Time – dependent inhibition of electric eel ache induced by chlorpyrifos

The aim of the work was to investigate the influence of contact time between acetylcholinesterase (AChE) and chlorpyrifos, on the sensitivity of earlier developed AChE based bioanalytical method for detection and determination of organophosphates in water samples. The IC50 values were obtained from the concentration- dependent responses of AChE activity to chlorpyrifos and they decreased with the increasing the contact time. The results indicated that the sensitivity of AChE based bioassay can be improved by increasing the time of incubation, but this comes at the expense of additional analysis time. In addition, the inhibition parameters of chlorpyrifos induced inhibition of AChE were determined.Physical chemistry 2008 : 9th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 24-28 September 200

Temperature and Al3+ influence on electrophoretic mobility of porcine pepsin

The influence of temperature and different concentrations of Al3+ on pepsin electrophoretic mobility was investigated. The increase of Al3+ concentrations causes the decrease the electrophoretic mobility of enzyme. Also the increase of temperature induced the same effect. The influence of both temperature and Al3+ ion concentrations is additive.Physical chemistry 2006 : 8th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 26-29 September 200

Non-essential activation of pepsin by Al3+ “in vitro”

The in vitro effect of Al3+ ions on pepsin activity at pH 2, via kinetic parameters was evaluated. Kinetic study showed that Al3+ ions increase the maximal velocity (Vmax) rather than apparent affinity for substrate (KS) implying the non-competitive nature of activation which indicated that aluminium was a non-essential activator of partial non-competitive type.Physical chemistry 2008 : 9th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 24-28 September 200

The influence of Fe(III) incorporation on anti-cancer potential of a Wells-Dawson nanocluster

The objective of this study was to evaluate in vitro the antitumor properties of Fe(III)- substituted monolacunary Wells-Dawson polyoxotungstate, K7[FeIII(α2-P2W17O61)(H2O)] (FeWD) using cervical carcinoma HeLa cells as a model system. HeLa cells were exposed in vitro to FeWD within the concentration range from 0.001 to 1 mM, for 24, 48, and 72 hours. The studied Fe(III)- substituted polyoxotungstate affected HeLa cell viability in a concentration- and time-dependent manner. The obtained IC50 values (µM), as an indicator of the cytotoxic potential of FeWD, were: 16.64 ± 0.49, 10.75 ± 0.97, and 9.64 ± 0.19 for 24-, 48-, and 72-hour treatment, respectively. FeWD exhibited a stronger antitumor potential against HeLa cells than the structurally similar monolacunary Wells-Dawson polyoxotungstate, K10P2W17O61.20H2O (lacunary WD). Lacunary WD achieved IC50 at 24,11 µM after 24-hour exposure, which is about 44% higher concentration compared to the corresponding IC50 obtained for FeWD. This indicates that incorporating Fe(III) might be a new strategy for improving the antitumor efficacy of polyoxometalates as promising candidates for next-generation chemotherapeutics.ICCBIKG 2023 : 2nd International Conference on Chemo and Bioinformatics, 28-29 September 2023, Kragujevac, Serbi

In vitro cytotoxic activity of a monolacunary Wells-Dawson nanocluster against cervical carcinoma HeLa cells

The aim of this study was to assess in vitro cytotoxic activity of a monolacunary Wells- Dawson nanocluster, α2-K10P2W17O61.20H2O (lacunary WD) against cervical carcinoma HeLa cells as a commonly used model system for the evaluation of antitumor properties. After HeLa cells had been exposed to the investigated polyoxotungstate (the concentration range of 0.001 - 1 mM) for 24, 48, and 72 h, relative cell viability (expressed as a percentage of control) was determined. The obtained results showed that lacunary WD affected HeLa cell viability in a concentration- and time-dependent manner. IC50 values (in μM), calculated using sigmoidal fitting experimental plots, were as follows: 24.11 ± 9.95, 12.74 ± 0.096, and 11.48 ± 0.12 for 24, 48, and 72 hours treatment, respectively. In comparison with cisplatin, (positive control), IC50 values (μM) for 24 hours treatment were similar – 24.11 (lacunary WD) vs. 24.49 (cisplatin). However, after 48 and 72 hours IC50 obtained for cisplatin were found to be lower – 8.81 and 4.93 μM, respectively. Accordingly, the studied WD polyoxotungstate could not be regarded as a superior anticancer agent in comparison with the standard chemotherapeutic. Nevertheless, this studied nanocluster deserves attention as a promising antitumor therapeutic and as a good platform for the design of next-generation metal-based anticancer agents.ICCBIKG 2023 : 2nd International Conference on Chemo and Bioinformatics, 28-29 September 2023, Kragujevac, Serbi

Inhibition of ache by malathion and some structuraly similar compounds

Inhibition of bovine serum acetylcholinesterase by in vitro exposure to malathion, malaoxon, isomalathion and diethyl maleate was investigated to elucidate the mechanism of the enzyme interaction with structurally similar organophosphorus compounds. IC50 (half maximum inhibitory concentrations) were determined by Hill analysis of experimentally obtained inhibition curves. The values (2.87 ± 0.24)x10-6 M, (2.65±0.61)x10-6M, (3.01±0.36)x10-4 M and (5.69 ±0.7)x10-2 M were obtained for malaoxon, isomalathion, malathion and their hydrolysis product diethyl maleate, respectively. The relationship between the structure of the compounds and their potency to inhibit the enzyme activity was discussed.Physical chemistry 2006 : 8th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 26-29 September 200

