• BMB Reports
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• 제50권8호
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• pp.401-410
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• 2017

The protein disulfide isomerase (PDI) family is a group of multifunctional endoplasmic reticulum (ER) enzymes that mediate the formation of disulfide bonds, catalyze the cysteine-based redox reactions and assist the quality control of client proteins. Recent structural and functional studies have demonstrated that PDI members not only play an essential role in the proteostasis in the ER but also exert diverse effects in numerous human disorders including cancer and neurodegenerative diseases. Increasing evidence suggests that PDI is actively involved in the proliferation, survival, and metastasis of several types of cancer cells. Although the molecular mechanism by which PDI contributes to tumorigenesis and metastasis remains to be understood, PDI is now emerging as a new therapeutic target for cancer treatment. In fact, several attempts have been made to develop PDI inhibitors as anti-cancer drugs. In this review, we discuss the properties and diverse functions of human PDI proteins and focus on recent findings regarding their roles in the state of diseases including cancer and neurodegeneration.

• 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.

• BMB Reports
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• 제32권5호
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• pp.419-428
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• 1999

Tumor necrosis factor (TNF) receptor members have unique structures composed of 2-4 cysteine - rich pseudorepeats in the extracellular domain. On ligation by trimeric ligand molecules, oligomerization of three receptor molecules occurs, which in turn activates the receptor and recruits intracellular signaling molecules to the cytoplasmic tail to initiate biological events. Recently, the numbers of tumor necrosis factor receptor and ligand family members have been rapidly expanding. Functional characterization of the new members has indicated redundant roles with other known members as well as provided insights into novel functions. In particular, identification of soluble decoy receptors which have the ability to bind multiple ligands highlights a complex control mechanism of immune responses by these molecules. Studies of the new members have also revealed that the TNF receptor and ligand family members play an important role in other than the immune system.

• Bulletin of the Korean Chemical Society
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• 제21권4호
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• pp.379-382
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• 2000

The temperature dependence of the kinetic parameters of the aspartase-catalyzed reaction has been examined in the direction of deamination. The pK1values at 37$^{\circ}C$, 25$^{\circ}C$, 16$^{\circ}C$ and 7$^{\circ}C$ were 6.2 $\pm$ 0.1, 6.3 $\pm$ 0.1, $6.7{\pm}0.3$ and 6.9 $\pm$ 0.3, respectively. On the other hand, the pK2 values at 37$^{\circ}C$,25$^{\circ}C$, 16$^{\circ}C$ and 7$^{\circ}C$ were 8.1 $\pm0.2$, 8.3 $\pm$ 0.2, 8.2 $\pm$ 0.3 and 8.0 $\pm$ 0.2,respectively. The enthalpy of ionization, DHion, calculated from the slope of pK1, are 6.0 $\pm$ 0.3 kcal/mol. These results validate the prediction that aspartase requires a histidine residue for a general base, and a cysteine (or having a carboxyl functional group) for a general acid.

• 한국환경성돌연변이발암원학회지
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• 제16권1호
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• pp.13-18
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• 1996

One mechanism of free-radical production by ethanol is suggested to be through the intracellular conversion of XDH to XO by increased ratio of NADH to NAD. The major mechanism for physiological compensation of cytosolic NADH/NAD balance is the malate/aspartate shutfie. Therefore, it is important to develop the method to improve the efficiency of malate/aspartate shuttle in ethanol metabolism. In the present study, various amino acids and organic acid involved in the shuttle were tested for their functional efficiency in modulating shuttle in the ethanol-perfused rat liver. The rate of ethanol oxidation in the liver perfused with aspartate alone or aspartate in combination with pyruvate, respectively, was increased by about 10% compared to control liver, but not in the tissues perfused with glummate, cysteine or pyruvate alone. Though glummate, cysteine and pyravate did not affect the ethanol oxidation significanfiy, they showed some suppresive effect on the ethanol-induced radical generation monitored by protein carbonylation analysis. Among the tested components, aspartate is confirmed to be the most efficient as a metabolic regulator for both ethanol oxidation and ethanol-induced oxidative stress in our perfusion system. These effects of aspartate would result from NAD recycling by its supplementation through the coupled aspartate aminotransferase/malate dehydrogenase reactions and the malate-aspartate shuttle.

