• Biotechnology and Bioprocess Engineering:BBE
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• v.6 no.1
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• pp.37-41
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• 2001

HPLC separation of ionic samples tends to be more complicated and difficult to understand than that of non-ionic compounds. On the other hand, band spacing is much more easily manipulated for ionic than for neutral samples. Ion-suppression RP-HPLC method was used with organic modifier and aqueous buffer solution. In this work, five mononucleotides of cytidine-5-monophosphate (5-CMP) disodium salt, uridine-5-monophosphate disodium salt (5-UMP), guanosine-5-monophosphate disodium salt (5-GMP), inosine-5-monophosphate disodium salt (5-IMP), and adenosine-5-monophosphate disodium salt (5-AMP) were examined. Acetic acid and sodium phosphate were used as buffers, and methanol as an organic modifier. A new relationship between the retention factor and the buffer concentration at a fixed modifier content (5% of methanol) could be expressed by following: K = (k(sub)-1 + k(sub)0 (k(sub)B/k(sub)S)/(1 + (k(sub)B/k(sub)S) C(sub)B(sup)a), where C(sub)B was the concentration of buffer. Using this relationship, the calculated values closely matched the experimental data. The derived relationship showed that as the buffer concentration increased, the retention factor approached a certain value, and this was buffer dependent.

• Biomedical Science Letters
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• v.20 no.2
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• pp.70-76
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• 2014

In this study, we investigated the effect of DMSO, a highly dipolar organic liquid, in collagen ($5{\mu}g/ml$)-stimulated platelet aggregation. DMSO inhibited platelet aggregation at 0.5% by inhibiting production of thromboxane $A_2$ ($TXA_2$) which was associated with blocking cyclooxygenase (COX)-1 activity and $TXA_2$ synthase. In addition, DMSO significantly increased the formation of cyclic adenosine monophosphate (cAMP) from adenosine triphosphate (ATP) and cyclic guanosine monophosphate (cGMP) from guanosine triphosphate (GTP). On the other hand, DMSO (0.1~0.5% concentration) did not affect the LDH release which indicates the cytotoxicity. Based on these results, DMSO has anti-platelet effect by regulation of several platelet signaling pathways, therefore we suggest that DMSO could be a novel strategy on many thrombotic disorders.

• Journal of Microbiology and Biotechnology
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• v.15 no.3
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• pp.573-578
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• 2005

Pyrimidine nucleotide N-ribosidase (pyrimidine 5'-nucleotide phosphoribo(deoxyribo)hydrolase/pyrimidine 5'-nucleotide nucleosidase, EC 3.2.2.10) catalyzes the breakdown of pyrimidine 5'-nucleotide into pyrimidine base and ribose(deoxyribo)-5-phosphate. However, detailed characteristics of the enzyme have not yet been reported. The enzyme was purified to homogeneity 327.9-fold with an overall yield of $6.1\%$ from Pseudomonas oleovorans ATCC 8062. The enzyme catalyzed cytidine monophosphate (CMP) and uridine monophosphate (UMP), but not adenosine monophosphate (AMP) and guanosine monophosphate (GMP). The enzyme optimally metabolized CMP at pH 6.0 and UMP at around 8.5, and the optimum temperature for the overall enzyme reaction was found to be $37^{\circ}C$. The $K_m$ values of the enzyme for CMP (at pH 6.0) and UMP (at pH 8.5) were 1.6 mM and 1.1 mM, respectively. AMP, deoxyCMP, and deoxyUMP were very effective inhibitors of the reaction. Double-reciprocal plots obtained in the absence and in the presence of AMP revealed that this inhibitory effect was of the mixed competitive type with respect to the breakdown of CMP and of the noncompetitive type with respect to the breakdown of UMP. In the presence of AMP, the enzyme followed sigmoid kinetics with respect to each substrate.