The influence of Al3+ion on porcine pepsin activity in vitro

The in vitro effect of Al3+ ions in the concentration range 1.710-6M-8.710-3M on pepsin activity at pH 2, via kinetic parameters and its electrophoretic mobility was evaluated. Kinetic study demonstrated the existence of an activation effect of Al3+ at pH 2 on pepsin molecule. Kinetic analysis with respect to concentrations of haemoglobin showed that Al3+ ions increase the maximal velocity (Vmax) and kcat values rather than apparent affinity for substrate (KS) implying the non-competitive nature of activation which indicated that aluminium was a non-essential activator of partial non-competitive type. The values of the equilibrium constants KS and KmA for dissociation of corresponding complexes were evaluated as 0.9040.083mM and 8.560.51M, respectively. Dissociation constant KA, of activator from enzyme-activator complex calculated via kinetic and direct measurement of Al3+ binding data, as well as activation constant A50, the activator concentration that gives a rate equal to half at a saturating concentration of activator, were found to be 8.820.90M, 8.390.76M, and 8.050.48M respectively. Native PAGE electrophoresis shows the decrease in electrophoretic mobility of pepsin and confirms modification of the electric charge and conformational changes of pepsin caused by bound Al3+ on the pepsin molecule. Al3+ induced conformational changes of pepsin were verified by UV-VIS and IR spectra. Moreover, the absence of conformational changes in the haemoglobin molecule in the presence of Al3+ ions confirms that the obtained activation is a consequence of conformational changes caused only in the pepsin molecule

The influence of Al3+ion on porcine pepsin activity in vitro

The in vitro effect of Al3+ ions in the concentration range 1.710-6M-8.710-3M on pepsin activity at pH 2, via kinetic parameters and its electrophoretic mobility was evaluated. Kinetic study demonstrated the existence of an activation effect of Al3+ at pH 2 on pepsin molecule. Kinetic analysis with respect to concentrations of haemoglobin showed that Al3+ ions increase the maximal velocity (Vmax) and kcat values rather than apparent affinity for substrate (KS) implying the non-competitive nature of activation which indicated that aluminium was a non-essential activator of partial non-competitive type. The values of the equilibrium constants KS and KmA for dissociation of corresponding complexes were evaluated as 0.9040.083mM and 8.560.51M, respectively. Dissociation constant KA, of activator from enzyme-activator complex calculated via kinetic and direct measurement of Al3+ binding data, as well as activation constant A50, the activator concentration that gives a rate equal to half at a saturating concentration of activator, were found to be 8.820.90M, 8.390.76M, and 8.050.48M respectively. Native PAGE electrophoresis shows the decrease in electrophoretic mobility of pepsin and confirms modification of the electric charge and conformational changes of pepsin caused by bound Al3+ on the pepsin molecule. Al3+ induced conformational changes of pepsin were verified by UV-VIS and IR spectra. Moreover, the absence of conformational changes in the haemoglobin molecule in the presence of Al3+ ions confirms that the obtained activation is a consequence of conformational changes caused only in the pepsin molecule

Modulation of acetylcholinesterase activity induced by polyoxotungstates

The in vitroinfluence of five polyoxotungstates containing various central atoms on acetylcholinesterase (AChE) activity was investigated. K6[PV3W9O40] × 3H2O, K6H2[TiW11CoO40] × 13H2O, (NH4)14[NaP5W30O110] × 31H2O, K7[SiV3W9O40] × 10H2O, and K7[Ti2PW10O40] induced the enzyme inhibition in a concentration-dependent manner. Inhibitory power of the investigated compounds was evaluated using IC50values. K7[SiV3W9O40] × 10H2O affected AChE activity with lowest potency (IC50 = 4.80 × 10-4mol/L). K6H2[TiW11CoO40] × 13H2O and K7[Ti2PW10O40] exhibited high affinity toward the enzyme, inducing half-maximuminhibition at micromolar concentrations (1.14 × 10-6and 1.04 × 10-6mol/L, respectively), while the same effect was achieved in the presence of about fifty times higher concentration of K6[PV3W9O40] × 3H2O. Finally, (NH4)14[NaP5W30O110] × 31H2O was foundas the most potent inhibitor of AChE activity (IC50 = 6.36 × 10-7mol/L), and consequently the most promising candidate for the treatment of neurological diseases associated with acetylcholine leakage.Physical chemistry 2016 : 13th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 26-30 September 2016

In vitro evaluation of diazinon and its degradation products neurotoxicity potential in rat brain synaptosomes

Toxic effects of diazinon and its degradation products, diazoxon and 2- isopropyl-6-methyl-4-pyrimidinol (IMP), were investigated in vitro by determining the inhibition of acetylcholinesterase (AChE), Na+ /K+ -ATPase and ecto-ATPase activity in rat brain synaptosomes after 1 hour exposure toward varying concentrations. Dose-dependent AChE and Na+ /K+ -ATPase inhibition was obtained in the presence of diazinon, while diazinon concentrations below 0.1 mM did not noticeably affect ecto-ATPase activity. Diazinon oxidation product, diazoxon was found as the most toxic investigated compound. Diazoxon induced dose-dependent and almost complete inhibition of AChE, Na+ /K+ -ATPase and ecto-ATPase at the highest investigated concentration (0.1 mM), while hydrolysis product of diazinon, IMP did not remarkably influence their activities