The present study was performed to evaluate the effect of sulfhydryl compounds, cysteine and glutathione, on the size of melanosomes and the ratio of melanosormai stages of epidermal melanocytes in UV-irradiated black mice. The results were as follows; 1. Both of cysteine and glutathione showed significant diminution in the short axis of melanosomes and the percentage of stage 4 melanosomes of epidermal melanocytes in C57BL black mice skin. 2. The length of short axis of melanosomes in glutathione-treated group is smaller than those in cysteine-treated group at the end of 3rd week of intraperitoneal injection. The percentage of stage IV melanosomes significantly decreased in glutathione-treated group and cysteine-treated group at the end of 3rd week and 5th week respectively. 3. In glutathione-treated group, the short axis of melanosomes and the percentage of stage 4 melanosomes both decreased in proportional to the period of intraperitoneal in]ection.
Animals ; Axis, Cervical Vertebra ; Cysteine ; Glutathione ; Injections, Intraperitoneal ; Melanocytes* ; Melanosomes ; Mice* ; Skin ; Sulfhydryl Compounds*

When reduced glutathione(GSH) was incubated at neutral pH and at 37degrees, its concentration decteased slowly with formation of oxidized glutathione(GSSG). Autooxidation of GSH was accelerated by Cu2+ and Hg2+, but not by other common mono-, di-, and tri-valent cations. Tranthyretin was found to stimulate autooxidation of GSH in the presence or absence of Cu2+ and Hg2+. EDTA inhibited perfectly the autooxidation of GSH regardless of the presence of transthyretin. The stimulating activity of transthyretin was maximal at pH 7.0, declining progressively with increase or decrease of pH from 7.0. Sulfhydryl-blocking agents such as p-hydroxymercuribenzoic acid and N-ethylmaleimide markedly inhibited the stimulating activity of transthyretin. Transthyretin stimulated autooxidation of other sulfhydryl compounds such as dithiothreitol and cysteine. However, it did not show a significant effect on autooxidation of sulfhydryl group of egg albumin and eye lens proteins. And transthyretin did not cause any oxidative change to thyroxine(T4), 3, 5, 3'-tri iodo thyronine(T3) and 3, 3', 5'-triiodothyronine(rT3) bound to it in the presence of GSH and Cu2+. The above results suggest that transthyretin may play a role in regulation of oxidized status of sulfhydryl groups in blood plasma and cerebrospinal fluid.
Cations ; Cerebrospinal Fluid ; Crystallins ; Cysteine ; Dithiothreitol ; Edetic Acid ; Ethylmaleimide ; Glutathione* ; Hydrogen-Ion Concentration ; Ovum ; Plasma ; Prealbumin* ; Sulfhydryl Compounds

Redox signal transduction, especially the oxidative modification of proein thiols, correlates with many diseases and becomes an expanding research area. However, there was rare method for quick and specific detection of protein thiols and their oxidative modification in living cells. In this article, we review the current chemical strategies for the detection and quantification of protein thiols and related cysteine oxidation. We also look into the future of the development of fluorescent probes for protein thiols and their potential application in the research of reactive cysteine proteomes and early detection of redox-related diseases.
Animals ; Cysteine ; metabolism ; Fluorescent Dyes ; Humans ; Nitrosation ; Oxidation-Reduction ; Proteins ; chemistry ; metabolism ; Reactive Nitrogen Species ; metabolism ; Reactive Oxygen Species ; metabolism ; Sulfenic Acids ; analysis ; Sulfhydryl Compounds ; analysis ; chemistry ; metabolism

Antirheumatic gold compounds have been shown to inhibit NF-kB activation by blocking IkB kinase (IKK) activity. To examine the possible inhibitory mechanism of gold compounds, we expressed wild type and mutant forms of IKk alpha and beta subunits in COS-7 cells and determined the effect of gold on the activity of these enzymes both in vivo and in vitro. Substitution of Cys-179 of IKK beta with alanine (C179A) rendered the enzyme to become resistant to inhibition by a gold compound auranofin, however, similar protective effect was not observed with an equivalent level of IKK alpha (C178A) mutant expressed in the cells. Auranofin inhibited constitutively active IKK alpha and beta and variants; IKK alpha (S176E, S180E) or IKK beta (S177E, S181E), suggesting that gold directly cause inhibition of activated enzyme. The different inhibitory effect of auranofin on IKK alpha (C178A) and IKK beta (C179A) mutants indicates that gold could inhibit the two subunits of IKK in a different mode, and the inhibition of NF- kB and IKK activation induced by inflammatory signals in gold-treated cells appears through its interaction with Cys-179 of IKK beta.
Amino Acid Substitution ; Animals ; Auranofin/*pharmacology ; COS Cells ; Cysteine/genetics/*metabolism ; Enzyme Activation/drug effects ; Gold Compounds/*pharmacology ; Protein Subunits/chemistry ; Protein-Serine-Threonine Kinases/*antagonists & inhibitors/chemistry/genetics/*metabolism ; Sulfhydryl Compounds/pharmacology

