Na+/K+-atpase - activity and inhibition

The aim of the study was to give an overview of the mechanism of inhibition of Na+/K+-ATPase activity. For this purpose, the effect of ouabain like compounds (digoxin, gitoxin), platinum group complexes ([PdCl4]2-, [PdCl(dien)]+ and [PdCl(Me4dien)]+), transition metal ions (Cu2+, Zn2+, Fe2+, Co2+) and heavy metal ions (Hg2+, Pb2+, Cd2+) on the activity of Na+/K+-ATPase isolated from rat synaptic plasma membranes (SPM), cortex of pig and human erythrocytes and was investigated.Physical chemistry 2008 : 9th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 24-28 September 200

Inhibition of myeloperoxidase by quercetin

Reaction mechanism of quercetin induced inhibition of myeloperoxidase isolated from human neutrophils was proposed by following peroxidase activity of the enzyme, using the o-dianisidine and H2O2 as substrates. The dependence of initial reaction rate vs. H2O2 concentration in the absence and presence of quercetin revealed the reaction mechanism that involved the enzyme inhibition by the excess of the substrate. The rate and equililbria constants for proposed reaction paths were determinedPhysical chemistry 2006 : 8th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 26-29 September 200

Interaction of gold nanoparticles with rat brain synaptosomal plasma membrane Na+/K+-ATPase and Mg2+-ATPase

The aim of the work was to investigate the interaction between borate capped gold nanoparticles (AuNPs) and the rat brain synaptosomal plasma membranes (SPM), as well as the effects of these AuNPs on SPM Na+ /K+ - ATPase and Mg2+-ATPase activity. Influence of AuNPs on Na+ /K+ -ATPase and Mg2+-ATPase activity was investigated as the function of AuNPs and protein concentration and preincubation time. AuNPs induced the stimulation of Na+ /K+ -ATPase activity for more than 100%, while Mg2+-ATPase activity reminded unaffected. We propose that this stimulation of enzyme activity was a consequence of an increase of the active surface of membranes.Physical chemistry 2012 : 11th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 24-28 September 201

pH dependent kinetics of [PdCl(dien)]+ reaction with some amino acids in the presence of SDS

We examined the micellar effects on the mechanisms of complex formation between [PdCl(dien)]Cl and amino acids L-cysteine and Gluthathione in the pH range from 0.5 to 3.5. In the presence 1×10-2 M sodium dodecyl sulphate micelles (SDS) the strongest effect on the reaction rate around pH 2 was observed.Physical chemistry 2004 : 7th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 21-23 September 200

Photochemical degradation of digoxin tested by Na,K-ATPase activity

The photochemical degradation of digoxin aqueous solution was obtained by Xelamp irradiation. The concentrations of digoxin in irradiated solutions were detected by measurements of Na,K-ATPase activity and by HPLC analysis. The excellent agreement using two independent methods for determination of digoxin concentration in the irradiated samples was achieved.Physical chemistry 2004 : 7th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 21-23 September 200

The influence of diazinon and its metabolites on acetylcholinesterase, NA+/K+-ATPase and antioxidant enzymes in rat brain synaptosomes

