scholarly journals Evaluation of p-phenylene-bis and phenyl dithiocarbamate sodium salts as inhibitors of mushroom tyrosinase.

2010 ◽  
Vol 57 (3) ◽  
Author(s):  
Ehsan Amin ◽  
Ali Akbar Saboury ◽  
Hassan Mansouri-Torshizi ◽  
Samane Zolghadri ◽  
Abdol-Khalegh Bordbar
Keyword(s):  
Sodium Salt ◽  
Tertiary Structure ◽  
Hydrophobic Interactions ◽  
Copper Ions ◽  
Water Soluble ◽  
Spectroscopic Techniques ◽  
Mushroom Tyrosinase ◽  
Enzyme Active Site ◽  
Fluorescence Studies ◽  
Head Groups

Two structurally related compounds, phenyl dithiocarbamate sodium salt (I) and p-phenylene-bis (dithiocarbamate) sodium salt (II) were prepared by reaction of the parent aniline and p-phenylenediamine with CS₂ in the presence of sodium hydroxide. These water soluble compounds were characterized by spectroscopic techniques, IR, ¹H NMR and elemental analysis. The inhibitory effects of both compounds on both activities of mushroom tyrosinase (MT) from Agricus bisporus were studied at two temperatures, 27°C and 37°C. L-3, 4-dihydroxyphenylalanine (L-DOPA), and l-tyrosine were used as natural substrates for the catecholase and cresolase enzyme reactions, respectively. Kinetic analysis confirmed noncompetitive inhibition mode of I and mixed type of II on both activities of MT; I and II inhibit MT with inhibition constants (K(I)) of 300 µM and 4 µM, respectively. Analysis of thermodynamic parameters indicated predominant involvement of hydrophobic interactions in binding of I and electrostatic ones in binding of II to MT. It seems that II is a more potent MT inhibitor due to its two charged head groups able to chelate copper ions in the enzyme active site. Intrinsic fluorescence studies as a function of concentrations of both compounds showed unexpectedly quenching of emission intensity without any shift of emission maximum. Extrinsic ANS-fluorescence indicated that only binding of I induces limited changes in the tertiary structure of MT, in agreement with the postulated hydrophobic nature of the binding mechanism.

Thermal Investigation of P-Phenylene-Bis and Phenyl Dithiocarbamate Binding to Mushroom Tyrosinase

2011 ◽  
Vol 110-116 ◽  
pp. 1970-1974
Author(s):  
Gholamreza Rezaei Behbehani ◽  
M. Mehreshtiagh
Keyword(s):  
Active Site ◽  
Phosphate Buffer ◽  
Electrostatic Interactions ◽  
Structural Changes ◽  
Copper Ions ◽  
Mushroom Tyrosinase ◽  
Binding Properties ◽  
Enzyme Active Site ◽  
Head Groups ◽  
Tyrosinase Enzyme

The binding properties and structural changes of mushroom tyrosinase enzyme, MT, due to its interaction with phenyl dithiocarbamate (I) and p-phenylene-bis dithiocarbamate (II) were investigated at 27 and 37°C in phosphate buffer (10 mmol.L-1) at pH=6.8 by isothermal titration calorimetric (ITC). Thermodynamic analysis indicated that predominant mode of interaction was hydrophobic in binding of I to MT, meanwhile the binding of II to MT essentially depends on electrostatic interactions. It seems thatII is a more potent MT inhibitor due to its two charged head groups able to chelate copper ions in the enzyme active site. It was concluded that MT has two distinct sites for p-phenylene-bis and phenyl dithiocarbamate.