• Bulletin of the Korean Chemical Society
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• v.28 no.4
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• pp.601-606
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• 2007

The chromatographic behaviors of nucleotides (inosine 5'-monophosphate, uridine 5'-monophosphate, guanosine 5'-monophosphate, and thymine monophosphate disodium salts) on a C18 column were studied with different types of ionic liquids (ILs) as additives for the mobile phase in reversed-phase liquid chromatography (RPLC). Three ILs, 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIm][BF4]), 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMIm][BF4]), and 1-ethyl-3-methylimidazolium methylsulfate ([EMIm][MS]), were used. Eluents were composed of water and methanol (90/10%, vol) with the addition of 0.5-13.0 mM of ILs. The effects of the concentration of ILs on retention and separation were investigated and discussed. The results showed that the addition of ILs affects the retention and resolution of the tested compounds. Use of 13.0 mM of [BMIm][BF4] as the eluent modifier resulted in a baseline separation of nucleotides without requiring gradient elution. This study demonstrates that ILs can be potentially applied as a mobile phase modifier in RPLC.

• Bulletin of the Korean Chemical Society
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• v.6 no.5
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• pp.270-272
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• 1985

The rate constants of the hydrogen-deuterium exchange of 8-CH groups in 5'-rAMP and 5'-GMP were measured by laser Raman spectroscopy. The Arrhenius activation energies calculated from the rate constants measured as a function of temperature were similar for both compounds. However, the effects of pD on exchange rate constants were different for the two compounds. Our kinetic data support the exchange reaction mechanism involving an ylide type intermediate.

• Journal of the East Asian Society of Dietary Life
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• v.11 no.3
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• pp.196-203
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• 2001

This study was conducted to provide basic data for the development of natural seasoning. The quality chatacteristics of water exacts from Pleurotus ostreatus and Lentinus edodes were determind. Also, savory taste, fragrance, color and overall preference was evaluated. The preference test on the seasonings prepared from Pleurotus ostreatus and Lentinus edodes with the addition of sea tangle was also performed. The crude protein content of dried, Lentinus edodes and Pleurotur ostreatus was 20.4% and 30.4% respectively. The total organic acid contents were higher in Plourotus ostreatus than in Lentinus edodes extracts. The total free amino acid adn total nucleotide contents were higher in Pleurotus ostreatus than in Lentinus edodes extracts. Three nucleotide, adenosine monophosphate(AMP) , guanosine monophosphate(GMP), xanthine monophosphate(XMP) were found in mushroom seasonings while inosine monophosphate(IMP) was not detected. Pleurotus ostreatus extract showed higher score in savory taste and overall acceptability than Lentinus edodes extract, Pleurotur ostreatus seasoning added with 1% sea tangle and Lentinus edodes seasoning added with 1.5% sea tangle were rated as high in overall quality In a sensory test of foods cooked with mushroom seasoning. It was shown that panels in their twenties well used to the taste of monosodium glutamate while the people in their thirties preferred the specific flavor of the mushroom seasoning.

• Food Science of Animal Resources
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• v.39 no.1
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• pp.93-101
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• 2019

Nucleotides play important roles in numerous intracellular biochemical processes and are used in infant formulas and other dairy products. However, domestic analytical methods for assessing nucleotide content in products have not yet been established, and therefore, methods for determining nucleotide content are urgently required. A rapid and simple analytical method for determining the content of five types of nucleotides in dairy products was improved using solid phase extraction clean-up and high-performance liquid chromatography with diode array detector. The extraction solvent used in the AOAC method was not well dissolved and was changed to hydrophilic EDTA-Na. In addition, the results obtained using the isocratic elution method and a single wavelength were similar to those obtained using the AOAC method, and the time taken for analysis was shortened from 40 min to 25 min. The process of method validation revealed the following parameters: accuracy (84.69%-102.72%), precision (1.51%-6.82%), linearity (0.999), and limit of detection (cytidine 5'-monophosphate, 0.09 mg/L; uridine 5'-monophosphate, 0.11 mg/L; adenosine 5'-monophosphate, 0.12 mg/L; guanosine 5'-monophosphate, 0.11 mg/L; and inosine 5'-monophosphate, 0.14 mg/L). The method was also used to determine the nucleotide concentration in 25 samples (infant formulas, 1.99-29.39 mg/100 g; and cow milk, 0.28-0.83 mg/100 g). The newly improved method was appropriate for analyzing nucleotides in infant formulas and other dairy products faster when compared to conventional methods.

