TY  - JOUR
AU  - Vujačić Nikezić, Ana V.
AU  - Janjić, Goran
AU  - Bondžić, Aleksandra M.
AU  - Zarić, Božidarka
AU  - Vasic-Anicijevic, Dragana D.
AU  - Momic, Tatjana G.
AU  - Vasić, Vesna M.
PY  - 2018
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/2452
AB  - The present paper deals with investigation of the interaction between selected simple structure Au(iii) ([AuCl4](-), [AuCl2(dmso)(2)](+), [AuCl2(bipy)](+)) and Pt(ii) ([PtCl2(dmso)(2)]) complexes with Na/K-ATPase as the target enzyme, using an experimental and theoretical approach. Reaction stoichiometries and binding constants for these enzyme/complex systems were determined, while kinetic measurements were used in order to reveal the type of inhibition. Based on the results obtained by quantum mechanical calculations (electrostatic surface potential (ESP), volume and surface of the complexes) the nature of the investigated complexes was characterized. By using the solvent accessible surface area (SASA) applied on specific inhibitory sites (ion channel and intracellular domains) the nature of these sites was described. Docking studies were used to determine the theoretical probability of the non-covalent metal binding site positions. Inhibition studies implied that all the investigated complexes decreased the activity of the enzyme while the kinetic analysis indicated an uncompetitive mode of inhibition for the selected complexes. Docking results suggested that the main inhibitory site of all these complexes is located in the ion translocation pathway on the extracellular side in the E2P enzyme conformation, similar to the case of cardiac glycosides, specific Na/K-ATPase inhibitors. Also, based on our knowledge, the hydrolyzed forms of [AuCl4](-) and [PtCl2(dmso)(2)] complexes were investigated for the first time by theoretical calculations in this paper. Thereby, a new inhibitory site situated between the M2 and M4 helices was revealed. Binding in this site induces conformational changes in the enzyme domains and perturbs the E1-E2P conformational equilibrium, causing enzyme inhibition.
PB  - Royal Soc Chemistry, Cambridge
T2  - Metallomics
T1  - Interaction of Au(iii) and Pt(ii) complexes with Na/K-ATPase: experimental and theoretical study of reaction stoichiometry and binding sites
VL  - 10
IS  - 7
SP  - 1003
EP  - 1015
DO  - 10.1039/c8mt00111a
ER  - 

@article{
author = "Vujačić Nikezić, Ana V. and Janjić, Goran and Bondžić, Aleksandra M. and Zarić, Božidarka and Vasic-Anicijevic, Dragana D. and Momic, Tatjana G. and Vasić, Vesna M.",
year = "2018",
abstract = "The present paper deals with investigation of the interaction between selected simple structure Au(iii) ([AuCl4](-), [AuCl2(dmso)(2)](+), [AuCl2(bipy)](+)) and Pt(ii) ([PtCl2(dmso)(2)]) complexes with Na/K-ATPase as the target enzyme, using an experimental and theoretical approach. Reaction stoichiometries and binding constants for these enzyme/complex systems were determined, while kinetic measurements were used in order to reveal the type of inhibition. Based on the results obtained by quantum mechanical calculations (electrostatic surface potential (ESP), volume and surface of the complexes) the nature of the investigated complexes was characterized. By using the solvent accessible surface area (SASA) applied on specific inhibitory sites (ion channel and intracellular domains) the nature of these sites was described. Docking studies were used to determine the theoretical probability of the non-covalent metal binding site positions. Inhibition studies implied that all the investigated complexes decreased the activity of the enzyme while the kinetic analysis indicated an uncompetitive mode of inhibition for the selected complexes. Docking results suggested that the main inhibitory site of all these complexes is located in the ion translocation pathway on the extracellular side in the E2P enzyme conformation, similar to the case of cardiac glycosides, specific Na/K-ATPase inhibitors. Also, based on our knowledge, the hydrolyzed forms of [AuCl4](-) and [PtCl2(dmso)(2)] complexes were investigated for the first time by theoretical calculations in this paper. Thereby, a new inhibitory site situated between the M2 and M4 helices was revealed. Binding in this site induces conformational changes in the enzyme domains and perturbs the E1-E2P conformational equilibrium, causing enzyme inhibition.",
publisher = "Royal Soc Chemistry, Cambridge",
journal = "Metallomics",
title = "Interaction of Au(iii) and Pt(ii) complexes with Na/K-ATPase: experimental and theoretical study of reaction stoichiometry and binding sites",
volume = "10",
number = "7",
pages = "1003-1015",
doi = "10.1039/c8mt00111a"
}