Water-soluble polymeric particle embedded cryogels: Synthesis, characterisation and adsorption of haemoglobin

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Kadir Erol ◽  
Melda Bolat Bülter ◽  
Dursun Ali Köse ◽  
Hatice Kaplan Can
Keyword(s):  
Copper Ions ◽  
Langmuir Model ◽  
Water Soluble ◽  
Hydroxyethyl Methacrylate ◽  
Adsorption Ability ◽  
Adsorption Interaction ◽  
Polymeric Particle ◽  
Adsorption Desorption ◽  
Desorption Cycle ◽  
Soluble Poly

Abstract Making cryogels, which are among today’s accepted adsorbents, more functional with different methods, has been one of the subjects spent overtime. In this study, water-soluble poly(maleic anhydride-alt-acrylic acid) polymer embedded in poly(2-hydroxyethyl methacrylate) cryogels. Copper ions were then immobilised to this structure, and this polymer was used for adsorption of haemoglobin from aqueous systems. Adsorption interaction was carried out on an electrostatic basis, and approximately 448.62 mg haemoglobin/g polymer adsorption capacity value was obtained. It was found that the same material has managed to maintain its adsorption ability by 90.3% even after the use of it five times in the adsorption/desorption cycle. The adsorption interaction was determined to be appropriate for the Langmuir model by isotherm studies. The change in Gibbs free energy value was calculated as −2.168 kJ/mol.

scholarly journals Interactions between 4-thiothymidine and water-soluble cyclodextrins: Evidence for supramolecular structures in aqueous solutions

2016 ◽  
Vol 12 ◽  
pp. 549-563 ◽  
Author(s):  
Vito Rizzi ◽  
Sergio Matera ◽  
Paola Semeraro ◽  
Paola Fini ◽  
Pinalysa Cosma
Keyword(s):  
Inclusion Complexes ◽  
Pyrimidine Ring ◽  
Protective Role ◽  
Supramolecular Structures ◽  
Water Soluble ◽  
Aqueous Environment ◽  
Spectroscopic Techniques ◽  
Guest Molecules ◽  
H Nmr ◽  
Cv Measurements

Since several years the inclusion of organic compounds (guests) within the hydrophobic cavity (host) of cyclodextrins (CDs) has been the subject of many investigations. Interestingly, the formation of inclusion complexes could affect the properties of the guest molecules and, for example, the influence of the delivery system can be a method to improve/change the photochemical behavior of the guest. In particular, very recent studies have shown the protective role of CDs preventing the degradation of the encapsulated guest. Starting from this consideration, in this work, only the structure and complexation mode of the inclusion complexes involving 4-thiothymidine (S4TdR, a known photosensitizer) and five CDs, namely 2-hydroxypropyl-α-cyclodextrin (2-HP-α-CD), 2-hydroxypropyl-β-cyclodextrin (2-HP-β-CD), 2-hydroxypropyl-γ-cyclodextrin (2-HP-γ-CD), heptakis-(2,6-di-O-methyl)-β-cyclodextrin (DIMEB CD) and heptakis-(2,3,6-tri-O-methyl)-β-cyclodextrin (TRIMEB CD) were investigated by different spectroscopic techniques (UV–vis, FTIR–ATR, 1H NMR) and cyclic voltammetry analysis (CV). This work is necessary for a prospective research on the photoreactivity of S4TdR in aqueous environment and in the presence of CDs to prevent its degradation under irradiation. UV–vis, FTIR–ATR and CV measurements suggested the formation of supramolecular structures involving the employed CDs and mainly the pyrimidine ring of S4TdR. 1H NMR analyses confirmed such indication, unveiling the presence of inclusion complexes. The strongest and deepest interactions were suggested when TRIMEB and DIMEB CDs were studied. The S4TdR affinity towards CDs was also evaluated by using the Benesi–Hildebrand (B–H) equation at 25 °C employing CV and 1H NMR methods. The stoichiometry of the interaction was also inferred and it appears to be 1:1 for all examined CDs.

scholarly journals Solvolysis of the Tumor-Inhibiting Ru(III)-Complex trans-Tetrachlorobis(Indazole)Ruthenate(III)

2000 ◽  
Vol 7 (4) ◽  
pp. 225-232 ◽  
Author(s):  
Thomas Pieper ◽  
Wolfgang Peti ◽  
Bernhard K. Keppler
Keyword(s):  
Sodium Salt ◽  
Buffer System ◽  
Spectroscopic Techniques ◽  
Tumor Models ◽  
Solubility In Water ◽  
Aqueous Acetonitrile ◽  
Hydrolysis Of

