• Journal of Radiation Protection and Research
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• v.5 no.1
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• pp.32-35
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• 1980

A number of chemical compounds that modify radiation effects are reviewed, with brief report of our own experiments on radioprotective effect of some vasoconstrictive agents and 5-Thio-D-Glucose. Sulfhydryl compounds(-SH group) and some pharmacologic compounds such as CNS depresants, vasoconstrictive agents and autonomic drugs are known to have radioprotective effect in experimental research and in limitted clinical study, whereas oxygen, hallogenated pyrimidines and metronidazole, etc. have radiosensitizing effect. Author experimentally observed some radioprotective effects of angiotensin II, a strong vasoconstrictor, and 5-Thio-D-glucose in mice.

• Journal of the Korean Society of Tobacco Science
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• v.21 no.1
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• pp.49-56
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• 1999

Classification of esterase isozymes of the apterous green peach aphids (Myzus persicae Sulzer) collected in tobacco fields were investigated by the native polyacrylamide gel electrophoresis (PAGE). A total of twelve esterase bands were identified in adult apterous aphid, and the difference of enzyme band activity in the clones was observed at the first and second bands group. Esterases of green peach aphids reacted with specific substrate were more stained $\alpha$-naphthyl acetate than $\alpha$-naphthyl propionate, and $\alpha$-naphthyl acetate more than $\beta$-naphthyl acetate. Twelve esterases on the basis of inhibition by the three types of inhibitors (organophosphates: 2.5$\times$10$^{-3}$ M paraoxon, 4$\times$10$^{-3}$ M DFP; eserine sulfate : 2$\times$10$^{-3}$ M eserin; sulfhydryl reagents: 2$\times$10$^{-3}$ M p-HMB) were classified into three class, namely, cholinesterase (ChE) I, II, carboxylesterase (CE) and arylesterase (ArE), and these classes contained 3, 4, 3 and 2 isozymes, respectively.

• The Korean Journal of Pharmacology
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• v.32 no.2
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• pp.169-175
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• 1996

The reactivity of the sulfhydryl (thiol) group of homocysteine has been associated with an Increased risk of atherosclerosis, thrombosis and stroke. Thiols also react with nitric oxide (NO, an endothelium-derived relaxing factor (EDRF) ), forming S-nitrosothiols that have been reported to have potent vasodilatory and antiplatelet effects and been expected to decrease adverse vascular effects of homocysteine. The present study was aimed to Investigate whether the S-nitrosation of homocysteine modulates the neurotoxic effects of homocysteine. An 18 hour-exposure of cultured rat cortical neurons to homocysteine ( >1 mM) resulted in a significant neuronal cell death. At comparable concentrations ( <10 mM), however, S-nitrosohomocysteine did not induce neuronal cell death. Furthermore, S-nitrosohomocysteirle partially blocked NMDA-mediated neurotoxicity. S-nitrosohomocysteine also decreased NMDA-mediated increases in intracellular calcium concentration. The present data indicate that in brain nitric oxide produced from neuronal and nonneuronal cells can modulate the potential, adverse properties of homocysteine.

• Proceedings of the Korean Biophysical Society Conference
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• 2002.06b
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• pp.34-34
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• 2002

Oxidative stress has been considered as a major cause of inducing cell damage, but it is recently recognized that mild oxidative stress or receptor-mediated production of ROS contributes to the regulation of various cellular functions. Several ion channels, such as L-type $Ca^{2＋}$ channels and $Ca^{2＋}$-activated $K^{＋}$ channels, have been shown to be regulated by oxidation of thiol group in their structure, and are suggested to be involved in ROS-sensitive cellular signaling.(omitted)

• Microbiology and Biotechnology Letters
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• v.1 no.2
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• pp.99-104
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• 1973

A study on the active center of the acid protease from Penicillium sp. was conducted, and also the milk clotting activity of acid prorease was measured. 1. PCMB failed to influence the proteolytic activity of acid protease, indicating that a reactive sulfhydryl group is not required for the enzymatic activity. 2. $\varepsilon$-amino caproic acid did not show any inhibitory effect on tile proteolytic activity of acid protease. 3. Also 2, 4-dinitro phenol did not show any inhibitory effect on the enzyme activity. 4. Acid protease from Penicillium sp. showed a strong milk clotting activity in the presence of Ca ion. 5. This enzyme had a strong proteolytic activity on various substrate, such as casein, denatured hemoglobin, ovalbumin, denatured bovine muscle protein, denatured percine muscle protein and denatured chicken muscle protein.

• BMB Reports
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• v.36 no.2
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• pp.149-153
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• 2003

The dibucaine number (DN) was determined for serum cholinesterase (EC 3.1.1.8, SChE) in plasma samples. The ones with a DN of 79-82 were used, because they had the "usual" SChE variant. The enzyme was assayed colorimetrically by the reaction of 5,5'-dithiobis-[2-nitrobenzoic acid] (DTNB) with the free sulfhydryl groups of thiocholine that were produced by the enzyme reaction with butrylthiocholine (BuTch) or acetylthiocholine (AcTch) substrates, and measured at 412 nm. Dibucaine, a quaternary ammonium compound, inhibited SChE to a minimum within 2 min in a reversible manner. The inhibition was very potent. It had an $IC_{50}$ of $5.3\;{\mu}M$ with BuTch or $3.8\;{\mu}M$ with AcTch. The inhibition was competitive with respect to BuTch with a $K_i$ of $1.3\;{\mu}M$ and a linear-mixed type (competitive/noncompetitive) with respect to AcTch with inhibition constants, $K_i$ and $K_I$ of 0.66 and $2.5\;{\mu}M$, respectively. Dibucaine possesses a butoxy side chain that is similar to the butryl group of BuTch and longer by an ethylene group from AcTch. This may account for the difference in inhibition behavior. It may also suggest the existence of an additional binding site, other than the anionic binding site, and of a hydrophobic nature.

