• Bulletin of the Korean Chemical Society
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• v.30 no.12
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• pp.2949-2958
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• 2009

Massive deguanylation of guanine based-nucleosides induced by halogenated alkanes at the physiological condition have been observed. For the study of deguanylation effects by the different substituents and/or functionality in halogenated alkanes, diverse kinds of halogenated alkanes were incubated with guanine based-nucleosides (ddG, dG and guanosine) for 48 h at the physiological condition (pH 7.4, 37$^{\circ}C$), which were analyzed by HPLC and further confirmed by LC-MS. Among the sixteen different halogenated alkanes, we observed massive deguanylation of nucleosides by 2-bromo-2-methylpropane, 2,3-dibromopropene, 2-bromopropane, bromoethane and 2-iodopropane. The order of deguanylation rate was highest in 2-bromo-2-methylpropane followed by 2,3-dibromopropene, 2-bromopropane, bromoethane and 2-iodopropane. In addition, time and dose response relationship of deguanylation in guanine basednucleosides induced by 2-bromo-2-methylpropane, 2,3-dibromopropene, 2-bromopropane, bromoethane and 2-iodopropane at the physiological condition were investigated. Deguanylation of calf thymus DNA induced by halogenated alkanes was also investigated. These results suggest that the toxic effect of certain halogenated alkanes might be from the depurination of nucleosides.

• Bulletin of the Korean Chemical Society
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• v.12 no.2
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• pp.196-199
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• 1991

Attempts were made to develop new protecting groups for 1,6-lactam function of 2-N-acyl guanine in oligodeoxyribonucleotide synthesis. Several acyl groups, aryl groups, and carbamoyl groups were tested. Dimethylcarbamoyl and phenylacetyl groups are shown to be a good combination for guanine residue. 6-O-Di-methylcarbamoyl-2-N-pheylacetyl-2'-deoxy guanosine have been successfully used in the synthesis of d[AAGCTT], which is Hind Ⅲ recognition sequence.

• Bulletin of the Korean Chemical Society
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• v.33 no.12
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• pp.4265-4266
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• 2012

• Korean Journal of Food Science and Technology
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• v.13 no.2
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• pp.121-126
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• 1981

An adenine-guanine doubless and $\beta$-alanine requiring mutant, D-1550-40, which had been derived from Brevibacterium ammoniagenes ATCC 6872, produced a copious amount of xanthosine-5'-monophosphate (XMP). The optimum concentration of adenine and guanine for maximal accumulation of XMP was about 75 ml/l and 100 ml/l for growth. Concentrations higher than 100 mg/l of adenine and guanine inhibited cell growth and XMP accumulation strongly. The inhibition, however, could be recovered by adding $100{\mu}g$ of biotin per liter or 0.3% of casamino acids to the culture solution. High concentrations of phosphate and magnesium salts (1.0 to 1.5%(w/v) in media) were found to be indispensable for XMP accumulation, and the presence of manganese in the culture medium stimulated both growth of cells and accumulation of XMP leaving 5'-inosinic acid unaffected. The maximal accumulation of XMP reached to 60.5 mg/l after 4 days of fermentation which had been started with a medium containing 100 mg of adenine-guanine, 5 mg of $MnSO_4{\cdot}H_2O$ and $100{\mu}g$ of biotin per liter. The specific XMP synthesis(mg of XMP/mg of cells) was increased with the increase of the cell growth rate.

• Journal of the Korean Chemical Society
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• v.49 no.4
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• pp.343-348
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• 2005

• Microbiology and Biotechnology Letters
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• v.14 no.6
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• pp.441-446
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• 1986

Some properties of extracellular guanine deaminase produced by Pseudomonas synxantha A3 were studied. The enzyme was stable at pH 6.5-7.5 and generally stable when it was incubated at 4$0^{\circ}C$ for 10 minutes but inactivated gradually above 4$0^{\circ}C$. When the enzyme in 0.2M potassium phosphate (pH 8.0) was stored at room temperature, it was stable for thirty days. Alcohols and acetone were not effective for the eyzyme stability. The optimum pH and temperature for the enzyme activity were around pH 7.0-8.0 and 5$0^{\circ}C$, respectively. The enzyme was inhibited by 1mM of Hg$^{++}$, Ag$^+$ and Li$^+$ and by 0.1mM of Ag$^+$ with about 50% loss of activity. The enzyme inhibited by Li$^+$ was reactivated by EDTA. 1 mM of pentachlorophenol and p-CMB inactivated the enzyme with 50% and 40% loss of activity, respectively. The enzyme inactivated by p-CMB was reactivated by glutathione.

