• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.40 no.5
• /
• pp.637-643
• /
• 1995

TR75, a rice (Oryza sativa L. var. Sasanishikj) mutant resistant to 5-methyltryptophan (5MT) was segregated from the progenies of its initial mutant line, TR1. The 5MT resistance of TR75 was inherited in the M$_{8}$ generations as a single dominant nuclear gene, and was also expressed in callus derived from seeds, roots, and anthers as well as in the seedlings. The callus induced from these organs could grow at 50 mg/1 of 5MT, whereas the growth of wild-type callus was completely inhibited even at 25 mg/1. The seedlings of TR75 did not show resistance to L-azetidine-2-carboxylic acid, S-2-aminoethyl-L-cysteine, p-fluoro-DL-phenylalanine. The content of free amino acids in the TR75 homozygous seeds increased approximately 1.5 to 2.0 fold compared to wild-type seeds. Especially, the contents of tryptophan, phenylalanine and aspartic acid were 5.0, 5.3 and 2.7 times higher than those of wild-type seeds, respectively.y.

• Analytical Science and Technology
• /
• v.19 no.1
• /
• pp.107-114
• /
• 2006

Early diagnosis and medical intervention are critical for the treatment of patients with metabolic disorders. A rapid analytical method was developed for simultaneous quantification of organic acids and amino acids in urine without labor-intensive pre-extraction procedure showing high sensitivity and specificity. A new method consisted of simple two-step trimethylsilyl (TMS)-trifluoroacetyl (TFA) derivatization using GC/MS-selective ion monitoring (SIM). Filter paper urine specimens were dried under nitrogen after being fortified with internal standard (tropate) in a mixture of distilled water and methanol. Methyl orange was added to the residue as indicator reagent. Silyl derivative of carboxylic functional group was followed by trifluoroacetyl derivative for amino functional group. N-methyl-N-(trimethylsilyl-trifluoroacetamide) and N-methyl-bistrifluoroacetamide were consecutively added and heated for 15-20 min at $65^{\circ}C-70^{\circ}C$, for TMS-TFA derivative, respectively. This reactant was analyzed by GC/MS-SIM. Linear dynamic range showed 0.001-50 mg with the detection limit of (S/N=3) 10-200 ng, and the quantification limit of 80-900 ng in urine. Correlation coefficient of regression line was 0.994-0.998. When the method was applied to the patients 'urine, it clearly differentiated the normal from the patient with metabolic disorder. The study showed that the developed method could be the method of choices in rapid and sensitive screening for organic aciduria and amino acidopathy.

• Proceedings of the Korean Society for Applied Microbiology Conference
• /
• 1986.12a
• /
• pp.524.3-524
• /
• 1986

Carboxymethyl cellulase (CMCase) produced by cloned B. megaterium was found to contain 5.2% carbohydrate but no metal ion. The enzyme was isoelectric at pH 7.23 and was high is basic amino acids. The N-terminal of the enzyme was glutamic acid. The cellulolytic activity of this enzyme was extended to the small molecular substrates such as from cellotriose to cellopentaose. In additon, the enzyme showed transglycoslation activity. The pK values of the enzyme we estimated to be 4.4 and 6.7, andthat of the enzyme-substrate complex were 4.2 and 7.2, respectively. The enzyme was not affected by the treatment with iodoacetic acid, but the modification of enzyme with carbodiimide and diethyl pyrocarbonate resulted in a marked loss of the enzyme activity. These results suggest that the active site of enzyme essentially contains carboxylic and imidazole group of amino acid residues.

