• Bulletin of the Korean Chemical Society
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• v.31 no.2
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• pp.464-466
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• 2010

• The Korean Journal of Physiology and Pharmacology
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• v.2 no.5
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• pp.637-644
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• 1998

Previously, we have isolated authentic bombesin and another bombesin like peptide named bombesin like immunoreactivity (BLI)-K2 from the skin of Korean fire-bellied toad, Bombina orientalis. In the present study, we have newly purified three heterogeneous forms of BLI named BLI-K3, BLI-K4, and BLI-K5 from side fractions obtained in previous isolation of bombesin like peptide. The BLIs were separated into five peaks on a column of $C_{18}$ preparative HPLC. Among them, three minor peaks containing BLI-K3, K4, and K5 were purified by means of sequential chromatography on the columns of SP cation exchange HPLC and $C_{18}$ reverse phase HPLC. The purified BLI-K3 and K4 showed high binding affinity to an anti-bombesin serum (LBE 2G-2) with binding potency of 72 and 95%, respectively, relative to that of bombesin. However, they did not possess any distinctive biological activity of bombesin like peptide. On the contrary, the biological activity of BLI-K5 was similar to that of bombesin but its binding affinity to an anti-bombesin serum was low. The results indicate that three heterogeneous forms of BLI were coexpressed with bombesin and BLI-K2 in the skin of B. orientalis. All forms of the purified BLI in the present study were immunologically active but only BLI-K5 possessed the distinctive biological activity of bombesin like peptide.

• The Korean Journal of Nuclear Medicine
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• v.27 no.1
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• pp.28-34
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• 1993

Using in vitro autoradiography with a digital autoradiography system and radioreceptor assay, the distribution and the binding characteristics of the muscarinic cholinergic receptors (mAChR) were studied in regions of rat brain. Radioreceptor assay revealed that mAChR could be measured with saturation binding assay in the brain and heart homogenates: No difference in Kd or Bmax of the brain or heart was found between the normal Wistar rats and SHR rats. Specific binding of $^3H$ quinuclidinyl benzilate (QNB) increased and saturation was reached by 2 hours after incubation with slide-mounted brain tissue. The distribution of mAChR was heterogeneous along the fields of brain. Affinity (Kd) of mAChR was not different significantly among cortex, hippocampus and caudate-putamen. No difference was found between normal rats and SHR strain. More receptors (Bmax) were found in the cortex and hippocampus than in the caudate-putamen in normal rats. More receptors were found in the cortex and caudate-putamen in SHR rats than in normal rats. Radioreceptor assay and digital autoradiographic analysis of affinity and number of mAChR gave the same results. With the above findings, we concluded that we could use digital autoradiographic system with $^3H$-QNB in the characterization of mAChR of rats and that the cortex and caudate-putamen of SHR strain rats have more receptors than those of normal rats.

• Journal of Microbiology
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• v.35 no.4
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• pp.327-333
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• 1997

Although extensively characterized in human cells, no heterogeneous nuclear ribonucleoprotein(hnRNP) has been found in the fission yeast Schizosaccharomyces pombe which is amenable to genetic studies and more similar to mammals than Saccharomyces cerevisiae is in terms of RNA processing. As a first step to characterize hnRNPs from S. pombe, attempt was made to find human hnRNP A1 homologs from S. pombe. The RNA molecule (A1 winner) containing the consensus high-affinity hnRNP A1 binding site (UAGGGA/U) was synthesized in vitro and used in an ultraviolet(UV) light-induced protein-RNA cross-linking assay. A number of S, pombe proteins bound to the A1 winner RNA. An approximately 50-kDa protein(p50) cross-linked more efficiently to the A1 winner RNA than other proteins. The p50 protein did not cross-link to a nonspecific RNA, but rather to the A1-5’ SS RNA in which the consensus 5’ splice junction sites of S. pombe introns were abolished. This suggests that the p50 protein, however, did not bind to the single-stranded DNA to shich the human hnRNP A1 could bind and be eluted with 0.5M NaCl. Further analysis should reveal more features of this RNA-binding protein.

• Molecules and Cells
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• v.42 no.6
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• pp.495-500
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• 2019

Brain cytoplasmic 200 RNA (BC200 RNA), originally identified as a neuron-specific non-coding RNA, is also observed in various cancer cells that originate from non-neural cells. Studies have revealed diverse functions of BC200 RNA in cancer cells. Accordingly, we hypothesized that BC200 RNA might be modified in cancer cells to generate cancerous BC200 RNA responsible for its cancer-specific functions. Here, we report that BC200 RNA sequences are highly heterogeneous in cancer cells by virtue of multiple adenine nucleotide insertions in the internal A-rich region. The insertion of adenine nucleotides enhances BC200 RNA-mediated translation inhibition, possibly by increasing the binding affinity of BC200 RNA for eIF4A (eukaryotic translation initiation factor 4A).