• 한국식품조리과학회지
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• 제32권1호
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• pp.16-26
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• 2016

In this study, we aimed to develop functional vinegar with different levels of black garlic through two stages of fermentation. Black garlic vinegars were prepared from black garlic and water (w/w) mixed with 1:2 (BG3), 1:5 (BG6), 1:9 (BG9) and 1:11 (BG12), and adding the sugar by adjusting the soluble solids content to $14^{\circ}Brix$. The alcohol content of black garlic vinegar was 5.2-5.5% after 7 days of alcohol fermentation at $25^{\circ}C$. Acetic acid fermented was at $30^{\circ}C$ for 25 days and samples were taken at 3, 6, 9, 12, 15, 20 and 25 days. The pH of black garlic vinegar was not significantly different among the samples, but acidity was increased during fermentation. Total polyphenol contents showed irregular changes with the fermentation periods and were higher by black garlic content. At 25 days fermentation, total polyphenol contents were 18.96-56.56 mg/100 mL. Acetic acid content of black garlic vinegars was higher than other organic acids. S-allyl cysteine (SAC) contents of BG3 and BG6 were 13.03-14.54 and 1.69-2.20 mg/L, respectively. However SAC was not detected in BG9 and BG12. In 25 days fermented black garlic vinegar, the major mineral was K with a content ratio of 61-68% of total minerals. The DPPH and ABTS radical scavenging activity of 25 days fermented black garlic vinegar were stronger at higher black garlic content.

• Molecules and Cells
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• 제39권6호
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• pp.495-500
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• 2016

We have solved the crystal structure of a predicted fructose-specific enzyme $IIB^{fruc}$ from Escherichia coli ($EcEIIB^{fruc}$) involved in the phosphoenolpyruvate-carbohydrate phosphotransferase system transferring carbohydrates across the cytoplasmic membrane. $EcEIIB^{fruc}$ belongs to a sequence family with more than 5,000 sequence homologues with 25-99% amino-acid sequence identity. It reveals a conventional Rossmann-like ${\alpha}-{\beta}-{\alpha}$ sandwich fold with a unique ${\beta}$-sheet topology. Its C-terminus is longer than its closest relatives and forms an additional ${\beta}$-strand whereas the shorter C-terminus is random coil in the relatives. Interestingly, its core structure is similar to that of enzyme $IIB^{cellobiose}$ from E. coli ($EcIIB^{cel}$) transferring a phosphate moiety. In the active site of the closest $EcEIIB^{fruc}$ homologues, a unique motif CXXGXAHT comprising a P-loop like architecture including a histidine residue is found. The conserved cysteine on this loop may be deprotonated to act as a nucleophile similar to that of $EcIIB^{cel}$. The conserved histidine residue is presumed to bind the negatively charged phosphate. Therefore, we propose that the catalytic mechanism of $EcEIIB^{fruc}$ is similar to that of $EcIIB^{cel}$ transferring phosphoryl moiety to a specific carbohydrate.

• Molecules and Cells
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• 제44권10호
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• pp.758-769
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• 2021

Calcium homeostasis modulator 1 (CALHM1) is a membrane protein with four transmembrane helices that form an octameric ion channel with voltage-dependent activation. There are four conserved cysteine (Cys) residues in the extracellular domain that form two intramolecular disulfide bonds. We investigated the roles of C42-C127 and C44-C161 in human CALHM1 channel biogenesis and the ionic current (I_CALHM1). Replacing Cys with Ser or Ala abolished the membrane trafficking as well as I_CALHM1. Immunoblotting analysis revealed dithiothreitol-sensitive multimeric CALHM1, which was markedly reduced in C44S and C161S, but preserved in C42S and C127S. The mixed expression of C42S and wild-type did not show a dominant-negative effect. While the heteromeric assembly of CALHM1 and CALHM3 formed active ion channels, the co-expression of C42S and CALHM3 did not produce functional channels. Despite the critical structural role of the extracellular cysteine residues, a treatment with the membrane-impermeable reducing agent tris(2-carboxyethyl) phosphine (TCEP, 2 mM) did not affect I_CALHM1 for up to 30 min. Interestingly, incubation with TCEP (2 mM) for 2-6 h reduced both I_CALHM1 and the surface expression of CALHM1 in a time-dependent manner. We propose that the intramolecular disulfide bonds are essential for folding, oligomerization, trafficking and maintenance of CALHM1 in the plasma membrane, but dispensable for the voltage-dependent activation once expressed on the plasma membrane.

