• Korean Journal of Microbiology
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• v.29 no.5
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• pp.270-277
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• 1991

A mutational alteration in the signal sequence of ribose-binding protein (RBP) of Escherichia coli, rbsB103, completely blocks the export of the protein to the periplasm. Intragenic suppressors for this mutation have been selected on minimal medium with ribose as a sole carbon source. Six suppressor mutations were characterized in detail and were found to have single amino acid wubstitution in the mature portion of RBP, which resulted in the mobility shift of the proteins on SDS polyacrylamide gel. Amino acid changes of these suppressors were localized in several peptides which are packed to form the N terminal domain of typical bilobate conformation of RBP. The involvement of SecB, a molecular chaperone, was investigated in the suppression of signal sequence mutation. Translocation efficency was found to be increased by the presence of SecB for all suppressors. It is likely that the folding characteristics of RBP altered by the suppressor mutations affect the affinity of interaction between SecB and RBP.

• Journal of the Korean Chemical Society
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• v.38 no.11
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• pp.783-784
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• 1994

• The Korean Journal of Zoology
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• v.26 no.3
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• pp.171-179
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• 1983

Amounts of DNA single strand breaks and unscheduled DNA synthesis in CHO cells exposed to MMS were increased in the presence of 3-aminobenzamide, a potent inhibitor of poly (ADP-ribose) polymerase. However, those in cells irradiated with UV-light were decreased. These results suggest that poly (ADP-ribose) polymerase acts negatively on the MMS-induced base excision repair but positively on the UV-induced nucleotide excision repair. In the combined treatment with MMS and UV-light in the presence of this inhibitor, amounts of strand breaks were just the same as those in the absence of the inhibitor. But those of unscheduled DNA synthesis were increased up to the amount induced by UV-light alone. These results may suggest that poly (ADP-ribose) polymerase affects the incision step of excision repair induced by MMS and UV-light independently, and that it may potentiate the complete cleaving of UV-induced pyrimidine dimers possibly by the repair enzymes which might have been partially inactivated by MMS.

• Microbiology and Biotechnology Letters
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• v.33 no.2
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• pp.106-111
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• 2005

To investigate the substrate variety of a putative non-metal dependent isomerase, the tagatose-6-phosphate isomerase (E.C. 5.3.1.26) structural genes (lacB; 510bp and lacA; 430bp) of Staphylococcus aureus were subcloned and co-expressed. Based on the substrate configuration, various aldoses were surveyed for substrate of ketose isomerization. Among the 10 aldoses tested, D-ribose and D-allose were isomerized by the enzyme. The subunit A and B showed more than $95\%$ activity for D-ribose and $75\%$ for D-allose in the presence of 1mM EDTA compared with non-EDTA conditions, which implying tagatose-6-phosphate isomerase is a non-metal dependent isomerase. Each of subunit A or subunit B alone showed no activity for any of the substrates tested. The affinity constant ($K_m$) of tagatose-6-phosphate isomerase against D-ribose and D-allose were 26 mM and 142 mM, respectively.

• Archives of Pharmacal Research
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• v.26 no.10
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• pp.826-831
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• 2003

ADP-ribose pyrophosphatase (ADPRase) hydrolyzes ADP-ribose (ADPR) into AMP and ribose-5'-phosphate. It is classified into two groups, $Mg^{2+}$-dependent and $Mg^{2+}$-independent ADPRase, depending on its $Mg^{2+}$requirement. Here, we purified $Mg^{2+}$-dependent ADPRase from rabbit liver and examined what factors affect $Mg^{2+}$ requirement. The purified enzyme showed a single band with the molecular weight of 34 kDa on SDS-PAGE both in the presence and absence of 2-mercaptoethanol. The molecular weight of the native enzyme calculated by gel filtration was 68 kDa, indicating that ADPRase is a dimer made up of two identical subunits. $Mg^{2+}$-dependent ADPRase with the highest ADPR affinity had a $K_m$ of 160$\pm$10 $\mu$M and a pH optimum of around pH 9.5. Treatment of the purified ADPRase with heated cytosol fractions at 37$^{\circ}C$ for 3 h caused some changes in the chemical properties of the enzyme, including an increase in molecular weight, a decrease in solubility, and a loss of $Mg^{2+}$-dependency. The molecular weight of the cytosol-treated ADPRase measured by gel filtration was over 420 kDa, suggesting, for the first time, that ADPRase could be polymerized by undefined cytoplasmic factors, and that polymerization is accompanied by changes in the solubility and metal ion dependency of the enzyme.

