• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.11
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• pp.5179-5186
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• 2012

Miglitol, a well-known therapeutic intervention agents for diabetes, exhibits competitive inhibitory activity against ${\alpha}$-glucosidase and it is usually produced through three sequential steps including chemical and bioconversion processes. Gluconobactor oxydans (G. oxydans) belonging to acetic acid bacteria biologically, converts 1-deoxy-1-(2-hydroxyethylamino)-D-glucitol (P1) into a key intermidiate, 6-(2-hydroxyetyl) amino-6-deoxy-${\alpha}$-L-sorbofuranose (P2) by incomplete oxidation. In this study, we identified and optimized fermentation conditions of CK-2165, that was selected in soil samples by comparing the bioconversion yield. CK-2165 strain was found to be closely related to G. oxydans based on the result of phylogenetic analysis using 16S rDNA sequence. Utilization of API 20 kits revealed that this strain could use glucose, mannose, inositol, sorbitol, rhamnose, sucrose, melibiose, amygdalin and arabinose as carbon sources. The culture conditions were optimized for industrial production and several important factors affecting bioconversion rate were also tested using mycelial cake. Cell harvested at the late-stationary phase showed the highest bioconversion yield and $MgSO_4$ was critically required for the catalytic activity.

• Nutrition Research and Practice
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• v.10 no.3
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• pp.259-264
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• 2016

BACKGROUND/OBJECTIVES: Stromal cell-derived growth factor 1 (SDF-1), also known as chemokine ligand 12, and chemokine receptor type 4 are involved in cancer cell migration. Compound K (CK), a metabolite of protopanaxadiol-type ginsenoside by gut microbiota, is reported to have therapeutic potential in cancer therapy. However, the inhibitory effect of CK on SDF-1 pathway-induced migration of glioma has not yet been established. MATERIALS/METHODS: Cytotoxicity of CK in C6 glioma cells was determined using an EZ-Cytox cell viability assay kit. Cell migration was tested using the wound healing and Boyden chamber assay. Phosphorylation levels of protein kinase C $(PKC){\alpha}$ and extracellular signal-regulated kinase (ERK) were measured by western blot assay, and matrix metallopeptidases (MMP) were measured by gelatin-zymography analysis. RESULTS: CK significantly reduced the phosphorylation of $PKC{\alpha}$ and ERK1/2, expression of MMP9 and MMP2, and inhibited the migration of C6 glioma cells under SDF-1-stimulated conditions. CONCLUSIONS: CK is a cell migration inhibitor that inhibits C6 glioma cell migration by regulating its downstream signaling molecules including $PKC{\alpha}$, ERK1/2, and MMPs.

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.545-549
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• 2003

After irradiation of a cloned dextransucrase gene (dsrB742) with ultrasoft X-ray, an E. coli transformant (pDSRB742CK) was first developed for the expression of an extracellular dextransucrase, having increased activity and the synthesis of a highly branched dextran. Seven nucleotides of the parent gene (dsrB742) were changed in the nucleotide sequences of dsrB742ck. Among them, four nucleotides were changed at the ORF of dsrB742, resulting in a 30 amino acids deletion in the N-terminal of DSRB742 dextransucrase. The activity of DSRB742CK dextransucrase in culture supernatant was approximately 2.6 times higher (0.035 IU/ml) than that of the DSRB742 clone. The pDSRB742CK clone produced DSRB742CK dextransucrase when grown both on a sucrose medium (inducibly) and on a glucose medium (constitutively). The DSRB742 clone did not produce dextran constitutively on a glucose medium. DSRB742CK dextran had 15.6% branching and 2.7-times higher resistance to dextranase hydrolysis compared to DSRB742 dextran. $^{13}C-NMR$ showed that DSRB742CK dextran contained ${\alpha}-(1{\rightarrow}3)$ branch linkages that were not present in DSRB742 dextran.

