• Bulletin of the Korean Chemical Society
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• 제32권1호
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• pp.31-32
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• 2011

• Bulletin of the Korean Chemical Society
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• 제31권12호
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• pp.3812-3814
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• 2010

• Bulletin of the Korean Chemical Society
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• 제25권9호
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• pp.1303-1304
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• 2004

• 대한약리학회지
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• 제27권1호
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• pp.7-12
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• 1991

쥐(태령 14일) 뇌간 세포배양에서 발달과정에 따른 Tyrosine hydroxylase(TH) 활성 및 dopamine의 양적 증가를 전기화학 HPLC를 이용하여 측정하였다. TH 활성 및 dopamine의 양은 배양 7일까지 점차 증가하였다. 배양 7일째에 여러 약물들의 dopamine 대사에 대한 영향을 조사하였다. TH 억제제인 ${\alpha}-methyl-p-tyrosine$ 및 aromatic amiono acid decarboxylase 억제제인 NSD-1015는 효과적으로 dopamine을 고갈시켰다. Dopamine은 reserpine에 의해 고갈되었고, parglyine에 의해 증가되었다. 일주일 배양한 세포의 배양액에 tetrodotoxin$(0.1\;{\mu}M$)을 7일간 투여하였을 때 TH 활성은 현저히 감소하였다. 이상의 결과들은 배양세포의 dopamine 대사가 뇌 dopamine 대사를 충실히 반영함을 나타낸다. 뇌간 세포의 배양에서 HPLC-전기화학검출을 이용한 TH 활성 및 dopamine의 측정은 중추 dopamine계의 약리 및 독성 연구에 유용하리라 사료된다.

• ALGAE
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• 제19권3호
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• pp.271-276
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• 2004

One hundred and fifty four micro algal strains, newly isolated from nationwide freshwaters in Korea, were screened for their anticancer, ant diabetic, and antibiotic activities. The micro algal strains were cultured with different nutritional conditions that were divided into 4 groups as follows; a normal Allen medium, nitrogen (N)-limited medium, phosphorus (P)-limited medium, and N and P-limited medium. Algal biomass was extracted with a mixture of acetone:H₂O (1:1, v:v) and the extracts were used for the screening of bioactive materials. Anticancer, ant diabetic, and antibiotic materials were screened by the methods of vaccinia Hl-related protein tyrosine phosphates (VHR DS-PTPase) inhibition, protein tyrosine phosphates 1B (PTP1B) inhibition, and paper disk. The inhibition activity of VHR DS-PTPase was observed in 18 strains, having a maximum 79% inhibition from Anabaena affinis and the inhibition activity of PTP1B was observed in 9 strains, having a maximum 97% from Sphaerocystis schroeteri. Microcystis aeruginosa incubated in an N and P-limited medium showed antibiotic activity in 8 species out of 13 pathogenic bacteria. As a whole, it seemed that the stressed condition such as N and/or P limitation increased the production of bioactive materials in micro algae.

• Bulletin of the Korean Chemical Society
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• 제29권8호
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• pp.1479-1484
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• 2008

Protein tyrosine phosphatase (PTP) 1B is the superfamily of PTPs and a negative regulator of multiple receptor tyrosine kinases (RTKs). Inhibition of protein tyrosine phosphatase 1B (PTP1B) has been proposed as a strategy for the treatment of type 2 diabetes and obesity. Recently, it has been reported that amentoflavone, a biflavonoid extracted from Selaginella tamariscina, inhibited PTP1B. In the present study, docking model between amentoflavone and PTP1B was determined using automated docking study. Based on this docking model and the interactions between the known inhibitors and PTP1B, we determined multiple pharmacophore maps which consisted of five features, two hydrogen bonding acceptors, two hydrogen bonding donors, and one lipophilic. Using receptor-oriented pharmacophore-based in silico screening, we searched the biflavonoid database including 40 naturally occurring biflavonoids. From these results, it can be proposed that two biflavonoids, sumaflavone and tetrahydroamentoflavone can be potent allosteric inhibitors, and the linkage at 5',8''-position of two flavones and a hydroxyl group at 4'-position are the critical factors for their allosteric inhibition. This study will be helpful to understand the mechanism of allosteric inhibition of PTP1B by biflavonoids and give insights to develop potent inhibitors of PTP1B.

