• 한국식품과학회지
• /
• 제22권7호
• /
• pp.802-804
• /
• 1990

${\alpha}-Cyclodextrin(CD)$이 starch-iodine 복합체를 변색시킬 수 있다는 성질을 이용하여 ${\alpha}CD$의 새로운 비색정량법을 확립하였다. 이 새로운 ${\alpha}CD$의 정량법은 다음과 같다. ${\alpha}CD$의 표준용액을 2 mg/ml까지 농도별로 준비하였다. 그리고 동량으로 혼합된 starch-iodine 복합체 용액 1ml에 ${\alpha}CD$ 표준용액 $200\;{\mu}l$와 증류수 3 ml를 함께 가하고, 570 nm에서 흡광도를 측정하였다. 이 방법으로 ${\alpha}CD$의 농도범위는 $0{\sim}2\;mg/ml$까지 측정할 수 있었고, 570 nm에서의 흡광도도 가장 좋은 직선성을 나타내었다. 한편, ${\beta}CD$와 glucose는 ${\alpha}CD$ 정량을 위한 본 방법에 아무런 방해효과가 없었다.

• 한국생물물리학회:학술대회논문집
• /
• 한국생물물리학회 2003년도 정기총회 및 학술발표회
• /
• pp.69-69
• /
• 2003

Human CD99 is a ubiquitous 32-kDa transmembrane protein encoded by the mic2 gene. The major cellular functions of CD99 protein are related to homotypic cell adhension, apoptosis, vesicular protein transport, and differentiation of thymocytes or T cells. Recently it has been reported that expression of a splice variant of CD99 transmembrane protein (Type I and Type II) increases invasive ability of human breast cancer cells. To understand structural basis for cellular functions of CD99 (Type I), we have initiated studies on hCD99$^{TMcytoI}$ and hCD99$^{cytoI}$ using circular dichroism (CD) and multi-dimensional NMR spectroscopy. CD spectrum of hCD99$^{TMcytoI}$ in the presence of 200mM DPC and CHAPS displayed an existence $\alpha$-helical conformation. The solution structure of hCD99$^{cytoI}$ determined by NMR is composed of one N-terminal $\alpha$-helix, $\alpha$A, two C-terminal short $\alpha$-helix segments, $\alpha$B and $\alpha$C. While $\alpha$A and $\alpha$B are connected by the long flexible loop, $\alpha$B and $\alpha$C connected by type III$\beta$-turn. Although it has been rarely figured out the correlation between structure and functional mechanism of hCD99$^{TMcytoI}$ and hCD99$^{cytoI}$, there is possibility of dimerization or oligomerization. In addition, the feasible mechanism of hCD99$^{cytoI}$ is that it could have intramolecular interaction between the N- and C- terminal domain through large flexible AB loop.

• Journal of Microbiology and Biotechnology
• /
• 제17권12호
• /
• pp.1965-1969
• /
• 2007

Triamino ${\alpha}$-cyclodextrin (CD) was synthesized and the inclusion complex with Minoxidil (MXD) was prepared. ${\alpha}$-CD was azidated by modifying the 6-hydroxylmethyl CD rim with sodium azide. Then, mono-, di-, tri-, and tetra-azidocyclodextrins were separated by a flash column chromatography and reduced to the corresponding amines by hydrogenation with Pd/C. The substantivities of MXD included in either 2-hydroxypropyl ${\alpha}$-CD (HP ${\alpha}$-CD) or triamino ${\alpha}$-CD were evaluated in vitro using hairless mice skins. After applying the preparations onto the skin and rinsing it, the amount of the drug left on the skin was determined using high-performance liquid chromatography (HPLC). It was the highest when the drug was included in triamino ${\alpha}$-CD. The electrostatic interaction between the protonated amino CD and the negatively charged skin would be responsible for the relatively high substantivity. The in vivo hair growth promotion effect of each preparation was investigated, where the sample application onto the clipped backs of female mice (C57BL6) and the subsequent rinsing of the backs were done once a day for 30 days. Only MXD in triamino ${\alpha}$-CD had hair growth promotion effect, possibly due to the significant substantivity.

• 대한화학회지
• /
• 제29권2호
• /
• pp.111-120
• /
• 1985

4 mol% Cd-doped ${\alpha}-Fe_2O_3$, 8 mol% Cd-doped ${\alpha}-Fe_2O_3$ 및 12 mol% Cd-doped ${\alpha}-Fe_2O_3$상에서 CO 산화반응이 각기 연구되었다. Cd의 doping level에 관계없이 반응차수는 1.5차이며 CO에 대하여 1차, $O_2$에 대하여 O.5차이다. 350∼$460^{\circ}C$의 반응온도 범위에서 CO산화반응의 활성화 에너지는 10.10∼11.30Kcal/$mol^{-1}$ 이며 Cd-doped${\alpha}-Fe_2O_3$의 전기전도도 데이타와 반응속도 데이타로부터 CO산화반응 메카니즘이 규명되었다. 특히 Cd doping 효과로부터 ${\alpha}-Fe_2O_3$의 촉매활성이 격자산소의 공위에 포획되어 있는 전자의 여기(excitation)에 기인된다는 사실이 밝혀졌으며 반응분자들의 흡착자리를 알게 되었다.