Vujačić Nikezić, A. V., Janjić, G., Bondžić, A. M., Zarić, B., Vasic-Anicijevic, D. D., Momic, T. G.,& Vasić, V. M.. (2018). Interaction of Au(iii) and Pt(ii) complexes with Na/K-ATPase: experimental and theoretical study of reaction stoichiometry and binding sites. in Metallomics
Royal Soc Chemistry, Cambridge., 10(7), 1003-1015.
https://doi.org/10.1039/c8mt00111a

Vujačić Nikezić AV, Janjić G, Bondžić AM, Zarić B, Vasic-Anicijevic DD, Momic TG, Vasić VM. Interaction of Au(iii) and Pt(ii) complexes with Na/K-ATPase: experimental and theoretical study of reaction stoichiometry and binding sites. in Metallomics. 2018;10(7):1003-1015.
doi:10.1039/c8mt00111a .

Vujačić Nikezić, Ana V., Janjić, Goran, Bondžić, Aleksandra M., Zarić, Božidarka, Vasic-Anicijevic, Dragana D., Momic, Tatjana G., Vasić, Vesna M., "Interaction of Au(iii) and Pt(ii) complexes with Na/K-ATPase: experimental and theoretical study of reaction stoichiometry and binding sites" in Metallomics, 10, no. 7 (2018):1003-1015,
https://doi.org/10.1039/c8mt00111a . .

TY  - JOUR
AU  - Bondžić, Aleksandra M.
AU  - Janjić, Goran
AU  - Dramićanin, Miroslav
AU  - Messori, Luigi
AU  - Massai, Lara
AU  - Parac-Vogt Tatjana
AU  - Vasić, Vesna M.
PY  - 2017
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/2179
AB  - Na/K-ATPase is emerging as an important target for a variety of anticancer metal-based drugs. The interactions of Na/K-ATPase (in its E1 state) with three representative and structurally related cytotoxic gold(III) complexes, i.e. [Au(bipy)(OH)(2)][PF6], bipy = 2,2'-bipyridine; [Au(py(dmb)-H)(CH3COO)(2)], py(dmb)-H = deprotonated 6-(1,1-dimethylbenzyl)-pyridine and [Au(bipy(dmb)-H)(OH)][PF6], bipy(c)-H = deprotonated 6-(1,1-dimethylbenzyl)-2,20-bipyridine, are investigated here in depth using a variety of spectroscopic methods, in combination with docking studies. Detailed information is gained on the conformational and structural changes experienced by the enzyme upon binding of these gold(III) complexes. The quenching constants of intrinsic enzyme fluorescence, the fraction of Trp residues accessible to gold(III) complexes and the reaction stoichiometries were determined in various cases. Specific hypotheses are made concerning the binding mode of these gold(III) complexes to the enzyme and the likely binding sites. Differences in their binding behaviour toward Na/K-ATPase are explained on the ground of their distinctive structural features. The present results offer further support to the view that Na/K-ATPase may be a relevant biomolecular target for cytotoxic gold(III) compounds of medicinal interest and may thus be involved in their overall mode of action.
PB  - Royal Soc Chemistry, Cambridge
T2  - Metallomics
T1  - Na/K-ATPase as a target for anticancer metal based drugs: insights into molecular interactions with selected gold(III) complexes
VL  - 9
IS  - 3
SP  - 292
EP  - 300
DO  - 10.1039/c7mt00017k
ER  - 