• Journal of Life Science
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• v.21 no.5
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• pp.729-733
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• 2011

The purpose of this study was to examine the effect of D-ribose supplementation on the changes of blood fatigue substances (lactate, ammonia, phosphate and hypoxanthine) after maximal exercise performance in college male students. The experimental trials of each subject were divided into the following conditions: placebo supplement trial and D-ribose supplement trial. The subjects exercised using a Concept II Indoor rowing ergometer for 2,000 m Single Skull event. The subjects ingested 200 mg/kg of D-ribose after breakfast, lunch, dinner, as well as thirty minutes before exercising, for six days. Blood fatigue substances were continuously measured before exercise, immediately after exercise, and thirty minutes after exercise. The results indicated a significant difference in blood phosphate and hypoxanthine levels between the two experimental trials in the 30 minute recovery period (p<0.05). However, there were no significant differences in blood lactate and phosphate levels between the two experimental trials. The results of our study suggest that D-ribose supplementation during maximal rowing exercise for 7~8 minutes may contribute to the improvement of metabolic responses as a beneficial ergogenic aid accelerating fatigue clearance.

• Korean Journal of Soil Science and Fertilizer
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• v.22 no.3
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• pp.191-196
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• 1989

Monosaccharide content of four forest soils were analyzed. Two soils under coniferous forest trees and another two under duciduous forest trees of Mts. Zeombong and Odae in Kangweon-Do were sampled from the surface horizon down into the subhorizons. 1. The largest amount of monosaccharide is found in the surface organic horizon of each soil and with increasing depth the amount decreases as might be expected considering total organic matter content. 2. Hexoses (galactose, glucose, mannose) predominate over pentoses (arabinose, ribose, xylose) and deoxyhexoses (fucose, rhamnose), the latter being in the smallest amount. Glucose is the most abundant monosaccharide in all samples regardless of vegetation of soil or depth. In general the content of each monosaccharide follows the order of glucose > manrtose > galactose > arabinose > xylose > rhamnose > fucose > ribose. 3. Very little amount of ribose is present even in organic horizons of coniferous forest soils. In samples taken from deciduous forest soils ribose is virtually absent. 4. The relative proportion of monosacchaiide to the total soil organic matter decreases with increasing depth, which may be resulted from the effect of prolonged humification. The total monosaccharide in the organic surface layer amounts to 27-50% of the total organic carbon or 15.7-29% of the total organic matter. Hexoses alone take the largest share of 20-38% of the carbon, or 12-22% of the organic matter.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.1
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• pp.62-69
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• 2009

Maillard reaction products (MRPs) were produced from aqueous solution of various sugars with defatted hydrolyzed soybean protein (DFHSP) with different temperatures and pressures. Physicochemical properties of MRPs were investigated; also, DPPH and hydroxyl radical scavenging activity and sensory properties were evaluated. MRPs from ribose and DFHSP had the highest reactivity with larger pH reduce, higher browning index increase and higher antioxidant activity than other MRPs from other sugars. The antioxidant activities were increased with increasing temperatures and pressures of reaction. The highest antioxidant activity and sensory preference were obtained from MRPs with ribose at $140^{\circ}C$ with 2.8 kg/$cm^2$ for 30 mins.

• Korean Journal of Microbiology
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• v.26 no.4
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• pp.283-290
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• 1988

A spontaneous revertant of mutation rbsB103 that is ribose taxis-positive was characterized. This revertant was found to be export-competent in the export of ribose-binding protein shown by the disappearance of accumulated mutant precursor protein and the export of mature ribose-binding protein to the periplasm. The reversional change was shown to be in the region of risB gene that codes for the amino terminal portion of ribose-binding protein. Analysis by high-performance liquid chromatography of peptide patterns of ribose-binding proteins confirmed the relationship between the wild-type and the revertant proteins as shown for the mutant previously (Iida et al., 1985). When the processing rate of presursor proteins from the wild type and the revertant strain in vivo was compared by pulse-chase experiment, it was found that processing is less efficient than normal in the revertant. Purified mature proteins from both wild-type and revertant were subjected to amino acid sequencing. The results confirmed the amino acid changes deduced from the DNA sequencing and showed that processing of the revertant precursor occured in the correct position even though there are two different amino acids present in the signal sequence.

• BMB Reports
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• v.48 no.6
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• pp.354-359
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• 2015

Vascular smooth muscle cells (VSMCs) undergo death during atherosclerosis, a widespread cardiovascular disease. Recent studies suggest that oxidative damage occurs in VSMCs and induces atherosclerosis. Here, we analyzed oxidative damage repair in VSMCs and found that VSMCs are hypersensitive to oxidative damage. Further analysis showed that oxidative damage repair in VSMCs is suppressed by a low level of poly (ADP-ribosyl)ation (PARylation), a key post-translational modification in oxidative damage repair. The low level of PARylation is not caused by the lack of PARP-1, the major poly(ADP-ribose) polymerase activated by oxidative damage. Instead, the expression of poly(ADP-ribose) glycohydrolase, PARG, the enzyme hydrolyzing poly(ADP-ribose), is significantly higher in VSMCs than that in the control cells. Using PARG inhibitor to suppress PARG activity facilitates oxidative damage-induced PARylation as well as DNA damage repair. Thus, our study demonstrates a novel molecular mechanism for oxidative damage-induced VSMCs death. This study also identifies the use of PARG inhibitors as a potential treatment for atherosclerosis. [BMB Reports 2015; 48(6): 354-359]