• Biomolecules & Therapeutics
• /
• 제26권5호
• /
• pp.487-493
• /
• 2018

Cluster of differentiation 44 (CD44), a cell surface receptor for hyaluronic acid (HA), is involved in aggressive cancer phenotypes. Herein, we investigated the role of the CD44 standard isoform (CD44s) in hypoxia-inducible $factor-1{\alpha}$ ($HIF-1{\alpha}$) regulation using MCF7 overexpressing CD44s (pCD44s-MCF7). When pCD44s-MCF7 was incubated under hypoxia, levels of $HIF-1{\alpha}$, vascular endothelial growth factor, and the $HIF-1{\alpha}$ response element-derived luciferase activity were significantly increased compared to those in the control MCF7. Incubation of pCD44s-MCF7 cells with HA further increased $HIF-1{\alpha}$ accumulation, and the silencing of CD44s attenuated $HIF-1{\alpha}$ elevation, which verifies the role of CD44s in $HIF-1{\alpha}$ regulation. In addition, the levels of phosphorylated extracellular signal-regulated kinase (ERK) was higher in hypoxic pCD44s-MCF7 cells, and $HIF-1{\alpha}$ accumulation was diminished by the pharmacological inhibitors of ERK. CD44s-mediated $HIF-1{\alpha}$ augmentation resulted in two functional outcomes. First, pCD44s-MCF7 cells showed facilitated cell motility under hypoxia via the upregulation of proteins associated with epithelial-mesenchymal transition, such as SNAIL1 and ZEB1. Second, pCD44s-MCF7 cells exhibited higher levels of glycolytic proteins, such as glucose transporter-1, and produced higher levels of lactate under hypoxa. As a consequence of the enhanced glycolytic adaptation to hypoxia, pCD44s-MCF7 cells exhibited a higher rate of cell survival under hypoxia than that of the control MCF7, and glucose deprivation abolished these differential responses of the two cell lines. Taken together, these results suggest that CD44s activates hypoxia-inducible $HIF-1{\alpha}$ signaling via ERK pathway, and the $CD44s-ERK-HIF-1{\alpha}$ pathway is involved in facilitated cancer cell viability and motility under hypoxic conditions.

• 한국생물공학회:학술대회논문집
• /
• 한국생물공학회 2001년도 추계학술발표대회
• /
• pp.662-665
• /
• 2001

PLE를 이용한 levofloxacin의 생산에서 기질 150 mM 사용의 경우 두배의 몰농도 로 ${\alpha}-CD$를 사용하여 산물의 생산량을 3.7 배까지 증가시킬 수 있었다. 그러나 이 경우 ${\alpha}-CD$의 사용량이 많아 경제성이 떨어지는 단점이 있다. 이에 같은 몰농도로 ${\alpha}-CD$를 사용하고 pH에 변화를 주어 용해도를 향상시켜 보았다. 기질 100 mM의 경우 pH 5.6에서 같은 몰농도의 ${\alpha}-CD$를 사용한 경우 ${\alpha}-CD$를 사용하지 않은 것에 비해 4.4배의 수율의 증대가 있었다.

• KSBB Journal
• /
• 제10권5호
• /
• pp.491-498
• /
• 1995

Cyclodextrin의 고순도 분획, 정제를 위한 CD adsorbent의 제조에 척합한 matnx를 선별하기 위하여 capric acid를 ligand로 각종 이온교환수지를 비교 검토한 결과 DEAE Cellulose가 가장 적합함을 알았다. DEAE Cellulose와 capric acid간의 결합 안정성은 온도, ionic strength의 변화에 영향을 받았으며, ethanol 농도의 변화에는 안정하였다. CD adsorbent의 흡착량, 탈착량, 그리고 ${\alpha}$-, ${\beta}$- 및 ${\gamma}$-CD 의 용출양상을 규명하였다. 탄소쇄가 다른 각종 포화, 불포화 fatty acid를 ligand로 하여 specific adsorbent를 제조하였으며, ${\alpha}$-, ${\beta}$- 및 ${\gamma}$-CD의 회수율과 분리능을 비교 검토 하였다. 그 결과 steanc a acid는 ${\alpha}$-CD 그리고 linoleic acid는 ${\beta}$-CD에 대하여 높은 회수율과 선택성을 보였으며, 선택성은 fatty acid의 탄소쇄 길이와 이중결합 유무에 의하여 영향을 받았다. Stearic acid와 linoleic acid CD adsorbents를 이용하여 CD 혼합물로부터${\alpha}$-, ${\beta}$- 및 ${\gamma}$-CD의 분획양상을 검토하였다.

