• The Korean Journal of Zoology
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• v.22 no.1
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• pp.19-25
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• 1979

To determine the metabolism of leucine during the cuticle formation and the sclerotization process in Pieris rapae L., $U-^3$H-leucine or $U-^4$C-tyrosine is injected into the haemolymph of newly molted pupa through dorsal cuticle of heart area. The results show that leucine as a common amino acid participates in the synthesis of cuticle protein over the first 3 hr after ecdysis. It is also shown that leucine in the haemolymph at ecdysis is freely being moved between major internal organs during the short time period post-ecdysis, providing the evidence for some involvements including haemolymph protein synthesis and storage of fat body and gut in metabolism of leucine.

• Korean Journal of Microbiology
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• v.28 no.4
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• pp.318-323
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• 1990

The bacterial secondary production was measured at 6 sites of Lake Soyang in October, 1989 by $^{3}$H-thymidine incorporation rate. Verfication for the method of bacterial secondary production measurement showed that $^{3}$H-thymidine incorporated into DNA, RNA and protein by average percentage of 38.45, 42.27 and 20.07%, respectively. THe more increased incoporated $^{3}$H-thymidine, the more increasde DNA fraction, but protein fraction was generally low. Incorporation of rate of /usp 3/H-thymidine. $^{3}$H-leucine into protein correlated with protein fraction of incorporated $^{3}$H-thymidine. Conversion factors were calculated as follows; $1.83*10 ^{20}$ cells/moles of thymidine incorporated/hr and 1.69*10$^{22}$ cells/moles of leucine incorporated/hr.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1978.04a
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• pp.96.3-96
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• 1978

Biotin 요구성 glutamic acid 생산능을 가진 Br-evibacterium sp.의 isoleucine 영양요구성 변이주가 다량의 L-leucine을 생성함을 발견하였다. 본균주에 관한 탄소원, 질소원, 무기염, vitamin, amino acid 등의 영양물질과 온도, 공기주입량, pH등에 관한 실험으로 다음과 같은 결과를 얻었다. 본균주는 탄소원, 질소원으로서 10% glucose와 4% $(NH_4)_2SO_4를$ 공합하여 $30^{\circ}C,$ 88시간 배양시킨 결과, 액중에 21 mg/ml의 L-leucine이 축적되었다. Fe$^{2+}$와 $Mn^{2+}$의 동시첨가는 L-leucine생성에 효과적이었으며 thiamine 역시 L-leucine 생성에 효과적이었다. 30ι jar fermentor 에서 폐당밀을 주원료로 한 실험결과, 폐당밀, $(NH_4)/SO_4,$ $KH_2PO_4,$ $MgSO_4ㆍ7H_2O로$ 구성된 액체배지에서 $30^{\circ}C,$ 36시간 배양시킨 것이, 27mg/ml의 L-leucine이 축적되었으며 이때의 대당수율은 16%이었다.

• 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 Microbiology and Biotechnology
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• v.17 no.10
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• pp.1682-1687
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• 2007

The differences in the nonvolatile metabolites of pine-mushrooms (Tricholoma matsutake Sing.) according to different parts and heating times were analyzed by applying principal component analysis (PCA) to $^1H$ nuclear magnetic resonance (NMR) spectroscopy data. The $^1H$ NMR spectra and PCA enabled the differences of nonvolatile metabolites among mushroom samples to be clearly observed. The two parts of mushrooms could be easily discriminated based on PC 1, and could be separated according to different heattreated times based on PC 3. The major peaks in the $^1H$ NMR spectra that contributed to differences among mushroom samples were assigned to trehalose, succinic acid, choline, leucine/isoleucine, and alanine. The content of trehalose was higher in the pileus than in the stipe of all mushroom samples, whereas succinic acid, choline, and leucine/isoleucine were the main components in the stipe. Heating resulted in significant losses of alanine and leucine/isoleucine, whereas succinic acid, choline, and trehalose were the most abundant components in mushrooms heat-treated for 3 min and 5 min, respectively.

• Macromolecular Research
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• v.12 no.3
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• pp.258-262
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• 2004

We have developed facile and rapid polycondensation reactions of N-trimellitylimido-L-leucine diacid chloride 1 with eight different derivatives of hydantoin compounds 2a-h, in the presence of a small amount of a polar organic medium, such as Ο-cresol, by using a domestic microwave oven. The polycondensation reactions proceeded rapidly-they were complete within 7-9 min-to produce a series of novel optically active poly(amide-imide)s (3a-h) in high yield with inherent viscosities of 0.33-0.51 dL/g. We characterized the resulting poly(amide-imide)s by elemental analysis, thermal gravimetric analysis (DSC, TGA, and DTG), and FTIR spectroscopy, and by measuring their viscosities, specific rotations, and solubilities. All of the polymers were soluble at room temperature in polar solvents such as N ,N-dimethylacetamide, N,N-dimethylformamide, dimethylsulfoxide, tetrahydrofuran, and N-methyl-2-pyrrolidone.