• 한국육종학회지
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• 제42권5호
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• pp.502-506
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• 2010

콩 알레르기에 민감한 사람들은 15가지가 넘는 콩 알레르기 단백질을 인지한다. 이러한 알레르기 단백질 때문에 콩의 광범위한 사용이 제한적이다. 시스테인 프로테아제에 속하는 P34 단백질은 콩의 주된 알러젠이다. 미국 국무부에서 16,226개의 유전자원에서 P34 단백질이 결핍된 PI567476 유전자원을 찾아냈다. P34 유전자 염기서열과 P34 유전자가 결실된 염기서열을 NCBI 데이터베이스에서 확인한 결과 P34 유전자가 결실된 염기서열에서 4 bp 가 삽입되었다는 것을 확인하였고, 그 부위에서 SSLP 마커를 개발하였다. 본 연구에서는 태광콩과 PI567476을 이용한 교배조합 $F_2$ 339개체를 개발한 분자표지마커로 확인하였다. 실험결과 태광콩 유형과 heterozygous 유형 및 PI567476 유형의 분리비는 85: 187: 67로 $X^2{_{0.05}}=5.99$, df=2에서 1:2:1의 분리비로 하나의 유전자가 관여한다는 것으로 나타났다. 앞으로 P34 단백질 관련 분자마커가 단백질 수준에서 정확히 일치하는지 확인 할 것이다.

• 한국식품영양과학회지
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• 제39권9호
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• pp.1313-1319
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• 2010

일품벼에서 유래된 신형질미의 취반 및 가공 등 용도개발을 위한 목적으로 백미와 현미에 대한 성분 분석 및 물리적 특성을 분석한 결과, 원품종인 일품벼과 신형질미인 고아미2호, 백진주, 설갱의 이화학적 특성은 품종 간에 유의한 차이를 보였다. 고아미2호는 고 아밀로스 품종으로 분류되며, 난소화성 다당류의 함량도 높게 나타난 반면에, 백진주는 저아밀로스 품종으로 반 찰벼의 특성을 보였다. 지방산은 백미와 현미에서 linoleic acid와 oleic acid가 전체 지방산의 70~75%를 차지하는 양질의 기름으로서, 백미는 linoleic acid가 현미에는 oleic acid 함량이 높은 경향을 보였다. 한편, 고아미2호는 palmitic acid 함량이 가장 높아서 다른 품종과 다소다른 지방산 조성을 나타내었다. 백미의 주요 아미노산은 aspartic acid, glutamic acid, cysteine, hydroxy lysine이고, 현미에서는 cysteine을 제외한 aspartic acid, glutamic acid, hydroxy lysine인 것으로 나타났다. 쌀 품종의 호화특성을 DSC로 분석한 결과, 호화에 필요한 흡열엔탈피는 반 찰성인 백진주가 가장 높고, 다음은 설갱, 일품, 고아미2호 순으로, 고아미2호가 가장 낮은 흡열엔탈피을 보였다. 취반미의 식미치는 일품벼가 가장 높았으나, 밥의 텍스쳐를 분석한 결과, 고아미2호의 경도가 가장 높고, 일품, 백진주, 설갱 순으로 경도가 낮아지는 것으로 분석되었다. 신형질미 중에서, 고아미2호 취반미는 푸석한 조직감을 보여 다른 품종과는 현저히 다른 특성을 나타내므로, 고아미2호는 취반용 쌀로서 이용하기 보다는 가공용 기능성 곡류 소재로서 활용 가능성이 높으며, 반면에 백진주와 설갱은 원품종인 일품과 비교했을 때 취반용과 가공용도에 모두 적합할 것이다.