA to produce a stable water soluble complex. The binding constant of micromole Nile Blue-BSA complex was estimated by Scatchard plot method. Under the optimal conditions, the increased fluorescence intensity was linearly related to BSA concentration in the range of 0.5-12.0 ㎍/mL. The detection limit was 0.2 ㎍/mL, and the relative standard deviation of six replicate measurements was 1.4% for 10.0 ㎍/mL BSA. There was little interference from amino acids, sugars and most of metal ions.

• Bulletin of the Korean Chemical Society
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• v.25 no.6
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• pp.829-832
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• 2004

The pure product of 2,3-diaminophenazine was prepared by the enzyme-catalyzed reaction of ophenylenediamine-$H_2O_2$-horseradish peroxidase and characterized by UV/Vis spectroscopy, IR spectroscopy and NMR spectroscopy. The electrochemical behaviour of 2,3-diaminophenazine on the glassy carbon electrode was studied. The interaction between 2,3-diaminophenazine and deoxyribonucleic acid was studied by cyclic voltammetry method and UV/Vis spectroscopy, which indicated that the interaction between them is intercalation. The influence of reacting time was also studied. The binding ratio of the 2,3-diaminophenazine-DNA complex is calculated to be 1 : 2 and the binding constant is to be $5.07{\times} 10^3L{\cdot}mol^{-1}$ at room temperature.

• Microbiology and Biotechnology Letters
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• v.23 no.3
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• pp.316-321
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• 1995

Some properties of $\beta$-1, 3-glucan synthase system in Saccharamyces cerevisiae were investigated. By extraction with detergent and salt, the membrane preparations could be dissociated into two components, one soluble, the other still membrane bound. Both components, in addition to GTP, were necessary for the activity of $\beta$-1, 3-glucan synthase like other fungi. The protective effect of guanosine nucleotides on the soluble factor pointed to the possibility that this fraction contained a GTP-binding protein. Addition of increasing amounts of soluble factor to a constant amount of insoluble catalytic factor, vice versa, gave rise to a saturation curve. These results, including different types of evidence, indicate that the soluble factor and the catalytic factor form a complex.

• Bulletin of the Korean Chemical Society
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• v.16 no.12
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• pp.1153-1162
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• 1995

The conformational details of β-lactose are investigated through molecular dynamics simulations in conjunction with the adiabatic potential energy map. The adiabatic energy map generated in vacuo contains five local minima. The lowest energy structure on the map does not correspond to the structure determined experimentally by NMR and the X-ray crystallography. When aqueous solvent effect is incorporated into the energy map calculation by increasing the dielectric constant, one of the local minima in the vacuum energy map becomes the global minimum in the resultant energy map. The lowest energy structure of the energy map generated in aquo is consistent with the one experimentally determined. Molecular dynamics simulations starting from those fivelocal minima on the vacuum energy map reveal that conformational transitions can take place among various conformations. Molecular dynamics simulations of the lactose and ricin B chain complex system in a stochastic boundary indicate that the most stable conformation in solution phase is bound to the binding site and that there are conformational changes in the exocyclic region of the lactose molecule upon binding.

• Journal of Microbiology and Biotechnology
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• v.8 no.6
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• pp.656-662
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• 1998

To make a distinction between the influence of the dielectric constant and of methanol concentration on trypsin-catalyzed hydrolysis and methanolysis at $0^{\circ}C$, a model reaction of $N^u$-benzyloxycarbonyl-L-lysine p-nitrophenyl ester with water-methanol mixtures was chosen and a kinetic study done. The $k_{cat}$ values increased with methanol concentration, in a linear manner whereas $K_{M}$ values increased in a log-linear fashion. However, the $k_{cat},$_{M}$ ratio increased at lower methanol concentrations than 30% and then began to decrease at higher concentrations. The decrease in $k_{catK_M}$observed at higher than 30% methanol concentrations is attributed to the hydrophobic partitioning effect on substrate binding. On the other hand, the increase in $k_{catK_M}$ in the 0~30% methanol concentration range seems to be due to the effect of nucleophilic cosolvent on $k_{cat}$ and of the dielectric constant on $k_m$. This explanation was verified by measuring the effect of varying the dielectric constant of the medium on kinetic constants with isopropyl alcohol chemically unrelated to the enzyme reaction as the methanol concentration is maintained at a constant level. Therefore, we conclude that the effect of increasing the methanol concentration in the model reaction on the kinetic parameters $k_{cat \;and\;{K_M}}$ is caused by changes in both the nucleophilicity and the dielectric constant of the medium. Based on product analysis, the increase in $k_4, k_3$by decreasing the temperature can be accounted for by the suppression of hydrolytic reactions. This observation indicates that the nucleophile is favored by low temperatures. There was no loss of trypsin activity over a 10 h period in 60% methanol concentration at $pH^＊\; 5.5,\; 0^{\circ}C$.EX>.