• BMB Reports
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• 제30권5호
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• pp.332-336
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• 1997

The stimulatory effects of leucine on the activities of two soluble forms of brain glutamate dehydrogenase isoproteins (GDH I and GDH II) have been studied at various conditions. There were significant differences between GDH I and GDH II in their sensitivities to the action of leucine. When the effects of varied leucine concentrations on GDH activities were studied in the direction of reductive amination of 2-oxoglutarate with NADPH as a coenzyme, a marked activation was observed for both isoproteins at leucine concentrations up to 10 mM, whereas both isoproteins showed activation to a lesser extent with NADH as a coenzyme. The stimulatory effects of leucine on GDH activities in the direction of the oxidative deamination of glutamate were also observed, but to a much lesser extent. Leucine relieved the inhibition of GDH I by GTP and this resulted in an increase in the apparent activation by leucine in the presence of GTP. 2-Oxoglutarate was found to give rise to high substrate inhibition and leucine significantly reduced the substrate inhibition in the presence of $200\;{\mu}M$ NADH. Thus, the effects of leucine might be composed of a direct effect on the enzyme together with a relief of high substrate inhibition.

• Journal of Microbiology
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• 제44권1호
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• pp.50-53
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• 2006

Cys-29 and Cys-251 of Streptomyces albus valine dehydrogenase(ValDH) were highly conserved in the corresponding region of $NAD(P)^+$-dependent amino acid dehydroganase sequences. To ascertain the functional role of these cysteine residues in S. albus ValDH, site-directed mutagenesis was performed to change each of the two residues to serine. Kinetic analyses of the enzymes mutated at Cys-29 and Cys-251 revealed that these residues are involved in catalysis. We also constructed mutant ValDH by substituting valine for leucine at 305 by site-directed mutagenesis. This residue was chosen, because it has been proposed to be important for substrate discrimination by phenylalanine dehydrogenase (PheDH) and leucine dehydrogenase (LeuDH). Kinetic analysis of the V305L mutant enzyme revealed that it is involved in the substrate binding site. However it displayed less activity than the wild type enzyme toward all aliphatic and aromatic amino acids tested.

• 한국작물학회지
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• 제30권4호
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• pp.405-411
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• 1985

본 실험은 보리품종의 구분에 가장 적합한 전기영동법과 효소를 구명하고자 6개 보리품종(알찬보리, 수원 216호, 조풍보리, 사천 6호, 향맥, 히노데하다가)의 종실 단백질을 7.5％ polyacrylamide slab gel, 2-30％ polyacrylamide porosity gradient tube gel, isoelectricfocusing(pH 4-9)과 starch gel을 사용 전기영동 후 protein band pattern과 esterase, acid phosphatase, malate dehydrogenase, glutamate dehydrogenase 및 leucine aminopeptidase의 동위효소 pattern을 관찰하였던 결과는 다음과 같았다. 1. 7.5％ polyacrylamide slab gel에서 단백질 pattern과 2-30％ polyacrylamide porosity gradient tube gel에서의 단백질과 esterase의 band pattern이 품종간 뚜렷한 차이를 보여 보리품종구분에 가장 적합하였다. 2. Acid phosphatase, malate dehydrogenase, glutamate dehydrogenase 및 leucine aminopeptidase 등의 동위효소 pattern은 모든 실험한 품종이 동일한 형태를 보여 품종구분에 이용하기에는 적합하지 않았다.

