• BMB Reports
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• v.30 no.3
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• pp.211-215
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• 1997

A photoactive analog of ATP, 3'(2')-O-(p-azidobenzoyl)-adenosine 5-triphosphate (AB-ATP) was synthesized by chemically coupling N-hydroxysuccinimidyl-4-azidobenzoate (NHS-AB) and ATP. The utility of AB-ATP as an effective active-site-directed photoprobe was demonstrated using catalytic subunit of protein kinase A as a model enzyme. Photoincorporation of AB-ATP was saturated with apparent dissociation constant of $30{\mu}m$ and protected completely by $100{\mu}m$ of ATP. When the enzyme was covalently modified by photolysis in the presence of saturating amounts of photoprobe, about 60% inhibition of enzyme activity was observed. These results demonstrate that AB-ATP has potential application as a probe to characterize ATP-binding proteins including protein kinases.

• BMB Reports
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• v.29 no.3
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• pp.205-209
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• 1996

To investigate the role of heparin in keratinocyte growth factor (KGF) and acidic fibroblast growth factor (aFGF) high affinity binding to the KGF receptor (KGFR), a cell free system was established which utilized a secreted chimeric molecule between the KGFR extracellular domain and the immunoglobulin heavy chain Fc domain (KGFR-HFc). KGFR-HFc was purified from NIH 3T3 cells and demonstrated the binding of $[^3H]-heparin$ as well as heparin Sepharose. Scatchard analysis showed that the dissociation constant for heparin binding to KGFR-HFc was 140 nM. High affinity KGF and aFGF binding to KGFR-HFc remained unchanged after treatment with 0.6 M NaCl, which is the concentration sufficient to release any bound heparin to the KGFR-HFc. These results strongly suggest that although the KGFR interacts with heparin, the presence of heparin is not absolutely required for high affinity binding of either KGF or aFGF to the KGFR.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.11 no.2
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• pp.97-100
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• 2005

To delay the fermentation of Kimchi during storage and handling, adipic acid, was selected due to its low acid dissociation constant. Sensory evaluation was conducted to find maximum dosage of adipic acid which does not influence the raw taste of Kimchi and 0.12%(wt. of adipic acid/wt. of Kimchi) was selected. At $10^{\circ}C$, the optimum and maximum shelf life was respectively 3.2 and 2.3 times longer than that of control. At 15 and $20^{\circ}C$, extension of shelf life was as follows: maximum shelf life with adipic acid was extended about 2.3-2.7 times and optimum shelf life was 1.3-1.5 times.

• Journal of Microbiology and Biotechnology
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• v.7 no.4
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• pp.242-249
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• 1997

Stability of bioluminescence was investigated with Photobacterium phosphoreum immobilized on the strontium alginate in order to develope continuous real time monitoring of pollutants. The stability of bioluminescence emission was improved by prolonged aging time. The aging time of ${\geq}40$ min and the cell concentration of ${\leq}0.6\;of\;OD_660$ were selected for the immobilization of P. phosphoreum to give linearity between cell concentrations and bioluminescence intensity. In sensitivity tests using phenol, it was found that this compound quenched bioluminescence proportional to the concentration without lowering of cell growth. The lower value for maximum quenching ($q_s$) and higher dissociation constant ($K_s$) were observed with strontium-alginate immobilized cells compared to free cells. The response of bioluminescence to toxicants was evaluated with the immobilized luminescent bacteria. The sensitivity of the immobilized cells was found to be good in response to toxicants, 4-nitrophenol, salicylate and cadmium, when evaluated with a specific rate of bioluminescence quenching.

• Analytical Science and Technology
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• v.14 no.3
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• pp.286-289
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• 2001

The effect of pH and the substrate concentration on the sensing ability of the chicken peroxidase enzyme electrode was examined quanititatively. Using the new Michaelis-Menten equation, to which pH concept was introduced, enabled to calculate all kinds of dissociation constant related to chicken peroxidase and subsequently to determine the optimum pH of the sensor.