• 대한약리학회지
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• 제17권1호
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• pp.33-39
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• 1981

In this paper, the influences of adrenergic neuronal blockades of different mode: guanethidine and ${\alpha}$-methyl-para-tyrosine on the changes induced by carbon tetrachloride $(CCl_4)$ of hepatic total lipid, glycogen, and lipid peroxide contents and serum lactic dehydrogenase activity were investigated in male mice. The results obtained were summarized as follows: 1) The hepatic total lipid and lipid peroxide contents and serum lactic dehydrogenase activity were markedly increased by $CCl_4$, but hepatic glycogen content were decreased. 2) The hepatic total lipid and lipid peroxide contents and serum lactic dehydrogenase activity were not significantly changed by guanethidine(20mg/kg) or ${\alpha}$-methyl-para-tyrosine (5 mg/kg) injection. 3) The increase of hepatic total lipid induced by $CCl_4$ was inhibited by the pretreatment of guanethidine or ${\alpha}$-methyl-para-tyrosine, and the increase of hepatic lipid peroxide content induced by $CCl_4$ was slightly inhibited by them. But the decrease of hepatic glycogen content and the increase of serum lactic dehydrogenase activity induced by $CCl_4$ were not affected by them.

• BMB Reports
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• 제28권4호
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• pp.316-322
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• 1995

The GTPase activating protein (GAP) can function both as a negative regulator and an effector of $p21^{ras}$. Overexpression of GAP in NIH-3T3 cells has been shown to inhibit transformation by ms or src. To investigate the function of GAP in a differentiative system, we overexpressed this protein in the nerve growth factor (NGF)-responsive PC12 cell line. Two-fold overexpression of GAP caused a delay of several days in the onset of NGF- but not FGF-induced neuronal differentiation of PC12 cells. However, the NGF-induced activation or tyrosine phosphorylation of upstream (Trk, PLC-${\gamma}1$, SHC) and downstream (B-Raf and $p44^{mapk/erk1}$) components of $p21^{ras}$, signalling cascade was not altered by GAP overexpression. Therefore, the change of phenotype induced by GAP was probably not due to GAP functioning as a negative regulator of $p21^{ras}$. Rather, we found that NGF-induced tyrosine phosphorylation of SNT, a specific target of neurotrophin-induced tyrosine kinase activity, was inhibited by GAP overexpression. SNT is thought to function upstream or independent of $p21^{ras}$. Thus in PC12 cells, overexpressed GAP may control the rate of neuronal differentiation through a pathway involving SNT rather than the $p21^{ras}$ signalling pathway.

• 한국잠사곤충학회지
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• 제39권2호
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• pp.169-173
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• 1997

The behavior of tyrosine(Tyr.) residue of Bombyx mori silk fiber from yellow fluorescent cocoon has been examined for the dependence of pH in aqueous silk solution under the presence of orange II salt. Through the peak separation of angular dependence of spectral pattern of 15N-Tyr. and [1-13C]-Tyr. between the fiber axis and the molecular bond direction, N-H bond in fiber as well as the orientation distribution around the fiber axis were analyzed. Also, and sericin component was obtained from these angular dependence of oriented spectral pattern. The pH dependence of the 13C NMR chemical shift of B. mori silk fibroin was examined in aqueous solution in the presince of orange II are broad at pH$\geq$7.0. However, these become sharper at pH$\geq$8.0 and remain sharp at higher pH. In these higher pH range, a chemical shift change occurs due to the deprotonation of the Tyr. side group of fibroin. At higher pH. such a hydrophobic cluster is destroyed because of the electrostatic interaction according to the deprotonation of the Tyr-OH group.

• Journal of Plant Biotechnology
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• 제42권4호
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• pp.277-283
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• 2015

Plant genome analyses, including Arabidopsis thaliana showed a large gene family of plant receptor kinases with various extracellular ligand-binding domain. Now intensively studies to understand physiological and cellular functions for higher plant receptor kinases in diverse and complex biological processes including plant growth, development, ligands perception including steroid hormone and plant-microbe interactions. Brassinosteroids (BRs) as a one of well know steroid hormone are plant growth hormones that control biomass accumulation and also tolerance to many biotic and abiotic stress conditions and hence are of relevance to agriculture. BRI1 receptor kinase, which is localized in plasma membrane in the cell sense BRs and it bind to a receptor protein known as BRASSINOSTEROID INSENSITIVE 1 (BRI1). Recently, we reported that BRI1 and its co-receptor, BRI1-ASSOCIATED KINASE (BAK1) autophosphorylated on tyrosine residue (s) in vitro and in vivo and thus are dual-specificity kinases. Other plant receptor kinases are also phosphorylated on tyrosine residue (s). Post-translational modifications (PTMs) can be studied by altering the residue modified by directed mutagenesis to mimic the modified state or to prevent the modification. These approaches are useful to not only characterize the regulatory role of a given modification, but may also provide opportunities for plant improvement.