• 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.

• Journal of Animal Science and Technology
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• v.50 no.5
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• pp.687-694
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• 2008

This study was conducted to investigate effects of dietary supplementation of lysine and leucine on growth performance and meat quality parameters in finishing pigs. The experiment was designed using lysine levels(0.45%, 0.75%) and leucine levels(1.0%, 2.0%, 3.0%) according to 2×3 factorial design. A total of thirty-six pigs[(Landrace×Yorkshire)×Duroc] with an average initial weight of 75.5±2kg were allotted to one of the six dietary treatments. Each treatment had three replications of two pigs per replicate. No difference was found in average daily gain(P>0.05), while feed intake and feed/gain were higher in 0.45% of lysine treatments than in 0.75% of lysine treatments(P<0.05). Retail lean meat percentage was lower in 0.45% of lysine treatments than in 0.75% of lysine treatments(P<0.05), but there were no differences in other carcass characteristics(P>0.05). Marbling score was significantly increased(P<0.05) in 0.45% of lysine treatments compared to 0.75% of lysine treatments, while other meat quality parameters were not affected by lysine levels(P>0.05). Supplemental dietary leucine had no effect on growth performance, carcass characteristics, and meat quality parameters(P>0.05) except that Hunter b* value were increased with added levels of leucine(P<0.05). In conclusion, feeding of lysine-deficient diets in finishing pigs improved marbling scores of pork. Feeding diets high in leucine, however, did not increase intramuscular fat or marbling scores.

• Journal of Plant Biology
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• v.13 no.2
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• pp.11-14
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• 1970

Identification and observations of leucine aminopeptidase (LAP) and multiple molecular forms of the enzyme, isozymes, were made with a technique of starch-gel electrophoresis for various legume pollen. Plants tested other than Leguminosae demonstrated either no indication of the presence or at least tract of enzymes and the isozymes, although all legume pollen tested showed strong LAP patterns. The electrophoretic patterns of LAP failed to be shown if the extracts were heated or otherwise denatured. Extent of zymogrammatic appearance of LAP and the isozymes were characteristic of a species.

• Journal of Microbiology and Biotechnology
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• v.21 no.10
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• pp.1049-1052
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• 2011

In this study, we demonstrated the asymmetric synthesis of L-tert-leucine from trimethylpyruvate using branched-chain aminotransferase (BCAT) from Escherichia coli in the presence of L-glutamate as an amino donor. Since BCAT was severely inhibited by 2-ketoglutarate, in order to overcome this here, we developed a BCAT/aspartate aminotransferase (AspAT) and BCAT/AspAT/pyruvate decarboxylase (PDC) coupling reaction. In the BCAT/AspAT/PDC coupling reaction, 89.2 mM L-tert-leucine (ee>99%) was asymmetrically synthesized from 100 mM trimethylpyruvate.

• Journal of the Korean Society of Tobacco Science
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• v.11 no.2
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• pp.203-210
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• 1989

Leucine and isoleucine were reacted with glucose in a propylene glycol solution and volatile compounds produced from these reaction were analysed by gas chromatography and mass spectrometry. A total of 24 compounds were identified in the leucine reaction volatiles and the major components were 2-isopropyl-5-methyl-2-hexenal, methylbutyraldehyde PGA, butyraldehyde PGA, 5-methylfur-fural, isopropylmethylhexenal PGA and 2-acetylpyrrole. From the isoleucing reaction volatiles, 20 compounds were identified and the major components were methylbutyraldehyde PGA, butyraldehyde PGA and 2-acetylpyrrole. The amino acids chosen for this study were considered as giving fruity and cocoa aroma when heated with glucose.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.215-215
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• 2011

The bonding configuration and adsorption stability of alanine and leucine adsorbed on Ge(100)-2${\times}$1 surface were investigated and compared using core-level photoemission spectroscopy (CLPES) and density functional theory (DFT) calculations. The bonding configuration, stability, and adsorption energies were evaluated for two different coverage levels. In both cases, the C 1s, N 1s, and O 1s core-level spectra at a low coverage (0.30 ML) indicated that the carboxyl and amine groups participated in bonding with the Ge(100) surface in an "O-H dissociated-N dative bonded structure". At high coverage levels (0.60 ML), both this structure and an "O-H dissociation bonded structure" were present. As a result, we found that alanine adsorbs more easily (lower adsorption energy) than leucine on Ge(100) surfaces due to less steric hindrance of side chain.