• Journal of Photoscience
• /
• 제3권3호
• /
• pp.153-158
• /
• 1996

The effects of $\alpha$- and $\beta$-cyclodextrins (CD) on the twisted intramolecular charge transfer (TICT) behavior of p-N,N'-dimethylaminobenzoic acid (DMABA) in buffered aqueous solution have been investigated by examining formation and decay behaviors of the TICT-typical dual fluorescence. The ratio of the TICT emission to the normal emission (I$_a$/I$_b$) increases linearly $\alpha$-CD concentration increases, while in the presence of $\beta$-CD it shows nonlinear dependences on the CD concentration. The analysis of the CD-dependent changes of the I$_a$/I$_b$ and absorption spectra demonstrates formation of 1:1 inclusion complexes between DMABA and CDs. The decay time of the normal emission (ca. 700 ps) is little affected by the formation of $\alpha$-CD inclusion complex, whereas it increases upto ca. 1.6 ns upon formation of $\beta$-CD inclusion complex. The TICT emission for the $\beta$-CD inclusion complex exhibits two decay components while it shows a single component for the $\alpha$-CD inclusion complex, indicating formation of one or two types of inclusion complex in the presence of $\alpha$-CD or $\beta$-CD, respectively. These results are attributed to the CD cavity size dependence on patterns of complexation between CDs and DMABA. The CD size dependences of the TICT fluorescence properties with the orientation of the guest molecule demonstrate that the specific hydrogen bonding between the carboxylic acid group and water plays an important role in the excited-state TICT.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• 제18권1호
• /
• pp.153-163
• /
• 1996

Macrophage inflammatory protein $(MIP)-1{\alpha}$ is a cytokine which produces wide range of bioactivities such as proinflammatory, immunomodulatory, and hematopoietic modulatory actions. To determine whether $MIP-1{\alpha}$ acts as a negative regulator on the functions of lymphocyte, $[^3H]$-thymidine incorporation test and flow cytometric analysis were performed by using human tonsil T cell, human peripheral blood T cell, and murine cytolytic T lymphocyte (CTL) line CTLL-2, The results were as follow. 1. When human tonsil T lymphocytes were stimulated with anti-CD3 monoclonal antibody (mAb), rate of T cell proliferation was about four times increased. 200ng/ml of $MIP-1{\alpha}$ inhibited anti-CD3 mAb-mediated T cell growth as much as 60% (P<0.05). 2. The suppression of human peripheral T cell proliferation produced by $MIP-1{\alpha}$ was dramatic, but variable among T cells derived from different individuals $(40%{\sim}90%)$. 3. $MIP-1{\alpha}$inhibited the proliferation of murine CTL line CTLL-2 as much as 75%(P<0.001). 4. When the $MIP-1{\alpha}$ was added to human peripheral T cell, cell proporation of $CD4^+$ helper T cell and $CD8^+$ CTL were not noticeably affected. The expression level of CD4, not of Cd8, however, was down regulated by $MIP-1{\alpha}$ treatment $(27%{\sim}82%)$.

• BMB Reports
• /
• 제47권5호
• /
• pp.241-248
• /
• 2014

CD1 molecules belong to non-polymorphic MHC class I-like proteins and present lipid antigens to T cells. Five different CD1 genes (CD1a-e) have been identified and classified into two groups. Group 1 include CD1a-c and present pathogenic lipid antigens to ${\alpha}{\beta}$ T cells reminiscence of peptide antigen presentation by MHC-I molecules. CD1d is the only member of Group 2 and presents foreign and self lipid antigens to a specialized subset of ${\alpha}{\beta}$ T cells, NKT cells. NKT cells are involved in diverse immune responses through prompt and massive production of cytokines. CD1d-dependent NKT cells are categorized upon the usage of their T cell receptors. A major subtype of NKT cells (type I) is invariant NKT cells which utilize invariant $V{\alpha}14-J{\alpha}18$ TCR alpha chain in mouse. The remaining NKT cells (type II) utilize diverse TCR alpha chains. Engineered CD1d molecules with modified intracellular trafficking produce either type I or type II NKT cell-defects suggesting the lipid antigens for each subtypes of NKT cells are processed/generated in different intracellular compartments. Since the usage of TCR by a T cell is the result of antigen-driven selection, the intracellular metabolic pathways of lipid antigen are a key in forming the functional NKT cell repertoire.