• Archives of Pharmacal Research
• /
• v.21 no.2
• /
• pp.168-173
• /
• 1998

The epoxyalkanoyl derivatives were designed and synthesized as ACE inhibitors. Coupling of unsaturated carboxylic acids with amino acids and following epoxidation with dimethyldioxirane gave the epoxyalkanoyls with high yield. The inhibitory activity of synthesized compounds on angiotensin converting enzyme was $IC_{50}$ values of 0.06~5.5 ${\mu}M$.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.37 no.5
• /
• pp.555-560
• /
• 2008

Amino acid transporters are essential for the growth and proliferation in all living cells. Among the amino acid transporters, the system L amino acid transporters are the major nutrient transport system responsible for the $Na^+$-independent transport of neutral amino acids including several essential amino acids. The L-type amino acid transporter 1 (LAT1), an isoform of system L amino acid transporter, is highly expressed in cancer cells to support their continuous growth and proliferation. 2-Aminobicyclo-(2,2,1)-heptane-2-carboxylic acid (BCH) is a model compound for the study of amino acid transporter as a system L selective inhibitor. We have examined the effect and mechanism of BCH on cell growth suppression in HEp2 human head and neck squamous cell carcinoma. The BCH inhibited the L-leucine transport in a concentration-dependent manner with a $IC_{50}$ value of $51.2{\pm}3.8{\mu}M$ in HEp2 cells. The growth of HEp2 cells was inhibited by BCH in the timeand concentration-dependent manners. The formation of DNA ladder was not observed with BCH treatment in the cells. Furthermore, the proteolytic processing of caspase-3 and caspase-7 in the cells were not detected by BCH treatment. These results suggest that the BCH inhibits the growth of HEp2 human head and neck squamous cell carcinoma through the intracellular depletion of neutral amino acids for cell growth without apoptotic processing.

• Proceedings of the Korean Society for Applied Microbiology Conference
• /
• 1986.12a
• /
• pp.505.2-506
• /
• 1986

L-Azetidine-2-carboxylic acid (A-2-C), a four-membered cyclic imino acid has been identified in certain plants, and the microorganism Actinoplanes ferrugineus. The imino acid A-2-C has a physiological significance as an antgaonist of proline during peptide synthesis. The biosynthetic mechanism for the formation of A-2-C has not been studied in any detail. By using various amino acids such as methionine and S-adenosyl-L-methionine labeled with deuterium or carbon-14, the details of the biosynthetic pathway and a possible mechanism for the formation of L-A-2-C in .4. ferrugineus have been unravelled, Both in vivo and in vitro experimental results suggest the biosynthesis of L-A-2-C is mediated by a confactor containing a carbonyl group, probably pyridoxal Phosphate. S-Adenosyl-L-methionine, which seems to be the direct biosynthetic substrate, has undergone a f-displacement by an ${\alpha}$-amino group of the amino acid portion of the substrate S-adenosyl-L-methionine potentially via a vinylglycine intermediate. The overall stereochemical events at the ${\beta}$-carbon of the substrate have been shown to inversion of configuration. The overall stereochemical events at the -position of the sub- strate have also been shown to occur with inversion of configuration. The ${\beta}$, ${\gamma}$-elimination reaction of the substrate seems to follow a cisoidal-type mechanism and the addition portion of the reaction a transoidal-type mechanism . The assignment of the proton NMR of A-2-C has been deduced by apply- ing NOE difference experiments, Gd(III) line-broadening experiments and 2D-NOESY experiments of regio-and stereospecificially deuterated A-2-C's.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.32 no.5
• /
• pp.758-763
• /
• 2003

Amino acid transporters play an important role in supplying nutrients to normal and cancer cells for cell proliferation. System L is a major transport system responsible for the N $a^{＋}$-independent, large neutral amino acids including several essential amino acids. L-type amino acid transporter 1 (LAT1), an isoform of system L amino acid transporter, is highly expressed presumably to support their continuous growth and proliferation in malignant tumors. 2-Aminobicyclo- (2,2,1) -heptane-2-carboxylic acid (BCH) is a model compound for study of amino acid transporter as a system L selective inhibitor. In the present study, we examined whether BCH induced growth inhibition in KB human oral squamous carcinoma cell line or not. The uptake of L-［$^{14}$ C］leucine by KB cells is inhibited by BCH in a concentration dependent manner with a Ι $C_{50}$ value of 75.3$\pm$6.2 ${\mu}{\textrm}{m}$ and a $K_{i}$ value of 98.7$\pm$ 4.1 ${\mu}{\textrm}{m}$. The growth of KB cells is inhibited by BCH in time dependent manner and concentration dependent manner with a Ι $C_{50}$ value of 11.1 $\pm$0.8 mM. In the DNA of KB cells treated with the various concentrations and various periods of BCH, the characteristic ladders associated with DNA fragmentation were not observed. These results suggest that BCH inhibits the growth of KB oral epidermoid carcinoma cells through the inhibition of transport of neutral amino acids into cells without DNA break down. This phenomenon will be a new rationale for anti-cancer therapy.y.