• Applied Biological Chemistry
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• v.9
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• pp.59-64
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• 1968

Takju (Korean native Sake) was mashed with two different materials. One of the material was polished rice and Nuruk(mold wheat), the other one was corn and Nuruk. The amino acids in those fermenting mashes were identified by paper partition chromatography at regular intervals. The results were summarized as follows; a) Following 14 kinds of amino acids were identified in the mash of rice material; lysine, valine, proline, leucine, serine, glycine, aspartic acid, alanine, cystine, tyrosine, histidine, glutamic acid, tryptophan and phenylalanine b) Following 12 kinds of amino acids were identified in the mash of corn material; lysine, valine, proline, leucine, serine, glycine, aspartic acid, alanine, cystine, histidine, argrinine and tryptophan. c) The main amino acids in the Takju mash according to the color density of the each amino acid spot on the paper chromatograms were checked as lysine, valine, leucine, serine, proline and glycine.

• Microbiology and Biotechnology Letters
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• v.20 no.6
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• pp.677-680
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• 1992

The effects of pH, temperature and oxygen transfer rate(OTR) on L-Ieucine fermentation were investigated employing Corynebacterium glutamicum CH 1516 in 71 fermentor. The optimum pH, temperature and OTR were determined to be 7.0, $30^{\circ}C$ and 0.21 kmole $O_2$/$m^3{\cdot}hr$, respectively. For the values of OTR lower than 0.19 kmole $O_2$/$m^3{\cdot}hr$ a significant amount of lactic acid was accumulated, while the packed cell volume(PCV) was rapidly increased at higher OTR values above 0.23 kmole $O_2$/$m^3{\cdot}hr$ and glutamic acid was produced to some extent. Scale-up studies for L-Ieucine fermentation which was carried out in 12001 pilot scale fermentor reaffirmed the results of 71 fermentation. The optimum redox potential value for L-Ieucine production was found to be -150 to -170 mY.

• Journal of the Korean Chemical Society
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• v.41 no.6
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• pp.304-312
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• 1997

Acetolactate synthase(ALS) is the common enzyme in the biosynthetic of valine, leucine, and isoleucine, and is the target of several classes of structually unrelated herbicides, including sulfonylureas, imidazolinones, and triazolopyrimidines. In an effort to develop new and desirable herbicides, we have synthesized 4,6-dimethoxypyrimidine derivatives, and examined their inhibitory activities on pea ALS. The most active compound was found to be K11570 and $IC_{50}$ value for K11570 was 0.2 ${\mu}M.$ The inhibition of pea ALS by K11570 was biphasic, showing increased inhibition with incubation time. The K11570 showed mixed-type inhibition with respect to substrate pyruvate. Dual inhibition analysis of K11570 versus sufonylurea herbicide Ally and feedback inhibitor leucine revealed that three inhibitors were competitive for binding to ALS. The arginine modified enzyme showed decreased inhibition by K11570, sufonylurea Ally, and leucine, in constrast to, tryptophan modification did not affect on the sensitivity of ALS to the inhibitors.

• YAKHAK HOEJI
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• v.38 no.5
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• pp.530-543
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• 1994

To study the feasibility of transmucosal delivery of leucine enkephalin (Leu-Enk) and $[D-ala^2]$-leucine enkephalinamide (YAGFL), their degradation extents and pathways in various rabbit mucosa extracts were investigated by high performance liquid chromatography. The degradation of Leu-Enk and YAGFL was observed to follow the first-order kinetics. The degradation half-lives of Leu-Enk in the nasal, rectal and vaginal mucosal extracts were 1.62, 0.37 and 1.12 hrs and those of YAGFL were 30.55, 9.70 and 6.82 hrs, respectively, indicating Leu-Enk was degraded in a more extensive and rapid manner than YAGFL. But the mucosal and serosal extracts of the same mucosa showed the similar degradation rates for both pentapeptides. The degradation was most rapid in the neutral pH and increasing concentrations of substrates retarded the degradation rates. The maior hydrolytic fragments of Leu-Enk were Des-Tyr-Leu-Enk and tyrosine, indicating the enzymatic hydrolysis by aminopeptidases. However, the data also suggested endopeptidases such as dipeptidyl carboxypeptidase and dipeptidyl aminopeptidase could play some role in the degradation of Leu-Enk. On the other hand, the hydrolytic fragments of YAGFL in all the mucosa extracts were mainly Tyr-D-Ala-Gly and Phe-Leu-Amide, demonstrating the hydrolytic breakdown by endopeptidases. The degradation pathways were further explored by concomitantly determining the formation of smaller metabolites of primary hydrolytic fragments of Leu-Enk and YAGFL in the mucosa extracts.