• KSBB Journal
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• v.5 no.2
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• pp.125-131
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• 1990

Microbial production of L-phenylalanine using Corynebacterium glutamicum ATCC 21674, a tyrosine auxotroph resistant to aromatic amino acid analogues, has been studied and kinetic analysis was performed. Even though the strain was reported as a tyrosine auxotroph, it produced tyrosine and was able to grow on the minimal medium where no tyrosine was present. The average specific growth rate at the exponential growth phase was 0.087 hr-1. There was a dissociation of growth from the formation of the product. Linear correlation between biomass production and total CO2 production was obtained. The relationship between CO2 evolution rate and sugar consumption rate was also found to be linear.

• Elastomers and Composites
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• v.50 no.3
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• pp.175-183
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• 2015

A series of fluorinated aromatic poly(hydroxyamide)s (PHAs) were synthesized by direct polycondensation of diacides containing 2,6-dimethylphenoxy group and quinoxaline ring in the main chain with 2,2-bis-(3-amino-4-hydroxyphenyl) hexafluoropropane. The PHAs had relatively low inherent viscosities in the range of 0.35~0.43 dL/g at $35^{\circ}C$ in DMAc solution. All PHAs exhibited excellent solubility in aprotic solvents such as NMP, DMAc, DMF and DMSO as well as in common organic solvents such as pyridine, THF, and m-cresol at room temperature. However, the poly(benzoxazole)s (PBOs) were quite insoluble in all organic solvents except partially soluble in concentrated sulfuric acid. The PBOs showed glass transition temperatures between 233 and $284^{\circ}C$ by DSC and maximum weight loss temperatures in the range of $536-546^{\circ}C$ by TGA.

• Bulletin of the Korean Chemical Society
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• v.22 no.11
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• pp.1236-1242
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• 2001

(3S,1'S)-3-(1'-Carboxy-2'-phenyl)ethylamino-2-oxetanone (1a) and (3R,1'S)-3-(1'-carboxy-2'-phenyl)ethylamino-2-oxetanone (1b) were designed, synthesized, and evaluated as inhibitors for carboxypeptidase A, a prototypical zinc protease that removes the C-terminal amino acid having an aromatic side chain from oligopeptide substrate. It was concluded from the analysis of inhibition kinetics that while 1a inactivates CPA irreversibly, its diastereoisomer, 1b is a weak competitive inhibitor for CPA. A possible explanation for the observed difference in inhibition mode that is dependent on the inhibitor stereochemistry is offered.

• Food Science and Preservation
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• v.31 no.1
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• pp.197-198
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• 2024

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.2
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• pp.319-325
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• 1999

Volatile flavor compounds in Korean salt fermented shrimp on the market were analyzed by vacuum simultaneous distillation solvent extraction/gas chromatography/mass spectrometry/olfac tometry(V SDE/GC/MS/O) and aroma extract dilution anlaysis(AEDA). A total of 32 volatile com pounds were detected by GC/O analysis. Of these, 18 were positively identified, and composed of S containing compounds(5), aldehydes(4), ketones(3), N containing compounds(3), ester(1), alcohol(1) and aromatic hydrocarbon(1). Predominant odorants(Log3FD$\geq$4) in salt fermented shrimp were 2,3 butanedione(sour/buttery), 1 octen 3 one(earthy/mushroom like), dimethyl trisulfide(cooked cabbage /soy sauce like) and 2 acetylthiazole(grainy/nutty). Predominant free amino acids were aspartic acid, glutamic acid(sour and umami taste), arginine, methionine(bitter) and lysine(sweet and bitter) in evaluation of taste value.

• Applied Chemistry for Engineering
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• v.22 no.5
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• pp.579-581
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• 2011

Spectroscopic evaluation of hair chemical damage was performed by SEM/EDS, CLSM, and FT-IR spectroscopy. In SEM/EDS, hydrogen peroxide treated hair showed the loose packing of surface scales, lower ratio of sulfur element and higher ratio of oxygen atom. In the optical single section by using CLSM, high fluorescent intensity appeared in untreated hair. However, in case of treated hair, low fluorescent intensity appeared. This results the aromatic amino acids which can be autofluorescent were more abundant than bleached hair. FT-IR spectra showed that cysteic acid band intensity was increased by performing the bleaching treatments. These results indicate that the oxidative damage cleaves the S-S bond and results in the lower working force of hair fiber.

• Microbiology and Biotechnology Letters
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• v.30 no.1
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• pp.8-14
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• 2002

Pseudomonas sp. S-47 is capable of degrading 4-chlorobenzoate to produce 5-chloro-2-hydroxymuconic semialdehyde (5C-2HMS) by the enzymes encoding by xylXYZLTE cluster. In this study, the resulting 5C-2HMS was confirmed to be transformed to 5-chloro-2-hydroxymuconic acid (5C-2HMA) by 5C-2HMS dehydrogenase. The xylG gene encoding 5C-2HMS dehydrogenase was cloned from the chromosomal DNA of strain S-47. The nucleotide sequence of xylG showed to be composed of 1,600 base pairs with ATG initiation and TGA termination codons. A deduced amino acid sequence of the 5C-2HMS dehydrogenase (XylG) exhibited 98％, 93％, and 89％ identity with those of the dehydrogenases from P. putida mt-2, P. putida G7, and Pseudomonas sp. CF600, respectively.

