• Title/Summary/Keyword: O-GlcNAc

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Purification and characterization of the chitinase from Bacillus subtilis JK-56 (Bacillus subtilis JK-56이 생산하는 chitinase isozyme의 정제와 특성 규명)

  • 전홍기;김낙원;정영기
    • Journal of Life Science
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    • v.12 no.1
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    • pp.77-86
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    • 2002
  • Chitin, a $\beta$-1,4 polymer of N-acetyl-D-glucosamine, is one of the most abundant organic compounds in nature. Chitinase (EC 3.2.1.14) is an enzyme that degrades chitin to chito-oligosaccharides, diacetyl rhitobiose and N-acetyl-D-glucosamine. An extracellular chitinase-producing bacterial strain was isolated from soil and named to as Bacillus subtilis JK-56. Optimum culture condition of B. subtilis JK-56 for the production of chitinase was 1% chitin, 0.5% polypepton, 0.1% KCl, 0.05% MnS $O_4$.4$H_2O$, 37$^{\circ}C$, initial pH 7.0 and 40 hour culture time. When B. subtilis JK-56 was grown in the optimum medium, one major active band and two minor active bands were detected by native-PAGE and active staining of the gel. Among them, the major band was purified from the culture supernatant by 70% ammonium sulfate precipitation and native-PAGE with BIO-RAD Model 491 Prep-Cell and named as Chi-56A. Its molecular weight was estimated to be 53kDa monomer and the isoelectric point (pI) was pH 4.3. The pH and temperature for the optimum activity of Chi-56A were pH 6.0 and $65^{\circ}C$, respectively. Chi-56A was stable up to $65^{\circ}C$ and in alkaline region. Its $K_{m}$ value for colloidal chitin was 17.33g/L. HPLC analysis of the reaction products confirmed that Chi-56A was an exo type chitinase.e.

Developmental Patterns of Gal$\beta$1,3(4)GlcNAc $\alpha$2,3-Sialyltransferase (ST3Gal III) Expression in the Mouse: In Situ Hybridization Using DIG-labeled RNA Probes

  • Ji, Min-Young;Lee, Young-Choon;Kim, Kyoung-Sook;Cho, Jin-Won;Jung, Kyu-Yong;Kim, Cheorl-Ho;Choo, Young-Kug
    • Archives of Pharmacal Research
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    • v.22 no.3
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    • pp.243-248
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    • 1999
  • Sialic acids are key determinants for biological processes, such as cell-cell interaction and differentiation. Sialyltransferases contribute to the diversity in carbohydrate structure through their attachment of sialic acid in various terminal positions on glycolipid and glycoprotein (N-linked and O-linked) carbohydrate groups. Gal$\beta$ 1,3(4)GlcNAc $\alpha$2,3-sialyltransferase (ST3Gal III) is involved in the biosynthesis of $sLe^{X}$ and sLe^{a}$ known as selection ligands and tumor-associated carbohydrate structures. The appearance and differential distribution of ST3Gal III mRNA during mice embryogenesis [embryonic (E) days; E9, E11, E13, E15] were investigated by in situ hybridization with digoxigenin-labeled RNA probes coupled with alkaline phosphatase detection. On E9, all tissues were positive for ST3Gal III mRNA expression whereas ST3Gal III mRNA on E11 was not detected throughout all tissues. On E13, ST3GAl III mRNA was expressed in different manner in various tissues. In this stage, ST3Gal III mRNA was positive only in the liver, pancreas and bladder. On E15, specific signal for ST3GAl III was detected in the liver, lung and forebrain. These results indicate that ST3Gal III is differently expressed at developmental stages of mice embryo, and this may be importantly related with regulation of organogenesis in mice.