• Korean Journal of Materials Research
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• v.28 no.6
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• pp.365-369
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• 2018

We perform density functional theory calculations to study the CO and $O_2$ adsorption chemistry of Pt@X core@shell bimetallic nanoparticles (X = Pd, Rh, Ru, Au, or Ag). To prevent CO-poisoning of Pt nanoparticles, we introduce a Pt@X core-shell nanoparticle model that is composed of exposed surface sites of Pt and facets of X alloying element. We find that Pt@Pd, Pt@Rh, Pt@Ru, and Pt@Ag nanoparticles spatially bind CO and $O_2$, separately, on Pt and X, respectively. Particularly, Pt@Ag nanoparticles show the most well-balanced CO and $O_2$ binding energy values, which are required for facile CO oxidation. On the other hand, the $O_2$ binding energies of Pt@Pd, Pt@Ru, and Pt@Rh nanoparticles are too strong to catalyze further CO oxidation because of the strong oxygen affinity of Pd, Ru, and Rh. The Au shell of Pt@Au nanoparticles preferentially bond CO rather than $O_2$. From a catalysis design perspective, we believe that Pt@Ag is a better-performing Pt-based CO-tolerant CO oxidation catalyst.

• Journal of Yeungnam Medical Science
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• v.14 no.1
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• pp.53-66
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• 1997

Insulin resistance is a prominent feature of diabetic state and has heterogeneous nature. However, the pathogenetic sequence of events leading to the emergence of the defect in insulin action remains controversial. It is well-known that prolonged hyperglycemia and hyperinsulinemia are one of the causes of development of insulin resistance, but both hyperglycemia and hyperinsulinemia stimulate glucose uptake in peripheral tissue. Therefore, it is hypothesized that insulin resistance may be generated by a kind of protective mechanism preventing cellular hypertrophy. In this study, to evaluate whether the acutely increased glucose uptake inhibits further glucose transport stimulated by insulin, insulin sensitivity was measured after preloaded glucose infusion for 2 hours at various conditions in rats. And also, to evaluate the mechanism of decreased insulin sensitivity, insulin receptor binding affinity and glucose transporter 4 (GLUT4) protein of plasma membrane of gastrocnemius muscle were assayed after hyperinsulinemic euglycemic clamp studies. Experimental animals were divided into five groups according to conditions of preloaded glucose infusion: group I, basal insulin ($14{\pm}1.9{\mu}U/ml$) and basal glucose ($75{\pm}0.7mg/dl$), by normal saline infusion; group II, normal insulin ($33{\pm}3.8{\mu}U/ml$) and hyperglycemia ($207{\pm}6.3mg/dl$), by somatostatin and glucose infusion; group III, hyperinsulinemia ($134{\pm}34.8{\mu}U/ml$) and hyperglycemia ($204{\pm}4.6mg/dl$), by glucose infusion; group IV, supramaximal insulin ($5006{\pm}396.1{\mu}U/ml$) and euglycemia ($l00{\pm}2.2mg/dl$), by insulin and glucose infusion; group V, supramaximal insulin ($4813{\pm}687.9{\mu}U/ml$) and hyperglycemia ($233{\pm}3.1mg/dl$), by insulin and glucose infusion. Insulin sensitivity was assessed with hyperinsulinemic euglycemic clamp technique. The amounts of preloaded glucose infusion(gm/kg) were $1.88{\pm}0.151$ in group II, $2.69{\pm}0.239$ in group III, $3.54{\pm}0.198$ in group IV, and $4.32{\pm}0.621$ in group V. Disappearance rates of glucose (Rd, mg/kg/min) at steady state of hyperinsulinemic euglycemic clamp studies were $16.9{\pm}3.88$ in group I, $13.5{\pm}1.05$ in group II, $11.2{\pm}1.17$ in group III, $13.2{\pm}2.05$ in group IV, and $10.4{\pm}1.01$ in group V. A negative correlation was observed between amount of preloaded glucose and Rd (r=-0.701, p<0.001) when all studies were combined. Insulin receptor binding affinity and content of GLUT4 were not significantly different in all experimental groups. These results suggest that increased glucose uptake may inhibit further glucose transport and lead to decreased insulin sensitivity.