@article{
author = "Bondžić, Aleksandra M. and Janjić, Goran and Dramićanin, Miroslav and Messori, Luigi and Massai, Lara and Parac-Vogt Tatjana and Vasić, Vesna M.",
year = "2017",
abstract = "Na/K-ATPase is emerging as an important target for a variety of anticancer metal-based drugs. The interactions of Na/K-ATPase (in its E1 state) with three representative and structurally related cytotoxic gold(III) complexes, i.e. [Au(bipy)(OH)(2)][PF6], bipy = 2,2'-bipyridine; [Au(py(dmb)-H)(CH3COO)(2)], py(dmb)-H = deprotonated 6-(1,1-dimethylbenzyl)-pyridine and [Au(bipy(dmb)-H)(OH)][PF6], bipy(c)-H = deprotonated 6-(1,1-dimethylbenzyl)-2,20-bipyridine, are investigated here in depth using a variety of spectroscopic methods, in combination with docking studies. Detailed information is gained on the conformational and structural changes experienced by the enzyme upon binding of these gold(III) complexes. The quenching constants of intrinsic enzyme fluorescence, the fraction of Trp residues accessible to gold(III) complexes and the reaction stoichiometries were determined in various cases. Specific hypotheses are made concerning the binding mode of these gold(III) complexes to the enzyme and the likely binding sites. Differences in their binding behaviour toward Na/K-ATPase are explained on the ground of their distinctive structural features. The present results offer further support to the view that Na/K-ATPase may be a relevant biomolecular target for cytotoxic gold(III) compounds of medicinal interest and may thus be involved in their overall mode of action.",
publisher = "Royal Soc Chemistry, Cambridge",
journal = "Metallomics",
title = "Na/K-ATPase as a target for anticancer metal based drugs: insights into molecular interactions with selected gold(III) complexes",
volume = "9",
number = "3",
pages = "292-300",
doi = "10.1039/c7mt00017k"
}

Bondžić, A. M., Janjić, G., Dramićanin, M., Messori, L., Massai, L., Parac-Vogt Tatjana,& Vasić, V. M.. (2017). Na/K-ATPase as a target for anticancer metal based drugs: insights into molecular interactions with selected gold(III) complexes. in Metallomics
Royal Soc Chemistry, Cambridge., 9(3), 292-300.
https://doi.org/10.1039/c7mt00017k

Bondžić AM, Janjić G, Dramićanin M, Messori L, Massai L, Parac-Vogt Tatjana, Vasić VM. Na/K-ATPase as a target for anticancer metal based drugs: insights into molecular interactions with selected gold(III) complexes. in Metallomics. 2017;9(3):292-300.
doi:10.1039/c7mt00017k .

Bondžić, Aleksandra M., Janjić, Goran, Dramićanin, Miroslav, Messori, Luigi, Massai, Lara, Parac-Vogt Tatjana, Vasić, Vesna M., "Na/K-ATPase as a target for anticancer metal based drugs: insights into molecular interactions with selected gold(III) complexes" in Metallomics, 9, no. 3 (2017):292-300,
https://doi.org/10.1039/c7mt00017k . .

TY  - JOUR
AU  - Bondžić, Aleksandra M.
AU  - Čolović, Mirjana B.
AU  - Janjić, Goran
AU  - Zarić, Božidarka
AU  - Petrović, Sandra
AU  - Krstic, Danijela Z.
AU  - Marzo, Tiziano
AU  - Messori, Luigi
AU  - Vasić, Vesna M.
PY  - 2017
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/2143
AB  - The in vitro effects of oxo-bridged binuclear gold(III) complexes, i.e., [(bipy2Me)(2)Au-2(mu-O)(2)][PF6](2) (Auoxo6), Au-2[(bipydmb-H)(2)(mu-O)][PF6] (Au(2)bipyC) and [Au-2(phen(2Me))(2)(mu-O)(2)](PF6)(2) (Au(2)phen) on Na/K-ATPase, purified from the porcine cerebral cortex, were investigated. All three studied gold complexes inhibited the enzyme activity in a concentration-dependent manner achieving IC50 values in the low micromolar range. Kinetic analysis suggested an uncompetitive mode of inhibition for Auoxo6 and Au(2)bipyC, and a mixed type one for Au(2)phen. Docking studies indicated that the inhibitory actions of all tested complexes are related to E2-P enzyme conformation binding to ion channel and intracellular part between N and P sub-domain. In addition, Au(2)phen was able to inhibit the enzyme by interacting with its extracellular part as well. Toxic effects of the gold(III) complexes were evaluated in vitro by following lactate dehydrogenase activity in rat brain synaptosomes and incidence of micronuclei and cytokinesis-block proliferation index in cultivated human lymphocytes. All investigated complexes turned out to induce cytogenetic damage consisting of a significant decrease in cell proliferation and an increase in micronuclei in a dose-dependent manner. On the other hand, lactate dehydrogenase activity, an indicator of membrane integrity/viability, was not affected by Auoxo6 and Au(2)bipyC, while Au(2)phen slightly modified its activity.
PB  - Springer, New York
T2  - Journal of Biological Inorganic Chemistry
T1  - The influence of oxo-bridged binuclear gold(III) complexes on Na/K-ATPase activity: a joint experimental and theoretical approach
VL  - 22
IS  - 6
SP  - 819
EP  - 832
DO  - 10.1007/s00775-017-1460-5
ER  - 