The ruthenium(III) complex Hlnd trans-[RuCl4,(ind)2], with two trans-standing indazole (ind) ligands bound to ruthenium via nitrogen, shows remarkable activity in different tumor models in vitro and in vivo. The solvolysis of the complex trans-[RuCl4,(ind)2]- has been investigated by means of spectroscopic techniques (UV/vis, NMR)in different solvents. We investigated the indazolium as well as the sodium salt, the latter showing improved solubility in water. In aqueous acetonitrile and ethanol the solvolysis results in one main solvento complex. The hydrolysis of the complex is more complicated and depends on the pH of the solution as well as on the buffer system.

scholarly journals Investigation of the Effect of Sodium Selenate on Acetylcholinesterase Activity under Extremely Low Frequency Electromagnetic Field

2012 ◽  
Vol 4 (1) ◽  
Author(s):  
Ezzatollah Fathi ◽  
Raheleh Farahzadi
Keyword(s):  
Electromagnetic Field ◽  
Structural Changes ◽  
Tertiary Structure ◽  
Low Frequency ◽  
Acetylcholinesterase Activity ◽  
The Elderly ◽  
Skin Aging ◽  
Sodium Selenate ◽  
Spectroscopic Techniques ◽  
Extremely Low Frequency

Acetylcholinestrase (AChE EC 3.1.1.7) is one of the most important enzymes in nervous system, which plays a role in Alzheimer’s disease. Selenium is a vital micronutrient and many investigations have been performed about the physiological, biochemical and behavioral effects of this element, such as postponing the Alzheimer's symptoms in the elderly and delaying the initiation signs of skin aging. Recent studies have shown that this element protects various enzymes against the toxicity caused by heavy metals such as; Pb, Al, Cu and Cd. AChE activity is altered under the influence of extremely low frequency electromagnetic field (ELF-EMF). In this study, the effects of ELF-EMF, with 0.3 mT field intensity and 50, 100, 217 Hz frequencies, were investigated on the AChE, in the presence of different concentrations of sodium selenate, using UV-Visible, fluorescence and circular dichroism spectroscopic techniques. The results demonstrated that the enzyme activity declined by increasing the frequency and the amount of sodium selenate. Also, significant structural changes occurred in the secondary and tertiary structures of AChE. Our results showed that with increasing the concentration of sodium selenate transition from α-helix to β-structure was appeared in the presence of ELF-EMF. In conclusion, according to changes observed in the secondary and tertiary structure of enzyme, it is proposed that these fields are able to affect the structure and dynamics of the active site gorge of AChE.

scholarly journals Synthesis of Water-Soluble 7-O-Carboxymethyl-Genistein

2017 ◽  
Vol 41 (3) ◽  
pp. 183-185
Author(s):  
Zhiling Cao ◽  
Qiao Wu ◽  
Jing Cheng ◽  
Dandan Zhu ◽  
Wengqi Teng ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Sodium Salt ◽  
Water Solubility ◽  
Clinical Chemistry ◽  
Water Soluble ◽  
Aqueous Acetic Acid ◽  
Carboxylate Group ◽  
Target Compound ◽  
Catalysed Reaction

A three-step synthesis from genistein of the water-soluble sodium salt of 7-O-carboxymethyl-genistein is described. Base-catalysed reaction of genistein with t-butyl bromoacetate gave 7-O-(carbo-t-butoxy)methyl-genistein, which was hydrolysed by aqueous acetic acid to 7-O-carboxymethyl-genistein and neutralised (NaHCO3) to give the target compound. The carboxylate group enhanced the water-solubility of genistein more than a thousand-fold and the new derivate will be useful as a candidate compound in pharmacological and clinical chemistry studies of isoflavones.