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O-GlcNAcylation of NF-κB Promotes Lung Metastasis of Cervical Cancer Cells via Upregulation of CXCR4 Expression

  • Ali, Akhtar;Kim, Sung Hwan;Kim, Min Jun;Choi, Mee Young;Kang, Sang Soo;Cho, Gyeong Jae;Kim, Yoon Sook;Choi, Jun-Young;Choi, Wan Sung
    • Molecules and Cells
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    • v.40 no.7
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    • pp.476-484
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    • 2017
  • C-X-C chemokine receptor 4 (CXCR4) stimulates cancer metastasis. NF-${\kappa}B$ regulates CXCR4 expression in cancer cells, and O-GlcNAc modification of NF-${\kappa}B$ promotes its transcriptional activity. Here, we determined whether CXCR4 expression is affected by O-GlcNAcylation of NF-${\kappa}B$ in lung metastasis of cervical cancer. We found elevated levels of O-linked-N-actylglucosamine transferase (OGT) and O-GlcNAcylation in cervical cancer cells compared to those in non-malignant epithelial cells and detected increased expression of NF-${\kappa}B$ p65 (p65) and CXCR4 in cervical cancer cells. Knockdown of OGT inhibited the O-GlcNAcylation of p65 and decreased CXCR4 expression levels in HeLa cells. Thiamet G treatment increased O-GlcNAcylated p65, which subsequently enhanced CXCR4 expression levels. Inhibition of O-GlcNAcylation by 6-Diazo-5-oxo-L-norleucine (DON) treatment decreased p65 activation, eventually inhibiting CXCR4 expression in HeLa cells. Lung tissues from mice engrafted with OGT-knockdown HeLa cells (shOGT) exhibited lower expression of Ki-67 and HPV E6 and E7 oncogenes compared to lung tissues from mice engrafted with control HeLa cells (shCTL). In addition, lung tissues from mice engrafted with shOGT cells exhibited lower p65 and CXCR4 immunoreactivity compared to tissues from mice engrafted with shCTL cells. Taken together, our data suggest that p65 O-GlcNAcylation promotes lung metastasis of cervical cancer cells by activating CXCR4 expression.

Studies on the Residues of Carbamate Pesticide in Fruits and Vegetables (과일 및 야채의 Carbamate계 농약의 잔류량)

  • 이해금;최용순;최규열
    • Journal of Food Hygiene and Safety
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    • v.2 no.1
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    • pp.3-8
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    • 1987
  • ABSTRACT-Agricultural products collected from the suburbs of Chuncheon in 1984 were analyzed for carbamate pesticides by GLC-NPD. O-tert-butyl phenyl methyl carbamate(BPMC) was detected in most samples and their residue levels in strawberry, tomato, cucumber, grape, apple and chinese cabbage were in the range of non-detectable to 0.2356 ppm(Av. 0.0539 ppm). 1- naphthyl methyl carbamate(N AC) were detected in cucumber, grape and chinese cabbage and their residue levels were in the range of non-detectable to 0.0265 ppm. O-cumeryl methyl carbamate(MIPC) was detected in only chinese cabbage and its residue levels were in the range of non-detectable to 0.0059 ppm. Detection frequencies of BPMC, MIPC and NAC in the chinese cabbage were higher than those the others.others.

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Glucosamine increases vascular contraction through activation of RhoA/Rho kinase pathway in isolated rat aorta

  • Kim, Do-Hyung;Seok, Young-Mi;Kim, In-Kyeom;Lee, In-Kyu;Jeong, Seong-Yun;Jeoung, Nam-Ho
    • BMB Reports
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    • v.44 no.6
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    • pp.415-420
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    • 2011
  • Diabetes is a well-known independent risk factor for vascular disease. However, its underlying mechanism remains unclear. It has been reported that increased influx of the hexosamine biosynthesis pathway (HBP) induces O-GlcNAcylation of proteins, leading to insulin resistance. In this study, we determined whether or not O-GlcNAc modification of proteins could increase vessel contraction. Using an endothelium-denuded aortic ring, we observed that glucosamine induced OGlcNAcylation of proteins and augmented vessel contraction stimulated by U46619, a thromboxane $A_2$ agonist, via augmentation of the phosphorylation of MLC20$MLC_{20}$, MYPT1(Thr855), and CPI17, but not phenylephrine. Pretreatment with OGT inhibitor significantly ameliorated glucosamine-induced vessel constriction. Glucosamine treatment also increased RhoA activity, which was also attenuated by OGT inhibitor. In conclusion, glucosamine, a product of glucose influx via the HBP in a diabetic state, increases vascular contraction, at least in part, through activation of the RhoA/Rho kinase pathway, which may be due to O-GlcNAcylation.