• BMB Reports
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• v.29 no.4
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• pp.365-371
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• 1996

Partially reduced interferon-a ($IFN-{\alpha}$) was cross-linked with thymosin ${\alpha}1$ ($T{\alpha}1$) using sulfo-succinimidyl (4-iodoacetyl) amino benzoate (SIAB), a bifunctional cross-linking reagent. The partially reduced $IFN-{\alpha}$ optimal for the cross-linking reaction was obtained by incubating native $IFN-{\alpha}$ with 0.5 mM DTT at $30^{\circ}C$ for 60~100 min. $T{\alpha}1$ was activated by incubating with sulfo-SIAB at $37^{\circ}C$ for 30 min to produce $T{\alpha}1-IAB$. The $T{\alpha}1-IFN-{\alpha}$ cross-linking was achieved by the reaction of the partially reduced $IFN-{\alpha}$ with $T{\alpha}1-IAB$. This cross-linking was between the sulfhydryl group of Cys1 in $IFN-{\alpha}$ and the N-terminal amino group of $T{\alpha}1$ through acetyl amino benzoate as a spacer. The immunological activity of the cross-linked molecule showed the same extent as that of $T{\alpha}1$, and most of the antiviral activity was retained compared to that of the partially reduced $IFN-{\alpha}$.

• Food Science and Biotechnology
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• v.18 no.1
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• pp.234-238
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• 2009

Effects of ginseng on in vivo antioxidant capacities with age were studied in rats. All rats were reared in the conventional system. Ginseng-treated rats were supplied with ginseng water extracts (25 mg/kg/day) continuously from 6 weeks of age to spontaneous death. None of the rats showed any discernible adverse effects of treatment with ginseng-containing water. There was no significant difference in body weight (BW) gains with age between treated and control groups. However, ginseng extracts did cause a decrease in the level of serum low density lipoprotein (LDL)-cholesterol, glucose, and thiobarbituric acid reactive substances (TBARS) in the treated rats. The activities of superoxide dismutase (SOD), catalase, and glutathione peroxidase in liver cytosol decreased with age in the control group. However, these enzyme activities were well maintained in the ginseng-treated rats and, especially, catalase and glutathione peroxidase activities were consistently higher than in control rats. The levels of total sulfhydryl group (T-SH) and glutathione reductase (GR) were unchanged, and glutathione-s-transferase (GST) activity gradually decreased with age in both groups. There were no differences in T-SH, GR, or GST between the control and treatment groups. These results indicate that long-term administration of ginseng retards age-related deterioration in some biochemical parameters such as cholesterol, glucose, and lactate dehydrogenase in serum and it has an enhancing effect on antioxidant capacity in the liver.

• Journal of Microbiology and Biotechnology
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• v.23 no.3
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• pp.329-334
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• 2013

Uridinediphospho-N-acetylglucosamine enolpyruvyl transferase (MurA, E.C. 2.5.1.7) is an essential bacterial enzyme that catalyzes the first step of the cell wall biosynthetic pathway, which involves the transfer of an enolpyruvyl group from phosphoenolpyruvate to uridinediphospho-Nacetylglucosamine. In this study, novel inhibitors of Haemophilus influenzae MurA (Hi MurA) were identified using high-throughput screening of a chemical library from the Korea Chemical Bank. The identified compounds contain a quinoline moiety and have much lower effective inhibitory concentrations ($IC_{50}$) than fosfomycin, a wellknown inhibitor of MurA. These inhibitors appear to covalently modify the sulfhydryl group of the active site cysteine (C117), since the C117D mutant Hi MurA was not inhibited by these compounds and excess dithiothreitol abolished their inhibitory activities. The increased mass value of Hi MurA after treatment with the identified inhibitor further confirmed that the active-site cysteine residue of Hi MurA is covalently modified by the inhibitor.

• Journal of Acupuncture Research
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• v.22 no.2
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• pp.133-139
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• 2005

Cobrotoxin, a venom of Vipera lebetina turanica, is a group of basic peptidescomposed of 233 amino acids with six disulfide bonds formed by twelve cysteins. NF-kB is activated by subsequent release of inhibitory IkB and translocation of p50. Since sulfhydryl group is present in kinase domain of p50 subunit of NF-kB, cobrotoxin could modify NF-kB activity by protein-protein interaction. We therefore examined effect of cobrotoxin on NF-kB activities in lipopolysaccharide (LPS) and sodium nitroprusside (SNP)-stimulated Raw 264.7 mouse macrophages. Cobrotoxin suppressed the LPS and SNP-induced release of IkB and p50 translocation resulted in inhibition of DNA binding activity of NF-kB. Inhibition of NF-kB resulted in reduction of the LPS and SNP-induced production of inflammatory mediators NO and PGE2 generation. The inhibitory effect of cobrotoxin on the NF-kB activity were blocked by addition of reducing agents dithiothreitol and glutathione. These results demonstrate that cobrotoxin inhibits activation of NF-kB, and suggest that pico to nanomolar range of cobrotoxin could inhibit the expression of genes in the NF-kB signal pathway.