@article{
author = "Bondžić, Aleksandra M. and Čolović, Mirjana B. and Janjić, Goran and Zarić, Božidarka and Petrović, Sandra and Krstic, Danijela Z. and Marzo, Tiziano and Messori, Luigi and Vasić, Vesna M.",
year = "2017",
abstract = "The in vitro effects of oxo-bridged binuclear gold(III) complexes, i.e., [(bipy2Me)(2)Au-2(mu-O)(2)][PF6](2) (Auoxo6), Au-2[(bipydmb-H)(2)(mu-O)][PF6] (Au(2)bipyC) and [Au-2(phen(2Me))(2)(mu-O)(2)](PF6)(2) (Au(2)phen) on Na/K-ATPase, purified from the porcine cerebral cortex, were investigated. All three studied gold complexes inhibited the enzyme activity in a concentration-dependent manner achieving IC50 values in the low micromolar range. Kinetic analysis suggested an uncompetitive mode of inhibition for Auoxo6 and Au(2)bipyC, and a mixed type one for Au(2)phen. Docking studies indicated that the inhibitory actions of all tested complexes are related to E2-P enzyme conformation binding to ion channel and intracellular part between N and P sub-domain. In addition, Au(2)phen was able to inhibit the enzyme by interacting with its extracellular part as well. Toxic effects of the gold(III) complexes were evaluated in vitro by following lactate dehydrogenase activity in rat brain synaptosomes and incidence of micronuclei and cytokinesis-block proliferation index in cultivated human lymphocytes. All investigated complexes turned out to induce cytogenetic damage consisting of a significant decrease in cell proliferation and an increase in micronuclei in a dose-dependent manner. On the other hand, lactate dehydrogenase activity, an indicator of membrane integrity/viability, was not affected by Auoxo6 and Au(2)bipyC, while Au(2)phen slightly modified its activity.",
publisher = "Springer, New York",
journal = "Journal of Biological Inorganic Chemistry",
title = "The influence of oxo-bridged binuclear gold(III) complexes on Na/K-ATPase activity: a joint experimental and theoretical approach",
volume = "22",
number = "6",
pages = "819-832",
doi = "10.1007/s00775-017-1460-5"
}

Bondžić, A. M., Čolović, M. B., Janjić, G., Zarić, B., Petrović, S., Krstic, D. Z., Marzo, T., Messori, L.,& Vasić, V. M.. (2017). The influence of oxo-bridged binuclear gold(III) complexes on Na/K-ATPase activity: a joint experimental and theoretical approach. in Journal of Biological Inorganic Chemistry
Springer, New York., 22(6), 819-832.
https://doi.org/10.1007/s00775-017-1460-5

Bondžić AM, Čolović MB, Janjić G, Zarić B, Petrović S, Krstic DZ, Marzo T, Messori L, Vasić VM. The influence of oxo-bridged binuclear gold(III) complexes on Na/K-ATPase activity: a joint experimental and theoretical approach. in Journal of Biological Inorganic Chemistry. 2017;22(6):819-832.
doi:10.1007/s00775-017-1460-5 .

Bondžić, Aleksandra M., Čolović, Mirjana B., Janjić, Goran, Zarić, Božidarka, Petrović, Sandra, Krstic, Danijela Z., Marzo, Tiziano, Messori, Luigi, Vasić, Vesna M., "The influence of oxo-bridged binuclear gold(III) complexes on Na/K-ATPase activity: a joint experimental and theoretical approach" in Journal of Biological Inorganic Chemistry, 22, no. 6 (2017):819-832,
https://doi.org/10.1007/s00775-017-1460-5 . .

