• Journal of Life Science
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• v.16 no.1
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• pp.37-43
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• 2006

Gap junction is an ion channel forming between adjacent cells. It also acts as a membrane channel like sodium or potassium channels in a single cell. The amino acid residues up to the $10^{th}$ position in the amino (N)-terminus of gap junction hemichannel affect gating polarity as well as current-voltage (I-V) relation. While wild-type Cx32 channel shows negative gating polarity and inwardly rectifying I-V relation, T8D channel in which threonine residue at $8^{th}$ position is replaced with negatively charged aspartate residue shows reverse gating polarity and linear I-V relation. It is still unclear whether these changes are resulted from the charge effect or the conformational change of the N-terminus. To clarify this issue, we made a mutant channel harboring cysteine residue at the $8^{th}$ position (T8C) and characterized its biophysical properties using substituted-cysteine accessibility method (SCAM). T8C channel shows negative gating polarity and inwardly rectifying I-V relation as wild-type channel does. This result indicates that the substitution of cysteine residue dose not perturb the original conformation of wild-type channel. To elucidate the charge effect two types of methaenthiosulfonate (MTS) reagents (negatively charged $MTSES^-$ and positively charged $MTSET^+$) were used. When $MTSES^-$ was applied, T8C channel behaved as T8D channel, showing positive gating polarity and linear I-V relation. This result indicates that the addition of a negative charge changes the biophysical properties of T8C channel. However, positively charged $MTSET^+$ maintained the main features of T8C channel as expected. It is likely that the addition of a charge by small MTS reagents does not distort the conformation of the N-terminus. Therefore, the opposite effects of $MTSES^-$ and $MTSETT^+$ on T8C channel suggest that the addition of a charge itself rather than the conformational change of the N-terminus changes gating polarity and I-V relation. Furthermore, the accessibility of MTS reagents to amino acid residues at the $8^{th}$ position supports the idea that the N-terminus of gap junction channel forms or lies in the aqueous pore.

• Journal of the Korean Society of Clothing and Textiles
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• v.34 no.4
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• pp.697-702
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• 2010

This study researches the mechanical and dyeing properties of wool fabric treated with papain. In this study, shrinkage, water contact angle, alkali solubility, and the dyeability of wool fabric treated with papain at the optimal activity condition were measured to confirm the effect of papain treatment. The shrinkage and water contact angle of wool fabric treated with papain decreased more than the untreated wool; however, the alkali solubility and the dyeability increased. L-cysteine was more active than EDTA as an activator of papain.

• Journal of Microbiology and Biotechnology
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• v.25 no.6
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• pp.788-794
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• 2015

Cationic liposomes have been actively used as gene delivery vehicles despite their unsatisfactory efficiencies because of their relatively low toxicity. In this study, we designed novel heterodimeric peptides as nonviral gene delivery systems from TAT and NLS peptides using cysteine-to-cysteine disulfide bonds between the two. Mixing these heterodimeric peptides with DNA before mixing with lipofectamine resulted in higher transfection efficiencies in MCF-7 breast cancer cells than mixing unmodified TAT, NLS, and a simple mixture of TAT and NLS with DNA, but did not show an adverse effect on cell viability. In gel retardation assays, the DNA binding affinities of heterodimeric peptides were stronger than NLS but weaker than TAT. However, this enhancement was only observed when heterodimeric peptides were premixed with DNA before being mixed with lipofectamine. The described novel transfection-enhancing peptide system produced by the heterodimerization of TAT and NLS peptides followed by simple mixing with DNA, increased the gene transfer efficiency of cationic lipids without enhancing cytotoxicity.

• YAKHAK HOEJI
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• v.21 no.4
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• pp.184-192
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• 1977

In the presence of dithionite, two kinds of molybdothiol complexes, particularly isolated Mo-cysteine complexes, used as models for xanthine oxidase or aldehyde oxidase exhibited catalytic activity on the reduction of nitrofurazone to its amino derivative. Of the two Mo-cysteine complexes, the activity of oxo-bridged one was apparently greater than that of sulfido-bridged one. The promoting effect was hardly shown by added cofactors or their replacements of the enzymes. The catalyzed reduction is considered to take place by consecutive direct two-electron transfer mechanism from catalytically active reduced form of the molybdothiol complexes to nitrofurazone and the probable intermediates.

• 한국생물공학회:학술대회논문집
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• 2002.04a
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• pp.205-207
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• 2002

Experiments were carried out to the effect of various amino acids on the production of tetraacetylphytosphingosine (TAPS). Among various amino acids were tested, cysteine decreased the production of TAPS at 7 days of flask culture. Especially, Serine is precursor of TAPS but didn't affect the production of TAPS. Glycine and glutamate increased the production of TAPS. Especially, glutamate increased 20% of cell mass and 37% of TAPS production.