OBJECTIVES: To evaluate the protective effects of glutathione (GSH) on the cytotoxicity of mercurial compounds(CH3HgCl, HgCl2) or cadmium chloride(CdCl2) in EMT-6 cells. METHODS: The compounds investigated were CH3HgCl, HgCl2, CdCl2, GSH, buthionine sulfoximine(BSO), L-2-oxothiazolidine-4-carboxylic acid(OTC). Cytotoxicity analysis consist of nitric oxide(NO) production, ATP production and cell viability. RESULTS: Mercurial compounds and cadmium chloride significantly decreased cell viability and the synthesis of NO and cellular ATP in EMT-6 cells. GSH was not toxic at concentrations of 0 - 1.6 mM. In the presence of GSH, mercurial compounds and cadmium did not decrease the production of ATP and nitrite in EMT-6 cells. The protective effects of GSH against the cytotoxicity of mercurial compounds and cadmium depended on the concentration of added GSH to the culture medium for EMT-6 cells. We evaluated the effects of intracellular GSH level on mercury- or cadmium-induced cytotoxicity by the pretreatment experiments. Pretreatment of GSH was not changed NO2- and ATP production, and pretreatment of BSO was decreased in dose- and time-dependent manner. Pretreatment of OTC was increased NO2- and ATP production in dose- and time-dependent manner. Because intracellular GSH level was increased by OTC pretreatment, the protective effect on mercury- and cadmium-induced cytotoxicity was increased. CONCLUSIONS: These results indicated that sulfhydryl compounds had the protective effects against mercury-induced cytotoxicity by the intracellular GSH levels.
Adenosine Triphosphate ; Cadmium Chloride ; Cadmium* ; Cell Survival ; Glutathione* ; Mercuric Chloride ; Nitric Oxide ; Sulfhydryl Compounds

This present study is to detect the content of free thiols(-SH) in the horn derived traditional Chinese medicines( TCMs) from different animals and different regions by using fluorescence derivatization method. TCEP was used as a disulfide bond reducing agent,while SBD-F as a derivatization reagent. Fluorescent spectrophotometry was used to determine the content of-SH,and the maximum excitation wavelength and emission wavelength were set as 375 and 510 nm,respectively. As a result,under the optimized condition,the extraction of Caprae Hircus Cornu showed the highest free-SH concentration,followed by Bovis Grunniens Cornu,Bubali Cornu,and Elaphuri Davidiani Cornu. In the present study,we point out that the-SH-contained components might be the most important material basis in animal horn derived TCMs. With good accurate,sensitive and rapid properties,the present method can provide reference basis for the quality evaluation of animal horn derived TCMs and guides for the investigation on effective material basis.
Animals ; Cornus ; Drugs, Chinese Herbal ; Horns ; Medicine, Chinese Traditional ; Sulfhydryl Compounds

OBJECTIVES: To design and prepare silk fibroin/hyaluronic acid composite hydrogel. METHODS: The thiol modified silk fibroin and the double-bond modified hyaluronic acid were rapidly cured into gels through thiol-ene click polymerization under ultraviolet light condition. The grafting rate of modified silk fibroin and hyaluronic acid was characterized by ¹H NMR spectroscopy; the gel point and the internal microstructure of hydrogels were characterized by rheological test and scanning electron microscopy; the mechanical properties were characterized by compression test; the swelling rate and degradation rate were determined by mass method. The hydrogel was co-cultured with the cells, the cytotoxicity was measured by the lactate dehydrogenase method, the cell adhesion was measured by the float count method, and the cell growth and differentiation on the surface of the gel were observed by scanning electron microscope and fluorescence microscope. RESULTS: The functional group substitution degrees of modified silk fibroin and hyaluronic acid were 17.99% and 48.03%, respectively. The prepared silk fibroin/hyaluronic acid composite hydrogel had a gel point of 40-60 s and had a porous structure inside the gel. The compressive strength was as high as 450 kPa and it would not break after ten cycles. The water absorption capacity of the composite hydrogel was 4-10 times of its own weight. Degradation experiments showed that the hydrogel was biodegradable, and the degradation rate reached 28%-42% after 35 d. The cell biology experiments showed that the cytotoxicity of the composite gel was low, the cell adhesion was good, and the growth and differentiation of the cells on the surface of the gel were good. CONCLUSIONS The photocurable silk fibroin/hyaluronic acid composite hydrogel can form a gel quickly, and has excellent mechanical properties, adjustable swelling rate and degradation degree, good biocompatibility, so it has promising application prospects in biomedicine.
Fibroins/chemistry* ; Hydrogels/chemistry* ; Hyaluronic Acid/chemistry* ; Biocompatible Materials/chemistry* ; Click Chemistry ; Sulfhydryl Compounds ; Silk/chemistry*