TY  - JOUR
AU  - Nastasijevic, Branislav
AU  - Milošević, Maja
AU  - Janjić, Goran
AU  - Stanić, Vojislav
AU  - Vasić, Vesna
PY  - 2016
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/1857
AB  - The extracellular nucleotides act as neurotransmitters and signaling molecules in CNS, binding to a P2X and P2Y receptors. Their concentration regulates a cascade of membrane ecto enzymes, including the ecto-nucleotide triphosphate diphosphohydrolases (E-NTPDases). In many neuropathological conditions, such as neuroinflammatory, epilepsy, depression and migraine, altering of E-NTPDase activity was observed. The objective of this study was to investigate whether Gentiana lutea (G. lutea) extracts affect E-NTPDase activity and which of their constituents (loganic acid, gentiopicroside, isovitexin, amarogentin and isogentisin) exert inhibitory activity. The constituent's concentration in the extracts was determined by ultra performance liquid chromatography coupled with mass spectrometry (UPLC-MS). Extracts and constituents were tested with E-NTPDase displayed on the rat synaptosomal membrane as well as by molecular docking study. Ethanol water extract (50%, v/v) exerted significant level of inhibition (52%) at concentration of 200 mg mL(-1). By inhibition studies with single constituents about 30% inhibition was achieved in any case, thus the model of one substrate acting on two enzymes was used to determine IC50 values. Molecular docking study revealed amarogentin, isovitexin and isogentisin dimer as the potent E-NTPDase inhibitors with the binding energies ranging from -9.4 to -10 kcal mol(-1) versus -8.0 kcal mol(-1) for ATP. Presence of isogentisin only in ethanol water extracts may explain their better inhibitory acitivities. Findings of this study are useful from the perspective of safety of products based on G. lutea extracts, while investigated constituents belong to secoiridoids and xanthones class of compounds could be considered as a source of potential E-NTPDase inhibitors.
PB  - Asian Network Scientific Information-Ansinet, Faisalabad
T2  - International Journal of Pharmacology
T1  - Gentiana lutea Extracts and their Constituents as Inhibitors of Synaptosomal Ecto-NTPDase
VL  - 12
IS  - 4
SP  - 272
EP  - 289
DO  - 10.3923/ijp.2016.272.289
ER  - 

@article{
author = "Nastasijevic, Branislav and Milošević, Maja and Janjić, Goran and Stanić, Vojislav and Vasić, Vesna",
year = "2016",
abstract = "The extracellular nucleotides act as neurotransmitters and signaling molecules in CNS, binding to a P2X and P2Y receptors. Their concentration regulates a cascade of membrane ecto enzymes, including the ecto-nucleotide triphosphate diphosphohydrolases (E-NTPDases). In many neuropathological conditions, such as neuroinflammatory, epilepsy, depression and migraine, altering of E-NTPDase activity was observed. The objective of this study was to investigate whether Gentiana lutea (G. lutea) extracts affect E-NTPDase activity and which of their constituents (loganic acid, gentiopicroside, isovitexin, amarogentin and isogentisin) exert inhibitory activity. The constituent's concentration in the extracts was determined by ultra performance liquid chromatography coupled with mass spectrometry (UPLC-MS). Extracts and constituents were tested with E-NTPDase displayed on the rat synaptosomal membrane as well as by molecular docking study. Ethanol water extract (50%, v/v) exerted significant level of inhibition (52%) at concentration of 200 mg mL(-1). By inhibition studies with single constituents about 30% inhibition was achieved in any case, thus the model of one substrate acting on two enzymes was used to determine IC50 values. Molecular docking study revealed amarogentin, isovitexin and isogentisin dimer as the potent E-NTPDase inhibitors with the binding energies ranging from -9.4 to -10 kcal mol(-1) versus -8.0 kcal mol(-1) for ATP. Presence of isogentisin only in ethanol water extracts may explain their better inhibitory acitivities. Findings of this study are useful from the perspective of safety of products based on G. lutea extracts, while investigated constituents belong to secoiridoids and xanthones class of compounds could be considered as a source of potential E-NTPDase inhibitors.",
publisher = "Asian Network Scientific Information-Ansinet, Faisalabad",
journal = "International Journal of Pharmacology",
title = "Gentiana lutea Extracts and their Constituents as Inhibitors of Synaptosomal Ecto-NTPDase",
volume = "12",
number = "4",
pages = "272-289",
doi = "10.3923/ijp.2016.272.289"
}

Nastasijevic, B., Milošević, M., Janjić, G., Stanić, V.,& Vasić, V.. (2016). Gentiana lutea Extracts and their Constituents as Inhibitors of Synaptosomal Ecto-NTPDase. in International Journal of Pharmacology
Asian Network Scientific Information-Ansinet, Faisalabad., 12(4), 272-289.
https://doi.org/10.3923/ijp.2016.272.289

Nastasijevic B, Milošević M, Janjić G, Stanić V, Vasić V. Gentiana lutea Extracts and their Constituents as Inhibitors of Synaptosomal Ecto-NTPDase. in International Journal of Pharmacology. 2016;12(4):272-289.
doi:10.3923/ijp.2016.272.289 .