• BMB Reports
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• v.38 no.1
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• pp.115-119
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• 2005

Replacement of valine by tryptophan or tyrosine at position $\alpha$96 of the $\alpha$ chain ($\alpha$96Val), located in the ${\alpha}_1{\beta}_2$ subunit interface of hemoglobin leads to low oxygen affinity hemoglobin, and has been suggested to be due to the extra stability introduced by an aromatic amino acid at the $\alpha$96 position. The characteristic of aromatic amino acid substitution at the $\alpha$96 of hemoglobin has been further investigated by producing double mutant r Hb ($\alpha$42Tyr$\rightarrow$ Phe, $\alpha$96Val$\rightarrow$Trp). r Hb ($\alpha$42Tyr$\rightarrow$Phe) is known to exhibit almost no cooperativity in binding oxygen, and possesses high oxygen affinity due to the disruption of the hydrogen bond between $\alpha$42Tyr and $\beta$99Asp in the ${\alpha}_1{\beta}_2$ subunit interface of deoxy Hb A. The second mutation, $\alpha$96Val$\rightarrow$Trp, may compensate the functional defects of r Hb ($\alpha$42Tyr$\rightarrow$Phe), if the stability due to the introduction of trypophan at the $\alpha$96 position is strong enough to overcome the defect of r Hb ($\alpha$42Tyr$\rightarrow$Phe). Double mutant r Hb ($\alpha$42Tyr$\rightarrow$Phe, $\alpha$96Val$\rightarrow$Trp) exhibited almost no cooperativity in binding oxygen and possessed high oxygen affinity, similarly to that of r Hb ($\alpha$42Tyr$\rightarrow$Phe). $^1$H NMR spectroscopic data of r Hb ($\alpha$42Tyr$\rightarrow$Phe, $\alpha$96Val$\rightarrow$Trp) also showed a very unstable deoxy-quaternary structure. The present investigation has demonstrated that the presence of the crucible hydrogen bond between $\alpha$42Tyr and $\beta$99Asp is essential for the novel oxygen binding properties of deoxy Hb ($\alpha$96Val$\rightarrow$Trp).

• The Korean Journal of Pharmacology
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• v.26 no.1
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• pp.1-6
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• 1990

We established an in vitro system of central serotonergic neurons by culturing dissociated rat embryonic (El4) brainstem cells to 14 days in vitro and monitored the serotonergic neuronal growth by measuring 5-hydroxytryptamine (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) contents in the cells with hish performance liquid chromatography with electrochemical detection (HPLC-EC). We studied also tile effects of various drugs on the contents of 5-HT and 5-HIAA, confirming in vivo reports. The 5-HT content (13 ng/mg protein) and 5-HT turnover rate (17 pmol/mg protein/h) at 14 days in vitro were in good agreement with those reported in the adult rat brain. The 5-HT content was more easily depleted with p-chlorophenylalanine, a tryptophan hydroxylase inhibitor than with NSD 1015 (3-hydroxybenzylhydrazine), an aromatic L-amino acid decarboxylase (AADC) inhibitor. Incubation of the cultures with tryptophan or 5-hydroxytryptophan increased the rate of serotonin formation implying that neither tryptophan hydroxylase nor AADC is saturated with its amino acid substrate in this in vitro system . The 5-HT content was depleted by reserpine. The 5-HT and 5-HIAA contents were increased and decreased, respectively, by monoamine oxidase inhibitors. All the above results indicate that the biochemical properties of the central serotonergic neurons in this culture system reflect reliably those of central serotonergic neurons in vivo. We suggest that measuring 5-HT and 5-HIAA contents in the primary cultured dissociated brainstem-cells with HPLC-EC is useful in the study of pharmacology as well as toxicolgy of the central serotonergic neurons.

• Korean Journal of Environmental Agriculture
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• v.36 no.3
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• pp.175-183
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• 2017

BACKGROUND:The Aromatic rice which is characterized by the flavor of Nurungji when cooked rice, and consumption is increasing recently. The purpose of this study was to investigate the physicochemical characteristics and aroma components of five aromatic rice cultivars according to transplanting time. METHODS AND RESULTS: Quantitative analysis of protein, fat, fatty acid and essential amino acid for five aroma rice cultivars(Hyangmibyeo 2 ho, Aromi, Mihyang, Aranghyangchal, Heughyang)and transplanting time was analyzed by crude protein analyzer, gas chromatography (GC), liquid chromatography (LC) and viscosity analysis was done by using rapid viscosity analyzer (RVA). The content of 2-acetyl-1-pyrroline (2AP) was determined by gas chromatography mass spectrometer. (GC-MS) As a result, the average protein and lipid contents were 6.5% and 2.4%, respectively. The content of essential amino acid showed the highest content at 104.4mg/g. There was no significant change in normal nutrients during the transplanting time. By RVA, cv.Hyangmibyeo 2 ho showed the highest peak and total setback viscosities and lowest breakdown viscosity in early transplantation. The content of 2AP in flavor varieties and transplanting time was quantitatively analyzed by GC-MS. Among the cultivars, Aromi showed the highest 2AP contents at $66.7{\mu}g/100gin$ normal transplanting time. CONCLUSION: cv.Aromi and Hyangmibyeo 2 ho were excellent physicochemical properties and 2AP components contents amongaromatic rice cultivars tested. Theiroptimaltime to transplant was at the beginning of June in the area of Miryang.