The aimed of this study was to prepare stabilized thiomers to overcome the poor stability character of traditional thiomers. Poly(acrylic acid)-cysteine (PAA-Cys) was synthesized by conjugating cysteine with poly(acrylic acid) and poly(acrylic acid)-cysteine-6-mercaptonicotinic acid (PAA-Cys-6MNA, stabilized thiomers) was synthesized by grafting a protecting group 6-mercaptonicotinic acid (6MNA) with PAA-Cys. The free thiol of PAA-Cys was determined by Ellmann's reagent method and the ratio of 6MNA coupled was determined by glutathione reduction method. The study of permeation enhancement and stabilized function was conducted by using Franz diffusion cell method, with fluorescein isothiocyanate dextran (FD4) used as model drug. The influence of polymers on tight junctions of Caco-2 cell monolayer was detected with laser scanning confocal fluorescence microscope. The results indicated that both PAA-Cys and PAA-Cys-6MNA could promote the permeation of FD4 across excised rat intestine, and the permeation function of PAA-Cys-6MNA was not influence by the pH of the storage environment and the oxidation of air after the protecting group 6MNA was grafted. The distribution of tight junction protein of Caco-2 cell monolayer F-actin was influenced after incubation with PAA-Cys and PAA-Cys-6MNA. In conclusion, stabilized thiomers (PAA-Cys-6MNA) maintained the permeation function compared with the traditional thiomers (PAA-Cys) and its stability was improved. The mechanism of the permeation enhancement function of the polymers might be related to their influence on tight junction relating proteins of cells.
Acrylic Resins ; chemistry ; Actins ; metabolism ; Animals ; Caco-2 Cells ; Cysteine ; chemistry ; Dextrans ; Fluorescein-5-isothiocyanate ; analogs & derivatives ; Glutathione ; Humans ; Intestinal Absorption ; Intestinal Mucosa ; drug effects ; Nicotinic Acids ; chemistry ; Rats ; Sulfhydryl Compounds ; chemistry

The effect of selenium on the tissue sulfhydryl group content and lipid peroxide-destorying enzyme system in the liver, kidney and testis of rat treated with mercury was investigated. The male rats were injected s.c. with HgCl2 (10 micromoles/kg BW) and orally received Na2SeO3 (13 micromoles/kg BW) simultaneously. After 3 days, liver, kidney and testis were removed and analyzed. Mercury decreased the total sulfhydryl group content in the kidney by 25% and the total glutathione content in the kidney and testis by 50% and 36%, respectively, with no changes in other tissues. There was 12% increase in the total sulfhydryl group but not in the total glutathione content in kidney by a simul-taneous treatment of Se and Hg. Glutathione peroxidase (GSH-Px) activities were decreased by 63% in the liver and 69% in the kidney, and glutathione reductase (GSH-Rd) activity was increased in the tests by 16% by the Hg treatment with no changes in Other tissues. Hg had no effect upon glutathione-S-transferase activities in all organs examined. Simultaneous Se treatment increased GSH-Rd activity in the kidney by 23% and GSH-Px activities in liver and kidney by 24% and 21%, respectively, compared to the Hg-treated group. These data indicate that the alleviation of Hg toxicity by Se treatment is well correlated with the protein sulfhydryl group content and GSH-Px activity.
Animal ; Glutathione/metabolism* ; Glutathione Peroxidase/analysis ; Glutathione Reductase/analysis ; Male ; Mercury/toxicity* ; Rats ; Selenium/pharmacology* ; Sulfhydryl Compounds/analysis*

This study was conducted to investigate the occurrence of oxidative stress in the heart tissue of rats infected with Trypanosoma evansi. Rats were divided into 2 groups (A and B) with 12 animals each, and further subdivided into 4 subgroups (A1 and A2, 6 animals/each; and B1 and B2, 6 animals/each). Animals in the groups B1 and B2 were subcutaneously inoculated with T. evansi. Thiobarbituric acid reactive substances (TBARS), superoxide dismutase activity (SOD), glutathione S-transferase activity (GST), reduced glutathione activity (GSH), and non-protein thiols (NPSH) in the heart tissue were evaluated. At day 5 and 15 post-infection (PI), an increase in the TBARS levels and a decrease in the SOD activity (P<0.05) were observed. GSH and GST activities were decreased in infected animals at day 15 PI (P<0.05). Considering the proper functioning of the heart, it is possible that the changes in the activity of these enzymes involved in the oxidative stress may be related, at least in part, in the pathophysiology of rats infected with T. evansi.
Animals ; Glutathione ; Glutathione Transferase ; Heart* ; Oxidative Stress* ; Rats* ; Sulfhydryl Compounds ; Superoxide Dismutase ; Thiobarbituric Acid Reactive Substances ; Trypanosoma*