TY  - JOUR
AU  - Prokopijević, Miloš
AU  - Prodanović, Olivera
AU  - Spasojević, Dragica
AU  - Kovacević, Gordana
AU  - Polović, Natalija
AU  - Radotić, Ksenija
AU  - Prodanović, Radivoje
PY  - 2017
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/1096
AB  - Pectin was modified by oxidation with sodium periodate at molar ratios of 2.5, 5, 10, 15 and 20 mol% and reductive amination with tyramine and sodium cyanoborohydride afterwards. Concentration of tyramine groups within modified pectin ranged from 54.5 to 538 mu mol/g of dry pectin while concentration of ionizable groups ranged from 3.0 to 4.0 mmol/g of dry polymer compared to 1.5 mmol/g before modification due to the introduction of amino group. All tyramine-pectins showed exceptional gelling properties and could form hydrogel both by cross-linking of carboxyl groups with calcium or by cross-linking phenol groups with peroxidase in the presence of hydrogen peroxide. These hydrogels were tested as carriers for soybean hull peroxidase (SHP) immobilization within microbeads formed in an emulsion based enzymatic polymerization reaction. SHP immobilized within tyramine-pectin microbeads had an increased thermal and organic solvent stability compared to the soluble enzyme. Immobilized SHP was more active in acidic pH region and had slightly decreased K (m) value of 2.61 mM compared to the soluble enzyme. After 7 cycles of repeated use in batch reactor for pyrogallol oxidation microbeads, immobilized SHP retained half of the initial activity.
PB  - Springer, New York
T2  - Applied Microbiology and Biotechnology
T1  - Tyramine-modified pectins via periodate oxidation for soybean hull peroxidase induced hydrogel formation and immobilization
EP  - 2290
IS  - 6
SP  - 2281
VL  - 101
DO  - 10.1007/s00253-016-8002-x
ER  - 

@article{
author = "Prokopijević, Miloš and Prodanović, Olivera and Spasojević, Dragica and Kovacević, Gordana and Polović, Natalija and Radotić, Ksenija and Prodanović, Radivoje",
year = "2017",
abstract = "Pectin was modified by oxidation with sodium periodate at molar ratios of 2.5, 5, 10, 15 and 20 mol% and reductive amination with tyramine and sodium cyanoborohydride afterwards. Concentration of tyramine groups within modified pectin ranged from 54.5 to 538 mu mol/g of dry pectin while concentration of ionizable groups ranged from 3.0 to 4.0 mmol/g of dry polymer compared to 1.5 mmol/g before modification due to the introduction of amino group. All tyramine-pectins showed exceptional gelling properties and could form hydrogel both by cross-linking of carboxyl groups with calcium or by cross-linking phenol groups with peroxidase in the presence of hydrogen peroxide. These hydrogels were tested as carriers for soybean hull peroxidase (SHP) immobilization within microbeads formed in an emulsion based enzymatic polymerization reaction. SHP immobilized within tyramine-pectin microbeads had an increased thermal and organic solvent stability compared to the soluble enzyme. Immobilized SHP was more active in acidic pH region and had slightly decreased K (m) value of 2.61 mM compared to the soluble enzyme. After 7 cycles of repeated use in batch reactor for pyrogallol oxidation microbeads, immobilized SHP retained half of the initial activity.",
publisher = "Springer, New York",
journal = "Applied Microbiology and Biotechnology",
title = "Tyramine-modified pectins via periodate oxidation for soybean hull peroxidase induced hydrogel formation and immobilization",
pages = "2290-2281",
number = "6",
volume = "101",
doi = "10.1007/s00253-016-8002-x"
}

Prokopijević, M., Prodanović, O., Spasojević, D., Kovacević, G., Polović, N., Radotić, K.,& Prodanović, R.. (2017). Tyramine-modified pectins via periodate oxidation for soybean hull peroxidase induced hydrogel formation and immobilization. in Applied Microbiology and Biotechnology
Springer, New York., 101(6), 2281-2290.
https://doi.org/10.1007/s00253-016-8002-x

Prokopijević M, Prodanović O, Spasojević D, Kovacević G, Polović N, Radotić K, Prodanović R. Tyramine-modified pectins via periodate oxidation for soybean hull peroxidase induced hydrogel formation and immobilization. in Applied Microbiology and Biotechnology. 2017;101(6):2281-2290.
doi:10.1007/s00253-016-8002-x .

Prokopijević, Miloš, Prodanović, Olivera, Spasojević, Dragica, Kovacević, Gordana, Polović, Natalija, Radotić, Ksenija, Prodanović, Radivoje, "Tyramine-modified pectins via periodate oxidation for soybean hull peroxidase induced hydrogel formation and immobilization" in Applied Microbiology and Biotechnology, 101, no. 6 (2017):2281-2290,
https://doi.org/10.1007/s00253-016-8002-x . .

TY  - JOUR
AU  - Blazic, Marija B
AU  - Kovacević, