• Reproductive and Developmental Biology
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• v.34 no.4
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• pp.289-297
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• 2010

Erythropoietin (EPO) is a glycoprotein hormone secreted from primarily cells of the peritubular capillary endothelium of the kidney, and is responsible for the regulation of red blood cell production. We constructed and expressed dimeric cDNAs in Chinease hamster ovary (CHO) cells encoding a fusion protein consisting of 2 complete human EPO domains linked by a 2-amino acid linker (Ile-Asp). We described the activity of dimeric hyperglycosylated EPO (dHGEPO) mutants containing additional oligosaccharide chains and characterized the function of glycosylation. No dimeric proteins with mutation at the $105^{th}$ amino acid were found in the cell medium. Growth and differentiation of the human EPO-dependent leukemiae cell line (F36E) were used to measure cytokine dependency and in vitro bioactivity of dHGEPO proteins. MIT assay at 24 h increased due to the survival of F36E cells. The dHGEPO protein migrated as a broad band with an average molecular mass of 75 kDa. The mutant, dHGEPO, was slightly higher than the wild-type (WT) dimeri-EPO band. Enzymatic N-deglycosylation resulted in the formation of a narrow band with a molecular mass twice of that of of monomeric EPO digested with an N-glycosylation enzyme. Hematocrit values were remarkably increased in all treatment groups. Pharmacokinetic analysis was also affected when 2.5 IU of dHGEPO were intravenously injected into the tails of the mice. The biological activity and half-life of dHGEPO mutants were enhanced as compared to the corresponding items associated the WT dimeric EPO. These results suggest that recombinant dHGEPO may be attractive biological and therapeutic targets.

• Preventive Nutrition and Food Science
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• v.1 no.1
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• pp.111-116
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• 1996

Polyphenol oxidase(PPO) isolated from the crude extract of ascidian, Halocynthia roretzi, showed higher affinity for catechol than tyrosine or DL-DOPA. Successful enzyme assay could be performed at $25^{\circ}C$, 10min. by mixing 0.2ml of crude enzyme extract with 2.8ml of 0.13M catechol in 0.1M sodium phosphate buffer(pH 6.4). The specific activity of PPO which had been purified with a combination of ammonium sulfate treatment, ion exchange chromatography on DEAE-cellulose, and gel filtration on Sepharose 6B was 13-fold disc gel electrophoresis. The activity of PPO was stable from pH 5.0 to 8.0 and showed the peak activity at pH 6.4 .The optimum reaction temperature for PPO oxidation on catechol was 35$^{\circ}C$ and those enzyme were heat stable up to 4$0^{\circ}C$. Molecular weigth of the enzyme was estimated about 170kDa. One molecule was found to be composed of gour subunits. Two of them had molecular weigh of 55kDa and the others 30kDa. The {TEX}$K_{m}${/TEX} values, {TEX}$V_{max}${/TEX} and catalytic efficiency({TEX}$V_{max}${/TEX}/{TEX}$K_{m}${/TEX}) for catechol were 0.12mM, 2.5mM/liter/min. and {TEX}$0.18min^{-1}${/TEX} respectively. The substrate affinity and electrophorectic pattern suggested that the enzyme of ascidian was considered to be not tyosine but catechol oxidase.

• Journal of Microbiology and Biotechnology
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• v.29 no.2
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• pp.244-255
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• 2019

Xylose isomerase (XI; E.C. 5.3.1.5) catalyzes the isomerization of xylose to xylulose, which can be used to produce bioethanol through fermentation. Therefore, XI has recently gained attention as a key catalyst in the bioenergy industry. Here, we identified, purified, and characterized a XI (PbXI) from the psychrophilic soil microorganism, Paenibacillus sp. R4. Surprisingly, activity assay results showed that PbXI is not a cold-active enzyme, but displays optimal activity at $60^{\circ}C$. We solved the crystal structure of PbXI at $1.94-{\AA}$ resolution to investigate the origin of its thermostability. The PbXI structure shows a $({\beta}/{\alpha})_8$-barrel fold with tight tetrameric interactions and it has three divalent metal ions (CaI, CaII, and CaIII). Two metal ions (CaI and CaII) located in the active site are known to be involved in the enzymatic reaction. The third metal ion (CaIII), located near the ${\beta}4-{\alpha}6$ loop region, was newly identified and is thought to be important for the stability of PbXI. Compared with previously determined thermostable and mesophilic XI structures, the ${\beta}1-{\alpha}2$ loop structures near the substrate binding pocket of PbXI were remarkably different. Site-directed mutagenesis studies suggested that the flexible ${\beta}1-{\alpha}2$ loop region is essential for PbXI activity. Our findings provide valuable insights that can be applied in protein engineering to generate low-temperature purpose-specific XI enzymes.