• Journal of Ginseng Research
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• v.43 no.1
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• pp.154-160
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• 2019

Background: Compound K (CK) is an active metabolite of ginseng saponin, ginsenoside Rb1, that has been shown to have ameliorative properties in various diseases. However, its role in inflammation and the underlying mechanisms are poorly understood. In this report, the antiinflammatory role of CK was investigated in macrophage-like cells. Methods: The CK-mediated antiinflammatory mechanism was explored in RAW264.7 and HEK293 cells that were activated by lipopolysaccharide (LPS) or exhibited overexpression of known activation proteins. The mRNA levels of inflammatory genes and the activation levels of target proteins were identified by quantitative and semiquantitative reverse transcription polymerase chain reaction and Western blot analysis. Results: CK significantly inhibited the mRNA expression of inducible nitric oxide synthase and tumor necrosis factor-${\alpha}$ and morphological changes in LPS-activated RAW264.7 cells under noncytotoxic concentrations. CK downregulated the phosphorylation of AKT1, but not AKT2, in LPS-activated RAW264.7 cells. Similarly, CK reduced the AKT1 overexpression-induced expression of aldehyde oxidase 1, interleukin-$1{\beta}$, interferon-${\beta}$, and tumor necrosis factor-${\alpha}$ in a dose-dependent manner. Conclusion: Our results suggest that CK plays an antiinflammatory role during macrophage-mediated inflammatory actions by specifically targeting the AKT1-mediated signaling pathway.

• Journal of Ginseng Research
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• v.42 no.2
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• pp.218-224
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• 2018

Background: Compound K (CK) is a ginsenoside, a metabolite of Panax ginseng. There is interest both in increasing skin health and antiaging using natural skin care products. In this study, we explored the possibility of using CK as a cosmetic ingredient. Methods: To assess the antiaging effect of CK, RT-PCR was performed, and expression levels of matrix metalloproteinase-1, cyclooxygenase-2, and type I collagen were measured under UVB irradiation conditions. The skin hydrating effect of CK was tested by RT-PCR, and its regulation was explored through immunoblotting. Melanin content, melanin secretion, and tyrosinase activity assays were performed. Results: CK treatment reduced the production of matrix metalloproteinase-1 and cyclooxygenase-2 in UVB irradiated NIH3T3 cells and recovered type I collagen expression level. Expression of skin hydrating factors-filaggrin, transglutaminase, and hyaluronic acid synthases-1 and -2-were augmented by CK and were modulated through the inhibitor of ${\kappa}B{\alpha}$, c-Jun N-terminal kinase, or extracellular signal-regulated kinases pathway. In the melanogenic response, CK did not regulate tyrosinase activity and melanin secretion, but increased melanin content in B16F10 cells was observed. Conclusion: Our data showed that CK has antiaging and hydrating effects. We suggest that CK could be used in cosmetic products to protect the skin from UVB rays and increase skin moisture level.

• BMB Reports
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• v.55 no.4
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• pp.192-197
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• 2022

Cell signals for growth factors depend on the mechanical properties of the extracellular matrix (ECM) surrounding the cells. Microtubule acetylation is involved in the transforming growth factor (TGF)-β-induced myofibroblast differentiation in the soft ECM. However, the mechanism of activation of α-tubulin acetyltransferase 1 (α-TAT1), a major α-tubulin acetyltransferase, in the soft ECM is not well defined. Here, we found that casein kinase 2 (CK2) is required for the TGF-β-induced activation of α-TAT1 that promotes microtubule acetylation in the soft matrix. Genetic mutation and pharmacological inhibition of CK2 catalytic activity specifically reduced microtubule acetylation in the cells cultured on a soft matrix rather than those cultured on a stiff matrix. Immunoprecipitation analysis showed that CK2α, a catalytic subunit of CK2, directly bound to the C-terminal domain of α-TAT1, and this interaction was more prominent in the cells cultured on the soft matrix. Moreover, the substitution of alanine with serine, the 236th amino acid located at the C-terminus, which contains the CK2-binding site of α-TAT1, significantly abrogated the TGF-β-induced microtubule acetylation in the soft matrix, indicating that the successful binding of CK2 and the C-terminus of α-TAT1 led to the phosphorylation of serine at the 236th position of amino acids in α-TAT1 and regulation of its catalytic activity. Taken together, our findings provide novel insights into the molecular mechanisms underlying the TGF-β-induced activation of α-TAT1 in a soft matrix.