Nastasijevic, Branislav, Milošević, Maja, Janjić, Goran, Stanić, Vojislav, Vasić, Vesna, "Gentiana lutea Extracts and their Constituents as Inhibitors of Synaptosomal Ecto-NTPDase" in International Journal of Pharmacology, 12, no. 4 (2016):272-289,
https://doi.org/10.3923/ijp.2016.272.289 . .

TY  - JOUR
AU  - Bondžić, Aleksandra M.
AU  - Lazarević-Pašti, Tamara D.
AU  - Bondžić, Bojan
AU  - Čolović, Mirjana B.
AU  - Jadranin, Milka
AU  - Vasić, Vesna M.
PY  - 2013
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/1293
AB  - The aim of the present paper was to investigate the reaction of quercetin, the flavonol very often used as a dietary supplement, with [AuCl4](-) ions. The reaction was studied spectrophotometrically using the equimolar solutions in 1 : 1 water-methanol at pH similar to 2. The spectrophotometric data indicated the formation of the products with an absorption maximum at 295 nm in all cases, characteristic of the oxidized forms of quercetin. HPLC coupled with DAD and LC-MS analysis of the reaction products suggested that the oxidation of quercetin resulted in the generation of similar metabolites including quinone and various oxidized quercetin-solvent adducts. In addition, cyclic voltammetric measurements confirmed that under applied experimental conditions, the reduction of Au(III) to Au(0) took place. The reduction species in the reaction mixture were Au(III) ions, while Au(I) disproportionates back to Au(III) and Au(0). The newly generated Au(III) ions further oxidized 3'-4'-dihydroxy groups of quercetin adducts obtained after first 2e(-) oxidation, giving the final reaction products. Based on the identification of reaction products, the reaction mechanism for the oxidation of quercetin in the presence of Au(III) which involves two 2e(-) transfer processes was proposed.
PB  - Royal Soc Chemistry, Cambridge
T2  - New Journal of Chemistry
T1  - Investigation of reaction between quercetin and Au(III) in acidic media: mechanism and identification of reaction products
VL  - 37
IS  - 4
SP  - 901
EP  - 908
DO  - 10.1039/c2nj40742f
ER  - 

@article{
author = "Bondžić, Aleksandra M. and Lazarević-Pašti, Tamara D. and Bondžić, Bojan and Čolović, Mirjana B. and Jadranin, Milka and Vasić, Vesna M.",
year = "2013",
abstract = "The aim of the present paper was to investigate the reaction of quercetin, the flavonol very often used as a dietary supplement, with [AuCl4](-) ions. The reaction was studied spectrophotometrically using the equimolar solutions in 1 : 1 water-methanol at pH similar to 2. The spectrophotometric data indicated the formation of the products with an absorption maximum at 295 nm in all cases, characteristic of the oxidized forms of quercetin. HPLC coupled with DAD and LC-MS analysis of the reaction products suggested that the oxidation of quercetin resulted in the generation of similar metabolites including quinone and various oxidized quercetin-solvent adducts. In addition, cyclic voltammetric measurements confirmed that under applied experimental conditions, the reduction of Au(III) to Au(0) took place. The reduction species in the reaction mixture were Au(III) ions, while Au(I) disproportionates back to Au(III) and Au(0). The newly generated Au(III) ions further oxidized 3'-4'-dihydroxy groups of quercetin adducts obtained after first 2e(-) oxidation, giving the final reaction products. Based on the identification of reaction products, the reaction mechanism for the oxidation of quercetin in the presence of Au(III) which involves two 2e(-) transfer processes was proposed.",
publisher = "Royal Soc Chemistry, Cambridge",
journal = "New Journal of Chemistry",
title = "Investigation of reaction between quercetin and Au(III) in acidic media: mechanism and identification of reaction products",
volume = "37",
number = "4",
pages = "901-908",
doi = "10.1039/c2nj40742f"
}

Bondžić, A. M., Lazarević-Pašti, T. D., Bondžić, B., Čolović, M. B., Jadranin, M.,& Vasić, V. M.. (2013). Investigation of reaction between quercetin and Au(III) in acidic media: mechanism and identification of reaction products. in New Journal of Chemistry
Royal Soc Chemistry, Cambridge., 37(4), 901-908.
https://doi.org/10.1039/c2nj40742f

Bondžić AM, Lazarević-Pašti TD, Bondžić B, Čolović MB, Jadranin M, Vasić VM. Investigation of reaction between quercetin and Au(III) in acidic media: mechanism and identification of reaction products. in New Journal of Chemistry. 2013;37(4):901-908.
doi:10.1039/c2nj40742f .