• International Journal of Aeronautical and Space Sciences
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• v.9 no.2
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• pp.9-17
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• 2008

When the stagnation temperature of the combustion chamber or ambient air increases, the specific heats and their ratio do not remain constant any more, and start to vary with this temperature. The gas remains perfect, except, it will be calorically imperfect and thermally perfect. A new generalized form of the Prandtl Meyer function is developed, by adding the effect of variation of this temperature, lower than the threshold of dissociation. The new relation is presented in the form of integral of a complex analytical function, having an infinite derivative at the critical temperature. A robust numerical integration quadrature is presented in this context. The classical form of the Prandtl Meyer function of a perfect gas becomes a particular case of the developed form. The comparison is made with the perfect gas model for aim to present a limit of its application. The application is for air.

• International Journal of Aeronautical and Space Sciences
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• v.9 no.1
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• pp.1-30
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• 2008

When the stagnation temperature of a perfect gas increases, the specific heats and their ratio do not remain constant any more and start to vary with this temperature. The gas remains perfect; its state equation remains always valid, except, it is named in more by calorically imperfect gas. The aim of this work is to trace the profiles of the supersonic axisymmetric Minimum Length Nozzle to have a uniform and parallel flow at the exit section, when the stagnation temperature is taken into account, lower than the dissociation threshold of the molecules, and to have for each exit Mach number and stagnation temperature shape of nozzle. The method of characteristics is used with the algorithm of the second order finite differences method. The form of the nozzle has a point of deflection and an initial angle of expansion. The comparison is made with the calorically perfect gas. The application is for air.

• YAKHAK HOEJI
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• v.28 no.3
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• pp.129-138
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• 1984

Specific [$^{3}H$] ouabain binding and $Ca^{2+}$ -uptake were measured to elucidate the role of high affinity [$^{3}H$] ouabain binding site in rat cardiac myocytes which contain 65% of rod cells. High affinity [$^{3}$H] ouabain binding site, which is about 3% of total pump sites, with apparent dissociation constant ($K_{D}$) of $1.1{\times}10^{-7}M$ and maximum binding site concentration (Bmax) of 1.2 pmol/mg protein ($1.754{\times}10^{5}cells$) were identified. At the concentration of $10^{-7}M$ to $10^{-4}M$, ouabain produced concentration dependent increase in $Ca^{2+}$-uptake of myocytes. The effect of ouabain on $Ca^{2+}$-uptake was not effected by membrane depolarization (elevated K+ in incubation medium) or verapamil. These results suggest that in rat ventricular myocytes the ouabain receptor complex to high affinity site may increase Na+ - $Ca^{2+}$ exchange across the sarcolemmal membrane by inhibition of Na+, K+ - ATPase.

• The Korean Journal of Zoology
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• v.37 no.4
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• pp.495-503
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• 1994

Hemolymph SHBP (hJHBP) was partially purified from last instar larvae of Bombyx zori by gel filtration and their optimal reaction conditions of dextrin coated charcoal binding assay were determined. Dissociation constant (KD) of hJHBP for JH III was calculated to be 1.45 $\times$ 10-7 M at $4^{\circ}C.$ The molecular weight of hJHBP was estimated to be 30 kDa by gel filtration on a calibrated Sephadex G-100 column and 33 kDa by SDS-PAGE. These results indicate that hSHBP consists of a single polvpeptide chain. Isoelectric point of hJHBP was found to be pH 5.1 and 19 of the first 20 amino acid residues were determined from N-terminus of purified hJHBP.

• Environmental Analysis Health and Toxicology
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• v.12 no.3_4
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• pp.75-84
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• 1997

Chromatographic retention behavior and separation of various phenol derivatives on a Partisil 10 ODS 3 column-with mobile phase containing $\alpha$-cyclodextrin-were systematically studied. The decrease in k' values caused by the addition of cyclodextrins in the mobile phase was based on the formation of an inclusion complex, resulting in weakening of the hydrophobic interaction between solutes and the stationary phase. The content of the organic solvent in the mobile phase also influenced k' values of the solutes, and k' values increased with a decrease of the content of organic solvent in the mobile phase. A simple equation has been derived that reveals the hyperbolic dependence of the capacity factor on the total concentration of cyclodextrin. A plot of the reciprocal of the capacity factor against (CD)$_T$ gives a straight line and the dissociation constant, K$_D$, of the inclusion complex can be calculated from the slope. The capacity factor decreased with increasing temperature. The enthalpy was calculated from the slope of van't Hoff plots. Under optimum conditions, some mixtures of phenol derivatives were able to separated successfully.