Effect of Glutathione Depletion on Haemoglobin and Membrane Integrity of Red Blood Cells of Rats

1996 ◽  
Vol 24 (1) ◽  
pp. 40-46 ◽  
Author(s):  
K S Park ◽  
M J Kim ◽  
J S Ho ◽  
C K Ryu ◽  
J H Chung
Keyword(s):  
Red Blood Cells ◽  
Sodium Salt ◽  
Blood Cells ◽  
Membrane Integrity ◽  
Water Soluble ◽  
Glutathione Depletion ◽  
Haemoglobin Content

The effects of streptozocin (streptozotocin) and water-soluble menadione (menadione bisulphite, sodium salt) on the haemoglobin content and membrane integrity of red blood cells were investigated. Both menadione bisulphite and streptozocin significantly depleted glutathione but menadione bisulphite was much more effective in reducing glutathione than was streptozocin. Menadione bisulphite, at concentrations above 0.1 mM, caused substantial conversion of oxygenated haemoglobin into methaemoglobin while streptozocin did not alter the haemoglobin content of the red blood cells at concentrations of up to 100 mM. Both agents demonstrated only a modest ability to haemolyse the red blood cells, even at concentrations up to 300 mM. These results suggest that depletion of glutathione by menadione causes the conversion of oxyhaemoglobin to methaemoglobin. In contrast, streptozocin-induced glutathione depletion does not seem to be well correlated with alterations in haemoglobin content.

Syntheses and properties of acetylene-linked bis- and trisporphyrins toward two-photon photodynamic therapy

2007 ◽  
Vol 11 (06) ◽  
pp. 406-417 ◽  
Author(s):  
Yusuke Inaba ◽  
Kazuya Ogawa ◽  
Yoshiaki Kobuke
Keyword(s):  
Photodynamic Therapy ◽  
Cross Section ◽  
Sodium Salt ◽  
Absorption Cross Section ◽  
Water Soluble ◽  
Photon Absorption ◽  
Absorption Cross ◽  
Two Photon Absorption ◽  
Photon Irradiation ◽  
Two Photon

Acetylene-bridged bisporphyrins and trisporphyrins having branched bulky bis(carboxylethyl)methyl meso-substituents were synthesized. These compounds showed large effective two-photon absorption cross-section values at 890 nm measured by using a nanosecond Z-scan method. Sodium salt of hydrolyzed trisporphyrins showed broad and red-shifted Q-bands over 900 nm. Two-photon absorption cross-section values of water-soluble dimers in water were similar to, or slightly larger than, those of ester forms evaluated in toluene. Furthermore, the generation of singlet oxygen upon one-photon irradiation for dimers in water was confirmed.

Spectral properties of ionic derivatives of pyrene and their aggregates with anionic surfactant and polyelectrolyte

1995 ◽  
Vol 73 (11) ◽  
pp. 1948-1954 ◽  
Author(s):  
Pavol Hrdlovič ◽  
Lubica Horinová ◽  
Štefan Chmela
Keyword(s):  
Butyric Acid ◽  
Sodium Salt ◽  
Polyacrylic Acid ◽  
Sodium Dodecylsulfate ◽  
Green Emission ◽  
Water Soluble ◽  
Diffusion Controlled ◽  
Packed Structure ◽  
Bimolecular Quenching ◽  
Derivatives Of

A multifunctional probe based on pyrene, the chloride of the 2,2,6,6-tetramethyl-4-hydroxy-piperidinium ester of 4-(1-pyrene)butyric acid, at a concentration of 5 × 10−5 mol dm−3 exhibits excimer-like green emission with the maximum at 480 nm in the presence of sodium dodecylsulfate below its critical micelle concentration. A similar effect has been observed for this probe in the presence of the sodium salt of polyacrylic acid in the same concentration range. 1-Pyrenemethylammonium chloride exhibits a broad green excimer-like emission for sodium dodecylsulfate but not for the sodium salt of polyacrylic acid. The quenching constants of the monomeric and excimer-like emissions were determined for acrylamide, 1-oxo-2,2,6,6-tetramethyl-4-hydroxypiperidine, potassium iodide, and copper(II) sulfate, representing neutral, ionic, and free-radical types of quenchers. The rate constants of quenching for N-oxyl radicals indicate that the monomeric emission from both water-soluble probes is diffusion controlled. For other types of quenchers the rate constant of bimolecular quenching is lower. The quenching of the excimer-like emission of an aggregate of the chloride of the 2,2,6,6-tetramethyl-4-hydroxypiperidinium ester of 4-(1-pyrene)butyric acid is less efficient than in the case of 1-pyrenemethylammonium chloride, which indicates a more packed structure of the former aggregate. Keywords: pyrene, ionic derivative, emission, micelle, aggregation, quenching.

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