TY  - JOUR
AU  - Dimitrijević, Milena S.
AU  - Bogdanović-Pristov, Jelena
AU  - Žižić, Milan
AU  - Stanković, Dalibor M.
AU  - Bajuk-Bogdanović, Danica V.
AU  - Stanić, Marina
AU  - Spasić, Snežana D.
AU  - Hagen, Wilfred
AU  - Spasojević, Ivan
PY  - 2019
UR  - http://cherry.chem.bg.ac.rs/handle/123456789/3066
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/8200
AB  - Biliverdin (BV), a product of heme catabolism, is known to interact with transition metals, but the details of such interactions under physiological conditions are scarce. Herein, we examined coordinate/redox interactions of BV with Cu2+ in phosphate buffer at pH 7.4, using spectrophotometry, HESI-MS, Raman spectroscopy, 1 H NMR, EPR, fluorimetry, and electrochemical methods. BV formed a stable coordination complex with copper in 1 : 1 stoichiometry. The structure of BV was more planar and energetically stable in the complex. The complex showed strong paramagnetic effects that were attributed to an unpaired delocalized e−. The delocalized electron may come from BV or Cu2+, so the complex is formally composed either of BV radical cation and Cu1+ or of BV radical anion and Cu3+. The complex underwent oxidation only in the presence of both O2 and an excess of Cu2+, or a strong oxidizing agent, and it was resistant to reducing agents. The biological effects of the stable BV metallocomplex containing a delocalized unpaired electron should be further examined, and may provide an answer to the long-standing question of high energy investment in the catabolism of BV, which represents a relatively harmless molecule per se.
T2  - Dalton Transactions
T1  - Biliverdin-copper complex at physiological pH
VL  - 48
IS  - 18
SP  - 6061
EP  - 6070
DO  - 10.1039/c8dt04724c
ER  - 

@article{
author = "Dimitrijević, Milena S. and Bogdanović-Pristov, Jelena and Žižić, Milan and Stanković, Dalibor M. and Bajuk-Bogdanović, Danica V. and Stanić, Marina and Spasić, Snežana D. and Hagen, Wilfred and Spasojević, Ivan",
year = "2019",
abstract = "Biliverdin (BV), a product of heme catabolism, is known to interact with transition metals, but the details of such interactions under physiological conditions are scarce. Herein, we examined coordinate/redox interactions of BV with Cu2+ in phosphate buffer at pH 7.4, using spectrophotometry, HESI-MS, Raman spectroscopy, 1 H NMR, EPR, fluorimetry, and electrochemical methods. BV formed a stable coordination complex with copper in 1 : 1 stoichiometry. The structure of BV was more planar and energetically stable in the complex. The complex showed strong paramagnetic effects that were attributed to an unpaired delocalized e−. The delocalized electron may come from BV or Cu2+, so the complex is formally composed either of BV radical cation and Cu1+ or of BV radical anion and Cu3+. The complex underwent oxidation only in the presence of both O2 and an excess of Cu2+, or a strong oxidizing agent, and it was resistant to reducing agents. The biological effects of the stable BV metallocomplex containing a delocalized unpaired electron should be further examined, and may provide an answer to the long-standing question of high energy investment in the catabolism of BV, which represents a relatively harmless molecule per se.",
journal = "Dalton Transactions",
title = "Biliverdin-copper complex at physiological pH",
volume = "48",
number = "18",
pages = "6061-6070",
doi = "10.1039/c8dt04724c"
}

Dimitrijević, M. S., Bogdanović-Pristov, J., Žižić, M., Stanković, D. M., Bajuk-Bogdanović, D. V., Stanić, M., Spasić, S. D., Hagen, W.,& Spasojević, I.. (2019). Biliverdin-copper complex at physiological pH. in Dalton Transactions, 48(18), 6061-6070.
https://doi.org/10.1039/c8dt04724c

Dimitrijević MS, Bogdanović-Pristov J, Žižić M, Stanković DM, Bajuk-Bogdanović DV, Stanić M, Spasić SD, Hagen W, Spasojević I. Biliverdin-copper complex at physiological pH. in Dalton Transactions. 2019;48(18):6061-6070.
doi:10.1039/c8dt04724c .

Dimitrijević, Milena S., Bogdanović-Pristov, Jelena, Žižić, Milan, Stanković, Dalibor M., Bajuk-Bogdanović, Danica V., Stanić, Marina, Spasić, Snežana D., Hagen, Wilfred, Spasojević, Ivan, "Biliverdin-copper complex at physiological pH" in Dalton Transactions, 48, no. 18 (2019):6061-6070,
https://doi.org/10.1039/c8dt04724c . .