• Molecules and Cells
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• 제45권7호
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• pp.495-501
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• 2022

Leucine dehydrogenase (LDH, EC 1.4.1.9) catalyzes the reversible deamination of branched-chain L-amino acids to their corresponding keto acids using NAD⁺ as a cofactor. LDH generally adopts an octameric structure with D4 symmetry, generating a molecular mass of approximately 400 kDa. Here, the crystal structure of the LDH from Pseudomonas aeruginosa (Pa-LDH) was determined at 2.5 Å resolution. Interestingly, the crystal structure shows that the enzyme exists as a dimer with C2 symmetry in a crystal lattice. The dimeric structure was also observed in solution using multiangle light scattering coupled with size-exclusion chromatography. The enzyme assay revealed that the specific activity was maximal at 60℃ and pH 8.5. The kinetic parameters for three different amino acid and the cofactor (NAD⁺) were determined. The crystal structure represents that the subunit has more compact structure than homologs' structure. In addition, the crystal structure along with sequence alignments indicates a set of non-conserved arginine residues which are important in stability. Subsequent mutation analysis for those residues revealed that the enzyme activity reduced to one third of the wild type. These results provide structural and biochemical insights for its future studies on its application for industrial purposes.

• 한국균학회지
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• 제17권1호
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• pp.35-38
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• 1989

팽나무버섯 균사체 DNA를 대장균 프라스미드인 PBR322를 이용하여 gene library를 작성 하였다. 팽나무버섯에서 ${\beta}-isopropyl$ malate dehydrogenase 유전자 클론을 얻었으며 이 클론은 대장균 Leucine 요구성 균주를 complementation 시켰다. 이 클론의 팽나무버섯 DNA 크기는 약 lKb였으며 BamH1과 Ava 1 제한효소 절단부위를 지니고 있었다.

• 한국균학회지
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• 제17권1호
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• pp.27-30
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• 1989

팽나무버섯 ${\beta}-isopropylmalate$ dehydrogenase의 유전자가 PBR322에 크로닝된 백터를 이용하여 사철느타리버섯 Leucine 영양요구성 균주를 형질전환 시켰다. 형질전환율은 저조하였으나 형질전환된 균총은 버섯 최소배지에서 다소 느리지만 생육할 수 있었다. 형질전환은 Southern hybridization과 형질 전환된 사철 느타리버섯 염색체 DNA를 다시 대장균에 형질전환시켜 확인하였다.

• Nutrition Research and Practice
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• 제11권2호
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• pp.121-129
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• 2017

BACKGROUND/OBJECTIVES: The study was conducted to evaluate the effects of dietary leucine supplementation on mitochondrial biogenesis and energy metabolism in the liver of normal birth weight (NBW) and intrauterine growth-retarded (IUGR) weanling piglets. MATERIALS/METHODS: A total of sixteen pairs of NBW and IUGR piglets from sixteen sows were selected according to their birth weight. At postnatal day 14, all piglets were weaned and fed either a control diet or a leucine-supplemented diet for 21 d. Thereafter, a $2{\times}2$ factorial experimental design was used. Each treatment consisted of eight replications with one piglet per replication. RESULTS: Compared with NBW piglets, IUGR piglets had a decreased (P < 0.05) hepatic adenosine triphosphate (ATP) content. Also, IUGR piglets exhibited reductions (P < 0.05) in the activities of hepatic mitochondrial pyruvate dehydrogenase (PDH), citrate synthase (CS), ${\alpha}$-ketoglutarate dehydrogenase (${\alpha}$-KGDH), malate dehydrogenase (MDH), and complexes I and V, along with decreases (P < 0.05) in the concentration of mitochondrial DNA (mtDNA) and the protein expression of hepatic peroxisome proliferator-activated receptor-${\gamma}$ coactivator $1{\alpha}$ (PGC-$1{\alpha}$). Dietary leucine supplementation increased (P < 0.05) the content of ATP, and the activities of CS, ${\alpha}$-KGDH, MDH, and complex V in the liver of piglets. Furthermore, compared to those fed a control diet, piglets given a leucine-supplemented diet exhibited increases (P < 0.05) in the mtDNA content and in the mRNA expressions of sirtuin 1, PGC-$1{\alpha}$, nuclear respiratory factor 1, mitochondrial transcription factor A, and ATP synthase, $H^+$ transporting, mitochondrial F1 complex, ${\beta}$ polypeptide in liver. CONCLUSIONS: Dietary leucine supplementation may exert beneficial effects on mitochondrial biogenesis and energy metabolism in NBW and IUGR weanling piglets.

