• Food Science and Preservation
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• v.30 no.6
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• pp.1029-1042
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• 2023

This study aimed to apply the technology of increasing the volatile aromatic compounds in wine through mixed fermentation of Saccharomyces cerevisiae and non-Saccharomyces yeasts to make distilled soju. The expectation was to induce changes in metabolites such as volatile aromatic compounds before the distillation process, followed by concentrating these compounds through distillation to enhance the odor property of distilled soju. Additionally, the study aimed to examine the impact of mixed fermentation with S. cerevisiae and non-Saccharomyces yeasts on distilled soju's free amino acid content. As a result, when Hanseniaspora uvarum yeast was used, there was an increase in the content of low molecular weight volatile aroma compounds, particularly esters. Distilled soju co-fermented with S. cerevisiae and H. uvarum SJ69 exhibited similar amino acid content to distilled soju single-fermented with S. cerevisiae. However, distilled soju co-fermented with S. cerevisiae and H. uvarum S6, a decrease in amino acid content. Sensory evaluation results indicated a higher odor score in distilled soju co-fermented with S. cerevisiae and H. uvarum S6, suggesting that the mixed fermentation technology utilizing H. uvarum could contribute to improving the quality of distilled soju in the future.

• Journal of Plant Biotechnology
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• v.30 no.2
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• pp.207-214
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• 2003

This study was carried out to establish a novel bioassay system for screening of compounds affecting aromatic amino acid or anthocyanin biosynthesis through investigating a degree of sucrose-induced anthocyanin formation such as size of plant material, buffer conditions, light intensity and irradiated duration, incubation temp., etc were determined and standard procedure (suitable experimental condition) was set up as follows. The second leaf blade of white corn seeding induced by fluridone treatment were segmented into a size of 5${\times}$5 min. The segments were floated on the solution of 1% sucrose in 1.0mM MES buffer (pH6.0∼6.5) and incubated at 26$^{\circ}C$ for 2days under the continuous light condition(70∼100$\mu$mol m$^{-2}$ s$^{-1}$ ). Anthocyanin in the purpled tissues was extracted with methanol containing 1% HCl and the optical density of the clear supematants was determined at 528mm. Influences of some chemicals were tested using this system. Glyphosate, 5-enolpyruvylshikimate 3-phosphate synthase inhibitor, showed most sensitive response with I$_{50}$ value at 3.3$\mu$M. Dicyclohexylcarbodiimide(DCCD) and parachloromercuribenzenesulfonic acid(PCMBS) had a relatively strong ingibition with I50 value at 7.1$\mu$M and 10.2$\mu$M, respectively. These results show that sucrose-induced anthocyanin formation in white com leaf segment provide a very simple and rapid system for searching new compounds affecting aromatic amino acid or anteocyanin biosynthesis by screening at less than 10$\mu$M.

• BMB Reports
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• v.28 no.4
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• pp.363-367
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• 1995

E. coli methionyl-tRNA synthetase is one of the class I tRNA synthetases. The Tryptophane residue at the position 461 located in the C-terminal domain of the enzyme is a key amino acid for the interaction with the anticodon of $tRNA^{Met}$. W461 was replaced with other amino acids to determine the chemical requirement for the interaction with the anticodon of $tRNA^{Met}$. Saturation mutagenesis at the position 461 generated a total of 12 substitution mutants of methionyl-tRNA synthetase. All the mutants showed the same in vivo stability as the wild-type enzyme, suggesting that the amino acid substitutions did not cause severe conformational change of the protein The mutants containing tyrosine, phenylalanine, histidine and cysteine substitutions showed in vivo activity while all the other mutants did not. The comparison of the in vitro aminoacylation activities of these mutants showed that aromatic ring structure, Van der Waals volume and hydrogen bond potential of the amino acid residue at the position 461 are the major determinants for the interaction with the anticodon of $tRNA^{Met}$.