The aim of this study was to investigate neurotoxic potential and oxidative stress responses of diazinon and its metabolites, diazoxon and 2-isopropyl-6-methyl-4-pyrimidinol using synaptosomes as a model system. Synaptosomes were isolated from the brain of Wistar albino rats and incubated at 37oC for 1 hour in the presence of selected concentrations of the investigated compounds. Acetylcholinesterase, Na+/K+-ATPase and antioxidant enzymes activities were determined by standard spectrophotometric methods. Diazinon induced concentration-dependent acetylcholinesterase and Na+/K+-ATPase inhibition, while the activity of catalase, superoxide dismutase and glutathione peroxidase was not significantly affected. Increasing concentrations of diazoxon, oxo analog of diazinon, caused almost complete acetylcholinesterase and Na+/K+-ATPase inhibition, and activated antioxidant enzymes: catalase (up to 25%), superoxide dismutase (up to 55%) and glutathione peroxidase (up to 30%). Unlike diazoxon, diazinon hydrolysis product, 2-isopropyl-6-methyl-4-pyrimidinol did not remarkably change the activities of the investigated enzymes, except superoxide dismutase that was stimulated up to 25%. The obtained results suggest that neurotoxic and prooxidative potential of diazinon, thioorganophoshate used as a commercial insecticide preparation, significantly reinforces mostly due to its transformation to diazoxon in the metabolic pathways.Third International Conferenceon Radiation and Applications in Various Fields of Research, RAD 2015, June8-12, 2015, Budva, Montenegr

Electrochemical investigation of imidazol azo chromotropic acid and its Pd(II) complex

The electrochemical behaviour of 1,8-dihydroxy-2-(imidazol-2-ylazo)- naphthalene-3,6-disulphonic acid (IACA) and its complex with Pd(II) was investigated using cyclic voltammetry. Experiments were performed in the concentration range from 5×10-6M to 4.8 ×10-4M of IACA. Linear dependence of current intensity vs. IACA concentration was obtained in the investigated concentration range. According to the obtained results, process is controlled by diffusion.Physical chemistry 2004 : 7th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 21-23 September 200

Characterization and utilization of the permeate and retentate obtained after “dead-end” ultrafiltration

In the recent years, with the increase in bioethanol production, the increasing amounts of distillery wastewater are generated. Such wastewater (stillage) is one of the most polluted waste product of the food and beverage industries. The present study evaluates the treatment of distillery wastewater by ultrafiltration (UF), in order to reduce its pollution and evaluate the composition of the permeate and retentate. Polyethersulfone ultrafiltration membrane with molecular weight cut-off (MWCO) 30000 Da, was used for the experiments. The UF was carried out in dead-end mode. The results of the analyses of the permeate and retentate obtained after ultrafiltration were considered as well as different ways for their further utilization. The pollutant level in the permeate was decreased significantly in comparison to the raw stillage, and suspended solids were completely removed from the stillage. [Projekat Ministarstva nauke Republike Srbije, br. TR 31002

Mechanism of complex formation between [AuCl4] – and L-methionine

The kinetics of the reaction between tetrachloroaurate(III) ion and L-methionine has been studied spectrophotometrically by using stopped-flow technique in 0.1 M HClO4 as the function of temperature. The fast reaction was ascribed to the formation of short living square-planar [AuCl2Met]+ complex ion, that was reduced in the slower reaction step. The activation parameters (∆H≠ and ∆S≠ ) for complex formation were determined. The entropy of activation was compatible with an associative reaction mechanismPhysical chemistry 2006 : 8th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 26-29 September 200

Sorption-spectrophotometric method for the determination of Pd(II) in aqueous solutions

The reaction of Pd(II) with 1,8-dihydroxy-2-(prazol-5-ylazo)-naphthalene- 3-6-disulphonic acid (PACA) sorbed onto Dowex 1-X8 ion-exchange resin was investigated with the aim of developing an absorption-spectrophotometric analytical method for the determination of low Pd(II) concentrations in water. The immobilized reagent formed a 1:1 complex with Pd(II) having an absorption maximum at 650 nm. Parameters, such as pH, wavelength and contact time were optimised for a liven amount of the sorbed reagent. The linearity range of absorbance vs. Pd(II) concentration extended from 5x10(-6)- 5x 10(-5) M, 5x 10(-7) - 5x10(-6) and 2.5x 10(-8)-2.5x10(-7) M when using 10, 100 and 200 ml of sample solution. respectively. With a 200 ml sample, the detection limit was 2.5x10(-7) M Pd(II). Most metals, except Cu(II). did not interfere when present in tip to 100 times the concentration of Pd(II)