• Journal of Microbiology and Biotechnology
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• v.18 no.2
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• pp.295-298
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• 2008

Creatine kinase (CK; E.C. 2.7.3.2) is an important enzyme that catalyzes the reversible transfer of a phosphoryl group from ATP to creatine in energy homeostasis. The brain-type cytosolic isoform of creatine kinase (BB-CK), which is found mainly in the brain and retina, is a key enzyme in brain energy metabolism, because high-energy phosphates are transfered through the creatine kinase/phosphocreatine shuttle system. The recombinant human BB-CK protein was overexpressed as a soluble form in Escherichia coli and crystallized at $22^{\circ}C$ using PEG 4000 as a precipitant. Native X-ray diffraction data were collected to $2.2{\AA}$ resolution using synchrotron radiation. The crystals belonged to the tetragonal space group $P4_32_12$, with cell parameters of a=b=97.963, $c=164.312{\AA},\;and\;{\alpha}={\beta}={\gamma}=90^{\circ}$. The asymmetric unit contained two molecules of CK, giving a crystal volume per protein mass $(V_m)$ of $1.80{\AA}^3\;Da^{-1}$ and a solvent content of 31.6%.

• Journal of Ginseng Research
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• v.43 no.1
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• pp.95-104
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• 2019

Background: Oxidized low-density lipoprotein (ox-LDL) causes vascular endothelial cell inflammatory response and apoptosis and plays an important role in the development and progression of atherosclerosis. Ginsenoside compound K (CK), a metabolite produced by the hydrolysis of ginsenoside Rb1, possesses strong anti-inflammatory effects. However, whether or not CK protects ox-LDL-damaged endothelial cells and the potential mechanisms have not been elucidated. Methods: In our study, cell viability was tested using a 3-(4, 5-dimethylthiazol-2yl-)-2,5-diphenyl tetrazolium bromide (MTT) assay. Expression levels of interleukin-6, monocyte chemoattractant protein-1, tumor necrosis factor-${\alpha}$, intercellular adhesion molecule-1, and vascular cell adhesion molecule-1 were determined by enzyme-linked immunosorbent assay and Western blotting. Mitochondrial membrane potential (${\Delta}{\Psi}m$) was detected using JC-1. The cell apoptotic percentage was measured by the Annexin V/ propidium iodide (PI) assay, lactate dehydrogenase, and caspase-3 expression. Apoptosis-related proteins, nuclear factor $(NF)-{\kappa}B$, and mitogen-activated protein kinases (MAPK) signaling pathways protein expression were quantified by Western blotting. Results: Our results demonstrated that CK could ameliorate ox-LDL-induced human umbilical vein endothelial cells (HUVECs) inflammation and apoptosis, $NF-{\kappa}B$ nuclear translocation, and the phosphorylation of p38 and c-Jun N-terminal kinase (JNK). Moreover, anisomycin, an activator of p38 and JNK, significantly abolished the anti-apoptotic effects of CK. Conclusion: These results demonstrate that CK prevents ox-LDL-induced HUVECs inflammation and apoptosis through inhibiting the $NF-{\kappa}B$, p38, and JNK MAPK signaling pathways. Thus, CK is a candidate drug for atherosclerosis treatment.

• The Korean Journal of Pharmacology
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• v.29 no.2
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• pp.263-274
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• 1993