Bondžić, Aleksandra M., Lazarević-Pašti, Tamara D., Bondžić, Bojan, Čolović, Mirjana B., Jadranin, Milka, Vasić, Vesna M., "Investigation of reaction between quercetin and Au(III) in acidic media: mechanism and identification of reaction products" in New Journal of Chemistry, 37, no. 4 (2013):901-908,
https://doi.org/10.1039/c2nj40742f . .

TY  - JOUR
AU  - Lazarević-Pašti, Tamara D.
AU  - Momić, Tatjana
AU  - Onjia, Antonije E.
AU  - Vujisić, Ljubodrag V.
AU  - Vasić, Vesna
PY  - 2010
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/3176
AB  - In order to improve the sensitivity of assays for inhibitors of the enzyme acetylcholine esterase (AChE), an effective method was developed for the conversion of the organophosphate pesticides (OPs) diazinon, malathion, chlorpyrifos, azinphos-methyl and phorate into more toxic inhibitors. This was accomplished by converting them from the thio form into their oxo form using the enzyme myeloperoxidase. The oxo forms, which are the only products of conversion, were determined by AChE bioassays, using either the free enzyme, or a flow injection analysis manifold with immobilized AChE and spectrophotometric detection. All modified OPs exhibited inhibitory power at ppb levels and within 10 min. The method is considered to represent an excellent means for improving the sensitivity of assays for determination of OPs.
PB  - Springer Science and Business Media LLC
T2  - Microchimica Acta
T1  - Myeloperoxidase-mediated oxidation of organophosphorus pesticides as a pre-step in their determination by AChE based bioanalytical methods
VL  - 170
IS  - 3-4
SP  - 289
EP  - 297
DO  - 10.1007/s00604-010-0324-2
ER  - 

@article{
author = "Lazarević-Pašti, Tamara D. and Momić, Tatjana and Onjia, Antonije E. and Vujisić, Ljubodrag V. and Vasić, Vesna",
year = "2010",
abstract = "In order to improve the sensitivity of assays for inhibitors of the enzyme acetylcholine esterase (AChE), an effective method was developed for the conversion of the organophosphate pesticides (OPs) diazinon, malathion, chlorpyrifos, azinphos-methyl and phorate into more toxic inhibitors. This was accomplished by converting them from the thio form into their oxo form using the enzyme myeloperoxidase. The oxo forms, which are the only products of conversion, were determined by AChE bioassays, using either the free enzyme, or a flow injection analysis manifold with immobilized AChE and spectrophotometric detection. All modified OPs exhibited inhibitory power at ppb levels and within 10 min. The method is considered to represent an excellent means for improving the sensitivity of assays for determination of OPs.",
publisher = "Springer Science and Business Media LLC",
journal = "Microchimica Acta",
title = "Myeloperoxidase-mediated oxidation of organophosphorus pesticides as a pre-step in their determination by AChE based bioanalytical methods",
volume = "170",
number = "3-4",
pages = "289-297",
doi = "10.1007/s00604-010-0324-2"
}

Lazarević-Pašti, T. D., Momić, T., Onjia, A. E., Vujisić, L. V.,& Vasić, V.. (2010). Myeloperoxidase-mediated oxidation of organophosphorus pesticides as a pre-step in their determination by AChE based bioanalytical methods. in Microchimica Acta
Springer Science and Business Media LLC., 170(3-4), 289-297.
https://doi.org/10.1007/s00604-010-0324-2

Lazarević-Pašti TD, Momić T, Onjia AE, Vujisić LV, Vasić V. Myeloperoxidase-mediated oxidation of organophosphorus pesticides as a pre-step in their determination by AChE based bioanalytical methods. in Microchimica Acta. 2010;170(3-4):289-297.
doi:10.1007/s00604-010-0324-2 .