• The Korean Journal of Physiology and Pharmacology
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• v.8 no.2
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• pp.95-100
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• 2004

Ischemic preconditioning (IPC) has been accepted as a heart protection phenomenon against ischemia and reperfusion (I/R) injury. The activation of ATP-sensitive potassium $(K_{ATP})$ channels and the release of myocardial nitric oxide (NO) induced by IPC were demonstrated as the triggers or mediators of IPC. A common action mechanism of NO is a direct or indirect increase in tissue cGMP content. Furthermore, cGMP has also been shown to contribute cardiac protective effect to reduce heart I/R-induced infarction. The present investigation tested the hypothesis that $K_{ATP}$ channels attenuate DNA strand breaks and oxidative damage in an in vitro model of I/R utilizing rat ventricular myocytes. We estimated DNA strand breaks and oxidative damage by mean of single cell gel electrophoresis with endonuclease III cutting sites (comet assay). In the I/R model, the level of DNA damage increased massively. Preconditioning with a single 5-min anoxia, diazoxide $(100\;{\mu}M)$, SNAP $(300\;{\mu}M)$ and 8-(4-Chlorophenylthio)-guanosine-3',5'-cyclic monophosphate (8-pCPT-cGMP) $(100\;{\mu}M)$ followed by 15 min reoxygenation reduced DNA damage level against subsequent 30 min anoxia and 60 min reoxygenation. These protective effects were blocked by the concomitant presence of glibenclamide $(50\;{\mu}M)$, 5-hydroxydecanoate (5-HD) $(100\;{\mu}M)$ and 8-(4-Chlorophenylthio)-guanosine-3',5'-cyclic monophosphate, Rp-isomer (Rp-8-pCPT-cGMP) $(100\;{\mu}M)$. These results suggest that NO-cGMP-protein kinase G (PKG) pathway contributes to cardioprotective effect of $K_{ATP}$ channels in rat ventricular myocytes.

• Microbiology and Biotechnology Letters
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• v.7 no.3
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• pp.127-133
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• 1979

By the treatment of several mutagens, a number of 5'-guanylic acid producing mutants from 5'-xan-thylic acid were obtained from Brevibacterium ammoniagenes ATCC 6871. The indispensensable genetic-characters of the mutants were adenine requirement, lack of GMP-reductase and mutation to adenosine resistance from adenosine sensitiveness. Main product from 5'-xanthylic acirl by strain BA-17-2 was 5'-guanulic acid, and was isolated in a crystalline form by the use of anion exchange resin, Duolite 102 D. The isolated crystalline was identified as 5'-guanylic acid by means of paper chromatography, ultrav-iolet absorption spectra, and infrared absorption spectrum.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.12
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• pp.298-305
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• 2019

Cudrania tricuspidata has been reported to have many biological activities, including anti-inflammatory, anti-cancer, and antioxidant properties. However, the effects of C. tricuspidata root extract (CTE) on human platelet aggregation induced by collagen as well as the signaling pathways involved remain unknown. In the present study, we investigated the effect of CTE on human platelets. CTE inhibited platelet aggregation via down-regulation of thromboxane A₂ (TXA₂) by blocking cyclooxygenase-1 (COX-1) activity and intracellular Ca²⁺ mobilization in collagen-induced platelets. CTE also reduced the phosphorylation of phospholipase C (PLC) γ2 and syk. CTE regulated platelet aggregation via cyclic guanosine monophosphate (cGMP)-dependent phosphorylation of vasodilator-stimulated phosphoprotein (VASP) Ser²³⁹. In addition, administration of CTE (50 and 100 mg/kg) significantly reduced hyper-aggregated platelet aggregation by collagen (5 ㎍/mL) without hepatotoxicity in HFD (high fat diet)-fed rats. Taken together, these results suggest that CTE has anti-platelet effects both in vitro and in vivo. Therefore, CTE may be an effective therapeutic and preventive agent for cardiovascular disease, and is a safe and natural product.