Potassium $(K^+)$ channels are present in airway smooth muscle cells, and their activation results in hyperpolarization and relaxation. Because these effects may have therapeutic relevance to hypersensitivity and asthma, we examined the effect of a potassium channel activator, cromakalim (BRL 34915, CK) on the release of mediators from superfused tracheal and parenchymal strips after passive sensitization with $IgG_1$ antibody. Both tissues were superfused with CK $(2{\times}10^{-6}\;M)$ for 30 min and challenged with CK and antigen (Ox-HSA). Using monodispersed, partially purified, highly purified guinea pig lung mast cells, we also examined the effect of CK on mediator release from these cells after passive sensitization with $IgG_{1}$ antibody $({\alpha}-OA)$. Guinea pig lung mast cells were purified using enzyme digestion method, count current elutriation, and discontinuous Percoll density gradient. After CK pretreatment, passively sensitized mast cells were challenged with varying concentration of antigen (OA, immunological stimuli) or with varying concentration of calcium ionophore (CaI, non-immunological stimuli). Histamine (Hist) release was determined by spectrophotofluorometry, and leukotrienes (LT) by radioimmunoassy. CK pretreatment decreased Hist by 35% and LT release by 40% in the antigen-induced tracheal tissue after $IgG_1$ sensitization but did not decrease the contractile response. In the antigen-induced parenchymal tissue CK decreased Hist release by 25% but poorly decreased LT. Both immunologic and non-immunologic stimuli caused a dose-dependent release of Hist and LT from monodispersed, partially purified and highly purified lung mast cells. Verification of LT release was obtained by the use of 5-lipoxygenase inhibitor, A64077 (Zileuton). CK decreased Hist and LT release by 20% respectively in the OA-induced guinea pig lung mast cells after $IgG_1$ sensitization. The inhibitory effects of CK on the Hist and LT release in the Ox-HSA-induced airway smooth muscle tissues or in the OA-induced and CaI-induced mast cells after $IgG_1$ sensitization were completely blocked by TEA and GBC. These studies show that guinea pig lung mast cells seem to be an important contributor to LT release, and that CK (which has been known as an airway smooth muscle relaxant) can in part act to inhibit mediator release in the antigen-induced airway smooth muscle, and that CK may also act to inhibit mediator release in the OA-induced and CaI-induced highly purified mast cells. These results suggest that Hist and LT release evoked by mast cell activation might in part be associated with $K{^+}4 channel activity.

• Molecules and Cells
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• v.21 no.1
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• pp.52-62
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• 2006

In previous reports we demonstrated that ginsenosides, active ingredients of Panax ginseng, affect some subsets of voltage-dependent $Ca^{2+}$ channels in neuronal cells expressed in Xenopus laevis oocytes. However, the major component(s) of ginseng that affect cloned $Ca^{2+}$ channel subtypes such as ${\alpha}_{1C}$(L)-, ${\alpha}_{1B}$(N)-, ${\alpha}_{1A}$(P/Q)-, ${\alpha}_{1E}$(R)- and ${\alpha}_{1G}$(T) have not been identified. Here, we used the two-microelectrode voltage clamp technique to characterize the effects of ginsenosides and ginsenoside metabolites on $Ba^{2+}$ currents ($I_{Ba}$) in Xenopus oocytes expressing five different $Ca^{2+}$ channel subtypes. Exposure to ginseng total saponins (GTS) induced voltage-dependent, dose-dependent and reversible inhibition of the five channel subtypes, with particularly strong inhibition of the ${\alpha}_{1G}$-type. Of the various ginsenosides, $Rb_1$, Rc, Re, Rf, $Rg_1$, $Rg_3$, and $Rh_2$, ginsenoside $Rg_3$ also inhibited all five channel subtypes and ginsenoside $Rh_2$ had most effect on the ${\alpha}_{1C}$- and ${\alpha}_{1E}$-type $Ca^{2+}$ channels. Compound K (CK), a protopanaxadiol ginsenoside metabolite, strongly inhibited only the ${\alpha}_{1G}$-type of $Ca^{2+}$ channel, whereas M4, a protopanaxatriol ginsenoside metabolite, had almost no effect on any of the channels. $Rg_3$, $Rh_2$, and CK shifted the steady-state activation curves but not the inactivation curves in the depolarizing direction in the ${\alpha}_{1B}$- and ${\alpha}_{1A}$-types. These results reveal that $Rg_3$, $Rh_2$ and CK are the major inhibitors of $Ca^{2+}$ channels in Panax ginseng, and that they show some $Ca^{2+}$ channel selectivity.