• Korean Journal of Poultry Science
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• v.31 no.3
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• pp.137-143
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• 2004

The fractional synthesis rates(FSR) were measured with 2l-wk and 3l-wk-old broiler breeder pullets and hens to investigate the effect of sexual maturity on FSR. The FSR were obtained from chicken tissues and blood samples using High-Performance Liquid Chromatography/Mass Spectrometry(HPLC/MS). A L-l-13C, 15N -leucine saline solution was infused by bolus injection as a tracer into broiler breeder pullets in the experiment. A rapid HPLC/MS method was developed to measure the isotopic enrichments of leucine in plasma, tissue samples, and eggs. The enrichments of stable isotope leucine incorporated into protein and the enrichments of the stable isotope free leucine were measured in liver, breast muscle and blood samples. Two sets of experiments were conducted. In experiment one, 2l-wk-old, sexually immature broiler breeder pullets were divided into groups of three and blood samples were collected at 20 or 30 min intervals until 1.5 h from initial injection. The pullets were sacrificed in groups of three at varying time intervals for 7 h after injection. The liver, breast muscle and blood samples were removed for analysis. The FSR were estimated to be 8.7l%/day for liver, 4.06％/day for breast muscle, and 5.08％/day for blood samples in 30 minutes after injection from the enrichment ratios. In experiment two, sexually matured 3l-wk-old broiler breeder hens were assorted into groups of three and blood samples were obtained at 20 or 30 min intervals for 2 h. The FSR for blood samples were determined. The broiler breeder hens were sacrificed in groups of three at various time intervals until 7 h after injection and liver, breast muscle and blood samples were removed for analysis. The FSR were calculated to be 5.96％/day for liver. Eggs were collected from five chickens daily for 10 days after large bolus injection. The average of total enrichments of stable isotope in egg albumin was increased by 0.064% at 4 days after injection and was back to normal in 7 days.

• Nutritional Sciences
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• v.3 no.2
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• pp.57-65
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• 2000

Partial enteral nutrition (PEN) supplemented with insulin-like growth factor-I (IGF-I) to neonatal piglets receiving parenteral nutrition increases lactase-phlorizin hydrolase (LPH) activity, but not LPH mRNA. The goal of the current study was to investigate the mechanism by which IGF-I up-regulates LPH activity. We hypothesized that IGF-I regulates LPH synthesis post-transcriptionally. Methods: Newborn piglets (n=15) received 100% parenteral nutrition (TPN), 80% parenteral nutrition + 20% PEN (PEN), or PEN + IGF-I (1.0mg/kg/d). On day 7, two stable isotopes of leucine, [$^2 H_3$]-leucine and [$^{13}C_1$]-L-leucine were intravenously administered to measure mucosal protein and brush LPH (BB LPH) synthesis. Results: Weight gain, nutrient intake and jejunal weight and length were similar among the treatment groups. PEN increased mucosal weight, villus width and cross-sectional area, LPH activity, mRNA expression and the abundance of proLPHh compared to 100% TPN (p<0.05). IGF-I further increased mucosal weight, LPH activity and LPH activity per unit BB LPH ~2-fold over PEN alone (p<0.05), but did not affect LPH mRNA or the abundance of proLPHh or mature LPH. Isotopic enrichment of [$^2 H_3$]-leucine and [$^{13}C_1$]-L-leucine in plasma, mucosal protein and LPH precursors, and the fractional and absolute synthesis rates of mucosal protein and LPH were similar among the treatment groups. Total mucosal protein synthesis was increased 60% (p<0.05) and LPH synthesis tended (p=0.14) to be greater in the IGF-I treated animals compared to the other two groups. Conclusions: The primary mechanism by which IGF-I up-regulates LPH may be post-translational, either via reducing LPH turnover, or by specifically altering LPH activity.

• Bulletin of the Korean Chemical Society
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• v.7 no.3
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• pp.213-217
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• 1986

A series of copolypeptides of glutamic acid and leucine have been synthesized by N-carboxy-${\alpha}$-amino acid anhydride procedure and cast to form injectable microparticulate monolithic devices in which indomethacin was physically dispersed. With these devices, various release properties and possible clinical application were studied. The release rate of the drug had a close relationship with the monomer composition of the copolymer matrix as well as the environmental pH condition. The monolithic device of glutamic acid/leucine = 50/50 was found to be the most promising one as a ploymeric delivery system of indomethacin. The intrinsic viscosity of this copolymer was 4.35 dl/g and the release rate was 18.5${\mu}g/g/day$.

• BMB Reports
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• v.37 no.3
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• pp.320-334
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• 2004

StMBF1 (Solanum tuberosum multiprotein bridging factor 1) is a plant member of the MBF1 family of transcriptional co-activators. In an attempt to understand the role of StMBF1, we analyzed its interaction with plant transcription factors of the homeodomain-leucine zipper (Hd-Zip) family, a group of proteins with a typical leucine zipper motif adjacent to a homeodomain. StMBF1 is able to interact in vitro with the Hd-Zip protein Hahb-4 both in the presence and absence of DNA. Upon binding, StMBF1 increases the DNA binding affinity of Hahb-4, and of another plant homeodomain containing protein from the GL2/Hd-Zip IV family, HAHR-1. The biological role of interactions is discussed in this paper.