• 동의생리병리학회지
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• 제26권1호
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• pp.53-58
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• 2012

The aim of this study was to investigate the antimicrobial, antiperspirant and deodorant effect of herb mixtures including Schisandra chinensis(SC). This herb mixtures including Schisandra chinensis was made of Astragalus membranaceus(AM), Triticum aestivum(TA), Atractylodes japonica(AJ) and peppermint essential oil extracted from Mentha piperita(MP). We examined antimicrobial activity, antiperspirant activity and L-leucine dehydrogenase activity of the herbal extracts. We found that the mixture of SC and MP have the best antimicrobial effects on B. subtilis subsp. spizizenii and mixture of SC, AJ, AM and TA have best antiperspirant effect. Moreover, the combination of SC and AM showed the most inhibitory effect on L-leucine dehydrogenase activity. These results suggested that the herb mixtures Including Schisandra chinensis have good antimicrobial and antiperspirant effects.

• Parasites, Hosts and Diseases
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• 제33권4호
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• pp.331-340
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• 1995

형태적으로 Aconthamoeba polyphaga로 동정긴 일곱 분리주의 동위효소 profile과 Mitochondria (Mt) DNAangerprint를 비교 분석하였다. 8가지 제한효소(B91 II. Sca I, Cla I, EcoR I, Xba I, Kpa I, Sal I. 및 Sst I)에 의한 Mt DNA fhlgerprint는 주간의 심한 다양성을 나타내었다. B가지 동위효소 (acid phosphatase, lactate dehydrogenase 및 glucose-6-phosphate dehydrogenase)는 주간의 심한 다양성을 나타내었으나 다른 3가지 동위효소(glucose phosphate isomerase, leucine aminopeptidase 및 malatedehydrogenase)는 비슷한 양상으로 나타났다 Ap 주의 동위효소 양상과 Mt DNA fmgerprint는 Jones 주와 동일하였다. Mt DNA fingerprinting은 대식가시아메바 주의 동정과 분리에 매우 유용함을 알았다. Aconthamoeba polvphasa의 우리말 학명을 대식가시아메바로 제안한다.

• Journal of Nutrition and Health
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• 제42권8호
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• pp.714-722
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• 2009

The principal objective of this study was to determine the effects of leucine on body weight reduction in high fat diet-induced overweight rats. To induce overweight, six-month-old male Sprague-Dawley rats (n = 80) were divided into 8 groups; one group of 10 rats was fed on a normal fat diet and the remaining 70 rats were fed on a high-fat diet (40% of energy as fat) for 14 weeks. Then, 10 rats fed on the normal fat diet and another 10 rats fed on the high fat diet were sacrificed to identify overweight induction. The remaining 60 rats were divided randomly into 6 groups according to body weight and fed on one of the diets with different dietary fat levels (9.6% or 40% of energy as fat) and leucine levels (0, 0.6 or 1.2 g/kg BW) for the following 5 weeks of experiments. The body weight loss in the Leu-administered groups (0.6 g, 1.2 g/kg BW) was significantly higher than those of Leu non-administered groups. The perirenal fat pad weights in the Leu-administered groups were significantly lower than those of the Leu non-administered groups. Of the hepatic enzymes, glucose-6-phosphate dehydrogenase (G6PDH) activities were reduced significantly in the Leu-administered groups than in the Leu non-administered groups. With the oral glucose tolerance test (OGTT), the incremental areas under the curve of the glucose response (IAUC) of the Leu-administered groups were significantly lower than those of the Leu non-administered groups. The fasting glucose concentration and HOMA-IR of the Leu-administered groups were significantly lower than those of the Leu non-administered groups. In conclusion, the results of this study suggest that one of the possible mechanisms of leucine in the observed body weight reduction might involve the inhibition of lipogenic enzyme activities such as glucose-6-phosphate dehydrogenase, rather than the activation of lipolysis enzymes. Additionally, leucine adminstration resulted in improved glucose metabolism.