• Journal of Nutrition and Health
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• v.54 no.4
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• pp.335-341
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• 2021

Purpose: Muscle mitochondria play a key role in regulating fatty acid and glucose metabolism. Dysfunction of muscle mitochondria is associated with metabolic diseases such as obesity and type 2 diabetes. Isorhamnetin (ISOR), also known as 3-O-methylquercetin, a quercetin metabolite, is a naturally occurring flavonoid in many plants. This study evaluated the effects of ISOR on the regulation of the mitochondrial function of C2C12 muscle cells. Methods: C2C12 muscle cells were differentiated for 5 days, and then treated in various concentrations of ISOR. Cytotoxicity was determined by assessing cell viability using the water-soluble tetrazolium salt-8 assay principle at different concentrations of ISOR and time points. Levels of the mitochondrial DNA (mtDNA) content and gene expression were measured by quantitative real-time polymerase chain reaction. The citrate synthase (CS) activity was quantified by the enzymatic method. Results: ISOR at a concentration of 10 µM did not show any cytotoxic effects. ISOR increased the mtDNA copy number in a time- or dose-dependent manner. The messenger RNA levels of genes involved in mitochondrial function, such as peroxisome proliferator-activated receptor-γ coactivator-1α, and uncoupling protein 3 were significantly stimulated by the ISOR treatment. The CS activity was also significantly increased in a time- or dose-dependent manner. Conclusion: These results suggest that ISOR enhances the regulation of mitochondrial function, which was at least partially mediated via the stimulation of the mtDNA replication, mitochondrial gene expression, and CS activity in C2C12 muscle cells. Therefore, ISOR may be useful as a potential food ingredient to prevent metabolic diseases-associated muscle mitochondrial dysfunction.

• Journal of Life Science
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• v.16 no.1
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• pp.120-125
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• 2006

To isolate and identify histamine degrading bacteria from Kwamegi, bacteria were screened with restriction media containing histamine. Ten strains were selected through morphological and biochemical identification procedure followed by comparison with DNA sequence of 16 rRNA gene. And also, these strains were confirmed by the histamine degrading assay such as turbidity and enzymatic assay. The results of identification are as followings : Ewingella americana B791, Arthrobacter sp. R45S, Halomonas marisflava, Psychrobacter sp. 9B-7, Bacillus sp. LMC 21002, Psychrohacter cibarius BC-220, Bacillus megaterium KL-197 were identified showing homology of $99\%,\;95\%,\;98\%,\;99\%,\;99\%,\;99\%\;and\;98\%$, respectively. Three strains remain unidentified. Arthrobacter sp. R45S, H. marisflava, Bacillus sp. LMG 21002, B. megaterium KL-197 showed histamine degrading activity, whereas, Psychrobacter sp. 9B-7 only showed weak activity. Three unidentified strains also have histamine degrading activity. In contrast, E. american B791 and p. cibarius JG-220 did not show any significant activity of histamine degradation. The strains isolated from this study showed relatively fast growth rate and histamine degrading rate as compared to those from salted mackerel.

• The korean journal of orthodontics
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• v.25 no.6 s.53
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• pp.697-704
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• 1995

Chicken calvarial bone is known to contain various cell types, but their exact composition is unknown. By characterizing the chicken calvarial bone biochemically, it can be used to study biochemical, histochemical actions of bone cells in general. Calvaria of 18-day-old white leg horn embryo was aseptically dissected and bone cell populations were isolated by sequential enzymatic digestion. Histochemical study for osteoclast-like bone cell. population was performed with tartrate resistant acid phosphatase(TRAP) stain and for osteoblast-like bone cell population, alkaline phosphatase(ALP) stain was performed. Biochemical study for osteoblast-like bone cell population was performed using alkaline phosphatase(ALP) assay. Following conclusions were obtained from this study. 1. TRAP positive multi and mononuclear cells were mostly observed in group I and II, indicating that osteoclast-like bone cell population is mostly found in these groups. 2. All the cultured groups showed almost equal ALP activities and were positive for ALP stain, indicating that osteoblast-like bone cell population is evenly dispersed in all culture groups. 3. Experimental group treated with $1,25(OH)_{2}D_3$ showed increase in ALP activity in contrast to the control group, confirming previous studies that $1,25(OH)_{2}D_3$ increases ALP activities in in vitro bone cultures. 4. Results from von Kossa's stain indicated that in vitro bone formation had occured after 3 weeks of culture with beta-glycero phosphate.