• Korean Journal of Pharmacognosy
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• v.34 no.1 s.132
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• pp.55-59
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• 2003

The effects of liriodenine, an aporphine isoquinoline alkaloid, on dopamine content in PCl2 cells were investigated. Treatment of PC12 cells with liriodenine decreased dopamine content in a dose-dependent manner (33.6% inhibition at $10\;{\mu}M$ for 12 h). The $IC_{50}$ in value of liriodenine was $8.4\;{\mu}M$. Dopamine content decreased at 3 h and reached a minimal level at 12 h after the exposure to liriodenine. Under these conditions, the activities of tyrosine hydroxylase and aromatic L-amino acid decarboxylase were also inhibited at $10\;{\mu}M$ of liriodenine by 10.1% and 20.2% relative to control, respectively. In addition, liriodenine inhibited the increase in dopamine content induced by L-DOPA Treatments $(50-100\;{\mu}M)$ in PC12 cells. These results suggest that liriodenine inhibited dopamine biosynthesis and L-DOPA-induced increase in dopamine content by reducing the activities of tyrosine hydroxylase and aromatic L- amino acid decarboxylase in PC12 cells.

• Bulletin of the Korean Chemical Society
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• v.19 no.10
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• pp.1105-1109
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• 1998

A chiral stationary phase derived from (S)-N-(3,5-dinitrobenzoyl)leucine N-phenyl N-alkyl amide (CSP 2) was applied in separating the two enantiomers of various π-basic aromatic derivatives of leucine N-propyl amide in order to evaluate π-basic aromatic groups as an effective derivatizing group for the resolution of a-amino acids. Subsequently N-(3,5-dimethoxybenzoyl) group was found to be very effective as a π-basic aromatic derivatizing group. Based on these results, N-(3,5-dimethoxybenzoyl) derivatives of various a-amino N-propyl amides, N,N-diethyl amides and esters were resolved on the CSP derived from (S)-N-(3,5-dinitrobenzoyl) leucine N-phenyl N-alkyl amide (CSP 2) and the resolution results were compared with those on the CSP derived from (S)-N-(3,5-dinitrobenzoyl)leucine N-alkyl amide (CSP 1). The enantioselectivities exerted by CSP 2 were much greater than those exerted by CSP 1. In addition, racemic N-(3,5-dimethoxybenzoyl)-a-mino N,Ndiethyl amides were resolved much better than the corresponding N-(3,5-dimethoxybenzoyl)-a-mino N-propyl amides and esters on both CSPs. Based on these results, a chiral recognition mechanism utilizing the π-π donor-acceptor interaction and the two hydrogen bondings between the CSP and the analyte was proposed.

• Korean Journal of Weed Science
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• v.10 no.3
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• pp.227-232
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• 1990

The effects of alachlor [2-chloro-2', 6' diethyl-N-(methoxymethyl) acetanilide] treatment on nucleic acid, amino acid and protein synthesis were studied. The amide herbicide alachlor blocks the biosynthesis of the amino acids isoleucine, valine and aromatic amino acid in oat root tips. Nucleic acid was inhibited, but was not proportional to reduction in protein synthesis. $1{\times}10^{-4}M$ of alachlor treatment of oat roots inhibited 36% DNA synthesis, but DNA synthesis was not inhibited at $1{\times}10^{-5}M$. RNA synthesis was inhibited by $1{\times}10^{-5}M$ and $1{\times}10^{-4}M$ of alachlor 16 and 27%, respectively, while inhibition of protein synthesis did occur at same concentrations. Inhibition of protein synthesis also did not occur at concentration below $1{\times}10^{-4}M$ alachlor. It suggest that inhibition of protein sythesis caused significantly by alachlor($1{\times}l0^{-3}M$) result from secondary action.