• Animal cells and systems
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• v.2 no.2
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• pp.243-248
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• 1998

We have partially sequenced glutaminyl cyclases from several mammalian and one avian species and found that the two cysteine residues of the human glutaminyl cyclase are completely conserved. The mammalian glutaminyl cyclase has been reported to possess reactive thiols (Busby, Jr, et aI., 1987, J BioI Chern 262, 8532-8536). Mutagenesis of these cysteine residues, however, resulted in only a slight decrease in enzyme activity. Likewise, the recombinant human enzyme was completely resistant to attempted chemical modification of the putative reactive thiols. Although the human glutaminyl cyclase did not appear to have reactive thiols, it was sensitive to diethylpyrocarbonate and acetylimidazole, indicating the presence of functionally important histidine and tyrosine residues which could act as acid/base catalysts. Almost identical deuterium solvent isotope effect (1.2 vs 1.3) upon the reaction by the human and papaya enzymes, respectively, provides an evidence both animal and plant glutaminyl cyclases catalyze pyroglutamyl-peptide formation by intramolecular cyclization.

• Archives of Pharmacal Research
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• v.21 no.6
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• pp.790-792
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• 1998

• Journal of Photoscience
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• v.9 no.2
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• pp.201-204
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• 2002

Epidermal cells produce a panel of antioxidants as well as cytokines after UVB irradiation, which counteract reactive oxygen species, however, how these antioxidants might regulate melanogenesis is unclear. An important constituent of the cellular antioxidant buffering system which controls the redox state of proteins is thioredoxin (TRX), a 13-kD protein that catalyzes thiol-disulfide exchange reactions, regulates activation of transcription factors, and possesses several other biological functions similar to cytokines. TRX suppressed the UVB-induced production and secretion of $\alpha$-melanocyte stimulating hormone ($\alpha$-MSH) and of adrenocorticotropic hormone (ACTH), and also suppressed proopiomelanocortin (POMC) mRNA expression by normal human keratinocyte (KC)s. Further, L-cysteine, N-acetyl-cysteine, $\alpha$-tocopheryl ferulate showed suppressive effect on UVB-induced POMC mRNA expression. However, TRX released from UVB-irradiated KCs stimulated melanogenesis by up-regulating MSH receptor expression and its binding activity in melanocyte (MC)s. UVB-induced KC derived cytokines such as IL1, IL6, and ET1 upregulated MSH-receptor binding ability as well as MCl-R mRNA expression in cultured normal human MCs. MCl-R has a tendency to be upregulated by UVB-induced KC-derived cytokines as well as by direct UVB irradiation. These results suggest that antioxidants such as TRX suppresses UVB induction of POMC, but in the case of MCl-R, this gene can be mainly in the trend of upregulation by UVB-induced KC-derived factors including TRX.

• The Korean Journal of Food And Nutrition
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• v.25 no.4
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• pp.863-870
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• 2012

Though hydrogen peroxide ($H_2O_2$) causes a deleterious effect to cells with its reactive oxygen species resulting in cell death, S-allyl cysteine (SAC, a bioactive organosulfur compound of aged garlic extract) has been known to have a cytoprotective effect. Few reported profiles of gene expression of $H_2O_2$ and SAC treated human cord blood derived mesenchymal stem cells (MSC). This study revealed changes in the profile of twenty-one genes grouped by oxidative stress, antioxidant, cell death, anti-apoptosis and anti-aging by quantitative real time PCR. A concentration of $100{\mu}M$ of SAC or $50{\mu}M$ of $H_2O_2$ was applied to MSC which show moderate growth and apoptosis pattern. $H_2O_2$ treatment enhanced expression of eleven genes out of twenty-one genes compared with that of control group, on the contrary SAC suppressed expression of eighteen genes out of twenty-one genes except C ros oncogene. SAC decreased expression of oxidative stress genes such as SOD1, CAT and GPX. These results seemed consistent with reports which elucidated over-expression of NF-${\kappa}$B by $H_2O_2$, and suppression of it by SAC. This study will confer basic information for further experiments regarding the effects of SAC on gene levels.

• Clinical and Experimental Reproductive Medicine
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• v.48 no.4
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• pp.316-321
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• 2021

Objective: Amino acids can protect sperm structure in cryopreservation due to their antioxidant properties. Therefore, the present study aimed to investigate the protective effect of L-carnitine (LC) and N-acetyl cysteine (NAC) on motility parameters, plasma membrane integrity (PMI), mitochondrial membrane potential (MMP), DNA damage, and human sperm intracellular reactive oxygen species (ROS) during vitrification. Methods: Twenty normal human sperm samples were examined. Each sample was divided into six equal groups: LC (1 and 10 mM), NAC (5 and 10 mM), and cryopreserved and fresh control groups. Results: The groups treated with LC and NAC showed favorable findings in terms of motility parameters, DNA damage, and MMP. Significantly higher levels of intracellular ROS were observed in all cryopreserved groups than in the fresh group (p≤0.05). The presence of LC and NAC at both concentrations caused an increase in PMI, MMP, and progressive motility parameters, as well as a significant reduction in intracellular ROS compared to the control group (p≤0.05). The concentrations of the amino acids did not show any significant effect. Conclusion: LC and NAC are promising as potential additives in sperm cryopreservation.