• Journal of Microbiology and Biotechnology
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• v.24 no.9
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• pp.1238-1244
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• 2014

Dephosphocoenzyme A (CoaE) catalyzes the last step in the biosynthesis of the cofactor coenzyme A. In this study, we report the identification and application of CoaE from Stretomyces peucetius ATCC27952. After expression of coaE, the protein was found to have a molecular mass of 28.6 kDa. Purification of the His-tagged fused CoaE protein was done by immobilized metal-affinity chromatography, and then in vitro enzymatic coupling assay was performed. The increasing NADH consumption with time shed light on the phosphorylating activity of CoaE. Furthermore, the overexpression of coaA and coaE independently under the $ermE^*$ promoter in the doxorubicin -producing wild type strain, resulted in 1.4- and 1.5-fold enhancements in doxorubicin production, respectively. In addition, the overexpression of both genes together showed a 2.1-fold increase in doxorubicin production. These results established a positive role for secondary metabolite production from Streptomyces peucetius.

• Journal of The Korean Society of Grassland and Forage Science
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• v.39 no.4
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• pp.298-302
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• 2019

Acidic soil significantly reduces crop productivity mainly due to aluminum (Al) toxicity. Alfalfa (Medicago sativa L.) roots were exposed to aluminum stress (Al₃⁺) in calcium chloride (CaCl₂) solution (pH4.5) and root growth, physiological and antioxidant enzyme responses were investigated. The root growth (length) was significantly inhibited after 48 h of aluminum stress imposition. Histochemical staining with hematoxylin indicated significant accumulation of aluminum in Al stress-treated root tissues. Histochemical assay were also performed to detect superoxide anion, hydrogen peroxide and lipid peroxidation, which were found to be more in root tissues treated with higher aluminum concentrations. The enzymatic activity of CAT, POD and GR in root tissues was slightly increased after Al stress treatment. The result suggests that Al stress alters root growth in alfalfa and induces reactive oxygen species (ROS) production, and demonstrates that antioxidant enzymes involved in detoxification of Al-mediated oxidative stress.

• Journal of Microbiology and Biotechnology
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• v.23 no.7
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• pp.984-992
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• 2013

The entire nucleotide sequence of the xylose reductase (XR) gene in Candida milleri CBS8195 sourdough yeast was determined by degenerate polymerase chain reaction (PCR) and genome walking. The sequence analysis revealed an open-reading frame of 981 bp that encoded 326 amino acids with a predicted molecular mass of 36.7 kDa. The deduced amino acid sequence of XR of C. milleri was 64.7% homologous to that of Kluyveromyces lactis. The cloned XR gene was expressed in Saccharomyces cerevisiae, and the resulting recombinant S. cerevisiae strain produced xylitol from xylose, indicating that the C. milleri XR introduced into S. cerevisiae is functional. An enzymatic activity assay and semiquantitative reverse transcription-PCR revealed that the expression of CmXR was induced by xylose. The GenBank Accession No. for CmXR is KC599203.

• Preventive Nutrition and Food Science
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• v.22 no.3
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• pp.184-190
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• 2017

Matrix metalloproteinases (MMPs) are endopeptidases that take significant roles in extracellular matrix degradation and therefore linked to several complications such as metastasis of cancer progression, oxidative stress, and hepatic fibrosis. Hizikia fusiformis, a brown algae, was reported to possess bioactivities, including but not limited to, antiviral, antimicrobial, and anti-inflammatory partly due to bioactive polysaccharide contents. In this study, the potential of H. fusiformis against cancer cell invasion was evaluated through the MMP inhibitory effect in HT1080 fibrosarcoma cells in vitro. H. fusiformis crude extract was fractionated with organic solvents, $H_2O$, n-BuOH, 85% aqueous MeOH, and n-hexane (n-Hex). The non-toxicity of the fractions was confirmed by MTT assay. All fractions inhibited the enzymatic activities of MMP-2 and MMP-9 according to the gelatin zymography assay. Cell migration was also significantly inhibited by the n-Hex fraction. In addition, both gene and protein expressions of MMP-2 and -9, and tissue inhibitor of MMPs (TIMPs) were evaluated by reverse transcription-polymerase chain reaction and Western blotting, respectively. The fractions suppressed the mRNA and protein levels of MMP-2, MMP-9 while elevating the TIMP-1 and TIMP-2, with the $H_2O$ fraction being the least effective while n-Hex fraction the most. Collectively, the n-Hex fraction from brown algae H. fusiformis could be a potential inhibitor of MMPs, suggesting the presence of various derivatives of polysaccharides in high amounts.