TY  - JOUR
AU  - Dimitrijević, Milena S.
AU  - Bogdanović-Pristov, Jelena
AU  - Žižić, Milan
AU  - Stanković, Dalibor M.
AU  - Bajuk-Bogdanović, Danica V.
AU  - Stanić, Marina
AU  - Spasić, Snežana D.
AU  - Hagen, Wilfred
AU  - Spasojević, Ivan
PY  - 2019
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/8258
AB  - Biliverdin (BV), a product of heme catabolism, is known to interact with transition metals, but the details of such interactions under physiological conditions are scarce. Herein, we examined coordinate/redox interactions of BV with Cu2+ in phosphate buffer at pH 7.4, using spectrophotometry, HESI-MS, Raman spectroscopy, 1 H NMR, EPR, fluorimetry, and electrochemical methods. BV formed a stable coordination complex with copper in 1 : 1 stoichiometry. The structure of BV was more planar and energetically stable in the complex. The complex showed strong paramagnetic effects that were attributed to an unpaired delocalized e−. The delocalized electron may come from BV or Cu2+, so the complex is formally composed either of BV radical cation and Cu1+ or of BV radical anion and Cu3+. The complex underwent oxidation only in the presence of both O2 and an excess of Cu2+, or a strong oxidizing agent, and it was resistant to reducing agents. The biological effects of the stable BV metallocomplex containing a delocalized unpaired electron should be further examined, and may provide an answer to the long-standing question of high energy investment in the catabolism of BV, which represents a relatively harmless molecule per se.
T2  - Dalton Transactions
T1  - Biliverdin-copper complex at physiological pH
VL  - 48
IS  - 18
SP  - 6061
EP  - 6070
DO  - 10.1039/c8dt04724c
ER  - 

@article{
author = "Dimitrijević, Milena S. and Bogdanović-Pristov, Jelena and Žižić, Milan and Stanković, Dalibor M. and Bajuk-Bogdanović, Danica V. and Stanić, Marina and Spasić, Snežana D. and Hagen, Wilfred and Spasojević, Ivan",
year = "2019",
abstract = "Biliverdin (BV), a product of heme catabolism, is known to interact with transition metals, but the details of such interactions under physiological conditions are scarce. Herein, we examined coordinate/redox interactions of BV with Cu2+ in phosphate buffer at pH 7.4, using spectrophotometry, HESI-MS, Raman spectroscopy, 1 H NMR, EPR, fluorimetry, and electrochemical methods. BV formed a stable coordination complex with copper in 1 : 1 stoichiometry. The structure of BV was more planar and energetically stable in the complex. The complex showed strong paramagnetic effects that were attributed to an unpaired delocalized e−. The delocalized electron may come from BV or Cu2+, so the complex is formally composed either of BV radical cation and Cu1+ or of BV radical anion and Cu3+. The complex underwent oxidation only in the presence of both O2 and an excess of Cu2+, or a strong oxidizing agent, and it was resistant to reducing agents. The biological effects of the stable BV metallocomplex containing a delocalized unpaired electron should be further examined, and may provide an answer to the long-standing question of high energy investment in the catabolism of BV, which represents a relatively harmless molecule per se.",
journal = "Dalton Transactions",
title = "Biliverdin-copper complex at physiological pH",
volume = "48",
number = "18",
pages = "6061-6070",
doi = "10.1039/c8dt04724c"
}

Dimitrijević, M. S., Bogdanović-Pristov, J., Žižić, M., Stanković, D. M., Bajuk-Bogdanović, D. V., Stanić, M., Spasić, S. D., Hagen, W.,& Spasojević, I.. (2019). Biliverdin-copper complex at physiological pH. in Dalton Transactions, 48(18), 6061-6070.
https://doi.org/10.1039/c8dt04724c

Dimitrijević MS, Bogdanović-Pristov J, Žižić M, Stanković DM, Bajuk-Bogdanović DV, Stanić M, Spasić SD, Hagen W, Spasojević I. Biliverdin-copper complex at physiological pH. in Dalton Transactions. 2019;48(18):6061-6070.
doi:10.1039/c8dt04724c .

Dimitrijević, Milena S., Bogdanović-Pristov, Jelena, Žižić, Milan, Stanković, Dalibor M., Bajuk-Bogdanović, Danica V., Stanić, Marina, Spasić, Snežana D., Hagen, Wilfred, Spasojević, Ivan, "Biliverdin-copper complex at physiological pH" in Dalton Transactions, 48, no. 18 (2019):6061-6070,
https://doi.org/10.1039/c8dt04724c . .