Lazarević-Pašti, Tamara D., Momić, Tatjana, Onjia, Antonije E., Vujisić, Ljubodrag V., Vasić, Vesna, "Myeloperoxidase-mediated oxidation of organophosphorus pesticides as a pre-step in their determination by AChE based bioanalytical methods" in Microchimica Acta, 170, no. 3-4 (2010):289-297,
https://doi.org/10.1007/s00604-010-0324-2 . .

TY  - JOUR
AU  - Vujačić, Ana V.
AU  - Savić, J.Z.
AU  - Sovilj, Sofija P.
AU  - Mészáros, Szécsényi K.
AU  - Todorović, Nina
AU  - Petković, M.Z.
AU  - Vasić, Vesna M.
PY  - 2009
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/601
AB  - The kinetics of the reaction between the tetrachloroaurate(III) ion and l-methionine (l-Met) (0.1 M HClO4, pH 1.0-2.5) have been studied spectrophotometrically using a stopped-flow technique at different temperatures. Initially, the fast substitution reaction was ascribed to the formation of the short-lived square-planar Au(III)-(l-Met) that was followed by the replacement of a Cl- ligand and a subsequent, slower reduction to Au(I)-(l-Met). This is an intermolecular process, involving attack on the [AuCl4]- complex by an outer-sphere l-methionine. The activation parameters (ΔH≠ and ΔS≠) for substitution and reduction were determined. IR spectroscopy indicates that l-methionine acts as a bidentate ligand, most likely coordinating via the S and N atoms, while 1H and 13C NMR data indicate methionine sulfoxide as the final product. Finally, the components of the reaction were treated thermally in order to investigate the solid phase synthesis of the resulting complex.
PB  - Oxford : Pergamon-Elsevier Science Ltd
T2  - Polyhedron
T1  - Mechanism of complex formation between [AuCl4]- and l-methionine
VL  - 28
IS  - 3
SP  - 593
EP  - 599
DO  - 10.1016/j.poly.2008.11.045
ER  - 

@article{
author = "Vujačić, Ana V. and Savić, J.Z. and Sovilj, Sofija P. and Mészáros, Szécsényi K. and Todorović, Nina and Petković, M.Z. and Vasić, Vesna M.",
year = "2009",
abstract = "The kinetics of the reaction between the tetrachloroaurate(III) ion and l-methionine (l-Met) (0.1 M HClO4, pH 1.0-2.5) have been studied spectrophotometrically using a stopped-flow technique at different temperatures. Initially, the fast substitution reaction was ascribed to the formation of the short-lived square-planar Au(III)-(l-Met) that was followed by the replacement of a Cl- ligand and a subsequent, slower reduction to Au(I)-(l-Met). This is an intermolecular process, involving attack on the [AuCl4]- complex by an outer-sphere l-methionine. The activation parameters (ΔH≠ and ΔS≠) for substitution and reduction were determined. IR spectroscopy indicates that l-methionine acts as a bidentate ligand, most likely coordinating via the S and N atoms, while 1H and 13C NMR data indicate methionine sulfoxide as the final product. Finally, the components of the reaction were treated thermally in order to investigate the solid phase synthesis of the resulting complex.",
publisher = "Oxford : Pergamon-Elsevier Science Ltd",
journal = "Polyhedron",
title = "Mechanism of complex formation between [AuCl4]- and l-methionine",
volume = "28",
number = "3",
pages = "593-599",
doi = "10.1016/j.poly.2008.11.045"
}

Vujačić, A. V., Savić, J.Z., Sovilj, S. P., Mészáros, S. K., Todorović, N., Petković, M.Z.,& Vasić, V. M.. (2009). Mechanism of complex formation between [AuCl4]- and l-methionine. in Polyhedron
Oxford : Pergamon-Elsevier Science Ltd., 28(3), 593-599.
https://doi.org/10.1016/j.poly.2008.11.045

Vujačić AV, Savić J, Sovilj SP, Mészáros SK, Todorović N, Petković M, Vasić VM. Mechanism of complex formation between [AuCl4]- and l-methionine. in Polyhedron. 2009;28(3):593-599.
doi:10.1016/j.poly.2008.11.045 .

Vujačić, Ana V., Savić, J.Z., Sovilj, Sofija P., Mészáros, Szécsényi K., Todorović, Nina, Petković, M.Z., Vasić, Vesna M., "Mechanism of complex formation between [AuCl4]- and l-methionine" in Polyhedron, 28, no. 3 (2009):593-599,
https://doi.org/10.1016/j.poly.2008.11.045 . .