• Korean Chemical Engineering Research
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• v.48 no.1
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• pp.88-92
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• 2010

DNA structure studies attract many interests in pharmaceutical, biochemical and medical disciplines. Among them, base pairs play a vital role in biological information transfer. Therefore, they need to be analyzed in various ways and the pair of guaninine and cytosine is the present analytical object. Separation of guanine and cytosine was researched by Aspen chromatography simulator and HPLC(High Performance Liquid Chromatography) experiments. Aspen chromatography simulation resulted in various chromatograms with changes of sample concentration, eluent flow rate and number of plate. The resolutions and yields of guanine and cytosine were calculated to obtain a best separation condition. $C_{18}$ HPLC column and water/methanol/acetic acid mixture(90/10/0.2) were used for separation of guanine and cytosine. HPLC parameters(resolution and number of theoretical plate) were calculated under different flow rates and sample concentrations. Aspen chromatography simulation and HPLC experimental results were compared with fair agreement.

• Archives of Pharmacal Research
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• v.25 no.1
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• pp.39-44
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• 2002

Recently, we have reported that 2-bromopropane might have an immunotoxic potential in rats when exposed for 28 days. In the present studies, the possibility of 2i-deoxyguanosine abduct formation by 2- bromopropane was investigated in vitro to elucidate molecular mechanism of 2-bromopropane-induced immunosuppression. $N^7-Guanine adduct$ of 2'-bromopropane (i.e., $N^7-isopropyl$ guanine) was chemically synthesized and structurally characterized by analysis of UV,$^1H-NMR,{\;}^{13}C-NMR$, COSY and fast atom bombardment mass spectrometry to use as a reference material. Incubation of 2'-deoxyguanosine with an excess amount of 2-bromopropane in PBS buffer solution, pH 7.4, at $37^{\circ}C$ for 16 h, followed by a thermal hydrolysis, produced a detectable amount of $N^7-isopropyl$ guanine by an HPLC and UV analysis. The present results suggest that 2-bromopropane might form a DNA adduct in $N^7-position$ of 2'-deoxyguanosine at 3 Physiological condition.

• Mass Spectrometry Letters
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• v.2 no.3
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• pp.73-75
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• 2011

In the collisionally-activated dissociation of the proton-bound cluster ions of DNA base guanine (G) and cytosine (C), $G{\bullet}{\bullet}H^+{\bullet}{\bullet}C$, the abundance of [$CH^+$] ions was found to be higher than that of [$GH^+$] despite the fact that G has a higher proton affinity than C. This unexpected observation seems to demonstrate another example that the simple kinetic method scheme does not work. We suggest that a kinetic factor or detailed dynamics governing the proton transfer and dissociation should be carefully considered in the applications of the kinetic method to the proton affinity measurements.

• BMB Reports
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• v.37 no.2
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• pp.260-267
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• 2004

Transducin (T), the heterotrimeric guanine nucleotide binding protein in rod outer segments, serves as an intermediary between the receptor protein, rhodopsin, and the effector protein, cGMP phosphodiesterase. Labeling of T with dansyl chloride (DnsCl) inhibited its light-dependent guanine nucleotide binding activity. Conversely, DnsCl had no effect on the functionality of rhodopsin. Approximately 2-3 mol of DnsCl were incorporated per mole of T. Since fluoroaluminate was capable of activating DnsCl-modified T, this lysine-specific labeling compound did not affect the guanine nucleotide-binding pocket of T. However, the labeling of T with DnsCl hindered its binding to photoexcited rhodopsin, as shown by sedimentation experiments. Additionally, rhodopsin completely protected against the DnsCl inactivation of T. These results demonstrated the existence of functional lysines on T that are located in the proximity of the interaction site with the photoreceptor protein.