TY  - JOUR
AU  - Potkonjak, Nebojša I.
AU  - Veselinović, Dragan S.
AU  - Novaković, Miroslav M.
AU  - Gorjanovic, Stanislava Z.
AU  - Pezo, Lato
AU  - Sužnjevicć, Desanka Ž.
PY  - 2012
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/5101
AB  - Antioxidant activity (AO) of commercial propolis extracts (PEs), available on Serbian market, was determined by direct current (DC) polarography. Polarographic anodic current of 5.0 mmol L-1 alkaline solution of H2O2 was recorded at potentials of mercury dissolution. Decrease of the current was plotted against the volume of gradually added PEs. The volume of PE causing 20% current decrease was determined from the linear part of the plot. Antioxidant activity was expressed in H2O2 equivalent (HPEq), representing the volume of PE that corresponds to 1.0 mmol L-1 H2O2 decrease. Resulting HPEq ranged between 1.71 +/- 0.11 and 8.00 +/- 0.18 mu L. Range of 1,1-dipheny1-2-picryl hydrazyl (DPPH) radical scavenging activity was from 0.093 +/- 0.004% to 0.346 +/- 0.006%. Total phenolic content (TCP) of PE with superior AO activity was 5.31 +/- 0.05%g GAE, while the extract with the lowest activity contained 1.45 +/- 0.02%g GAE. Antioxidant activity, determined by polarographic method, was correlated with DPPH scavenging activity (R-2 = 0.991) and TCP (R-2 = 0.985). Validity of obtained results was further confirmed using ANOVA and post hoc Tukey HSD test. (C) 2012 Elsevier Ltd. All rights reserved.
T2  - Food and Chemical Toxicology
T1  - Antioxidant activity of propolis extracts from Serbia: A polarographic approach
VL  - 50
IS  - 10
SP  - 3614
EP  - 3618
DO  - 10.1016/j.fct.2012.07.029
ER  - 

@article{
author = "Potkonjak, Nebojša I. and Veselinović, Dragan S. and Novaković, Miroslav M. and Gorjanovic, Stanislava Z. and Pezo, Lato and Sužnjevicć, Desanka Ž.",
year = "2012",
abstract = "Antioxidant activity (AO) of commercial propolis extracts (PEs), available on Serbian market, was determined by direct current (DC) polarography. Polarographic anodic current of 5.0 mmol L-1 alkaline solution of H2O2 was recorded at potentials of mercury dissolution. Decrease of the current was plotted against the volume of gradually added PEs. The volume of PE causing 20% current decrease was determined from the linear part of the plot. Antioxidant activity was expressed in H2O2 equivalent (HPEq), representing the volume of PE that corresponds to 1.0 mmol L-1 H2O2 decrease. Resulting HPEq ranged between 1.71 +/- 0.11 and 8.00 +/- 0.18 mu L. Range of 1,1-dipheny1-2-picryl hydrazyl (DPPH) radical scavenging activity was from 0.093 +/- 0.004% to 0.346 +/- 0.006%. Total phenolic content (TCP) of PE with superior AO activity was 5.31 +/- 0.05%g GAE, while the extract with the lowest activity contained 1.45 +/- 0.02%g GAE. Antioxidant activity, determined by polarographic method, was correlated with DPPH scavenging activity (R-2 = 0.991) and TCP (R-2 = 0.985). Validity of obtained results was further confirmed using ANOVA and post hoc Tukey HSD test. (C) 2012 Elsevier Ltd. All rights reserved.",
journal = "Food and Chemical Toxicology",
title = "Antioxidant activity of propolis extracts from Serbia: A polarographic approach",
volume = "50",
number = "10",
pages = "3614-3618",
doi = "10.1016/j.fct.2012.07.029"
}

Potkonjak, N. I., Veselinović, D. S., Novaković, M. M., Gorjanovic, S. Z., Pezo, L.,& Sužnjevicć, D. Ž.. (2012). Antioxidant activity of propolis extracts from Serbia: A polarographic approach. in Food and Chemical Toxicology, 50(10), 3614-3618.
https://doi.org/10.1016/j.fct.2012.07.029

Potkonjak NI, Veselinović DS, Novaković MM, Gorjanovic SZ, Pezo L, Sužnjevicć DŽ. Antioxidant activity of propolis extracts from Serbia: A polarographic approach. in Food and Chemical Toxicology. 2012;50(10):3614-3618.
doi:10.1016/j.fct.2012.07.029 .

Potkonjak, Nebojša I., Veselinović, Dragan S., Novaković, Miroslav M., Gorjanovic, Stanislava Z., Pezo, Lato, Sužnjevicć, Desanka Ž., "Antioxidant activity of propolis extracts from Serbia: A polarographic approach" in Food and Chemical Toxicology, 50, no. 10 (2012):3614-3618,
https://doi.org/10.1016/j.fct.2012.07.029 . .