• Journal of Microbiology and Biotechnology
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• v.18 no.1
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• pp.48-54
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• 2008

A putative ${\omega}$-aminotransferase gene, cc3143 (aptA), from Caulobacter crescentus was screened by bioinformatical tools and overexpressed in E. coli, and the substrate specificity of the ${\omega}$-aminotransferase was investigated. AptA showed high activity for short-chain ${\beta}$-amino acids. It showed the highest activity for 3-amino-n-butyric acid. It showed higher activity toward aromatic amines than aliphatic amines. The 3D model of the ${\omega}$-aminotransferase was constructed by homology modeling using a dialkylglycine decarboxylase (PDB ID: 1DGE) as a template. Then, the ${\omega}$-aminotransferase was rationally redesigned to increase the activity for 3-amino-3-phenylpropionic acid. The mutants N285A and V227G increased the relative activity for 3-amino-3-phenylpropionic acid to 3-amino-n-butyric acid by 11-fold and 3-fold, respectively, over that of wild type.

• Analytical Science and Technology
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• v.25 no.3
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• pp.171-177
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• 2012

A determination method of aromatic amino acids such as trytophan (Trp), tyrosine (Tyr), and phenylalanine (Phe) using luminol-$H_2O_2$-Cu(II) system has been presented. In the presence of an aromatic amino acid, the enhanced chemiluminescence (CL) intensity of luminol-$H_2O_2$-Cu(II) system was obtained by forming a complex between Cu(II) and the amino acid. Based on the above phenomenon, a sensitive and fast determination of three aromatic amino acids was performed using the CL method in batch-type detection system. To optimize determination conditions, the kinetic influence of an aromatic amino acid on the luminol-$H_2O_2$-Cu(II) system and the effects of $H_2O_2$ and Cu(II) concentration, pH, and buffers were investigated. Under the optimized conditions, the calibration curve was linear over the range from $1.0{\times}10^{-6}$ to $2.0{\times}10^{-5}\;M$ for Trp, $1.0{\times}10^{-6}$ to $2.0{\times}10^{-5}\;M$ for Try, and $2.0{\times}10^{-6}$ to $2.0{\times}10^{-5}\;M$ for Phe, respectively. In this range, reproducibility (RSD, n = 4) of Trp, Try, and Phe were 3.21%, 2.64%, and 2.48%, respectively. The limit of detection ($3{\sigma}/s$) was calculated to be $6.8{\times}10^{-7}\;M$ for Trp, $5.7{\times}10^{-7}\;M$ for Try, and $9.6{\times}10^{-7}\;M$ for Phe.

• Korean Journal of Microbiology
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• v.33 no.4
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• pp.247-251
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• 1997

Effects of amino acids on the lactic acid bacteria in kimchi were studied. 73 different lactic acid bacteria have been isolated during the kimchi fermentation at $15^{\circ}C$. Among these bacteria, dextran formers were occupied by 69.9%, of which Leuconostoc and Lactobacillus were 4.1% and 65.8%, respectively. All isolates didn't grow in a medium added with 500 ppm of tyrosine, whereas such an inhibition was not exhibited in kimchi with the same concentration of tyrosine. In kimchi added with tyrosine the lactic acid bacteria were less diverse than in the natural kimchi but the ratio of dextran formers were similar. As contrasted with natural kimchi, Leuconostoc was rather increased up to 41.4% and Lactobacillus was decreased down to 29.3%. Dominant species in each genus were Leu. mesenteroides and Lac. minor. Thus it is believed that tyrosine had inhibition effect for the growth of most Lactobacillus in kimchi.

• Archives of Pharmacal Research
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• v.21 no.6
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• pp.723-728
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• 1998

The chemical behaviours of 4-methyl-2-oxo-2H-benzopyran-7-yl oxoacetyl hydrazine (2) towards some different reagents such as anhydride compounds, aromatic aldehydes, carb on disulphide, and nitrous acid yielded the corresponding pathalazine derivatives (3, 4, 5), hydrazone derivative (6), 1,3,4-oxadiazole derivative (7, 8, 9) and acid azide (10) respectively. Treatmen of 10 with absolute alcohols, amines and ethyl amino acid ester gave the corresponding carbamate derivative (11), substituted urea derivative (12) and ethyl substituted alkyl acetate (13) respectively. The biological activity of some synthesized compounds was evaluated.