• Proceedings of the Korean Society of Plant Pathology Conference
• /
• 2003.10a
• /
• pp.109.1-109
• /
• 2003

From the PMMV (pepper mild mottle virus)-inducible ESTs differentially expressed in Capsicum chinense PI257284, we isolated a full-length cDNA (CcPHZF： Capsicum chinense phenazine), encoding a phenazine biosynthesis protein which catalyzes the hydroxylation of phenozine-1-carboxylic acid to 2-hydroxyphenazine-1-carboxylic acid. Phenazine compound has been known to exhibit broad-spectrum of antibiotic activity against various species of bacteria and fungus. The entire region of CcPHZF is 879 bp in length and the open reading frame predicted a polypeptide of 292 amino acids. The homolog of CcPHZF is not Present in database except clones of AC004044 and NM100203 from Arabidopsis with 58 and 59％, respectively. Genomic Southern analysis indicated that the pepper genome contains a single copy of CcPHZF. The CcPHZF was strongly induced in the pepper leaves 3 days after PMMV treatment, when HR occurs on the leaf surface. Characterization of CcPHZF is underway to investigate if the CcPHZF is related to disease resistance against pathogens.

• Horticultural Science & Technology
• /
• v.32 no.2
• /
• pp.261-268
• /
• 2014

Senescence of Hosta ventricosa flowers was firstly characterized as ethylene-sensitive since the deterioration of the tepal was accompanied by increased endogenous ethylene biosynthesis. The full-length cDNAs and DNAs of 1-aminocyclopropane-1-carboxylic acid (ACC) synthase (ACS) and ACC oxidase (ACO) involved in ethylene biosynthesis were cloned from H. ventricosa flowers. The HvACS ORF with 1347 bp and two introns, encoded a polypeptide of 448 amino acids showing 79% homology with that in Musa acuminata. The HvACO ORF contained 957 bp and three introns, encoding a 318-residue polypeptide showing 83% homology with that in Narcissus tazetta. The timing of the induction of HvACS expression was in correspond to the timing of the increase in ethylene production, and that the up-regulation of HvACO transcript was closely correlated with an elevated ethylene production, but underwent a down-regulation in wounded leaves with elevated ethylene emission. The results, together with expression analysis in vegetative tissues, suggested that both HvACS and HvACO were specifically regulated by flower senescence.

• Molecules and Cells
• /
• v.19 no.2
• /
• pp.228-231
• /
• 2005

Recent characterization of several genes involved in plant defense responses suggested that ubiquitin-mediated protein degradation has a role in these responses. We isolated two cDNAs (NtUBA1 and NtUBA2) encoding ubiquitin-activating enzyme (E1) from Nicotiana tabacum cv. BY-2. The open reading frames of both encoded 1080 amino acids, corresponding to molecular masses of 120 kDa. The E1s and corresponding transcripts were upregulated by infection with tobacco mosaic virus (TMV) and tomato mosaic virus (ToMV), and to a lesser extent by cucumber mosaic virus (CMV). Furthermore, they were also upregulated by wounding stress, and the plant hormones salicylic acid, jasmonic acid and the ethylene precursor, aminocyclopropane-1-carboxylic acid (ACC). Our findings support the idea that the ubiquitin-proteasome system plays a role in plant disease defenses.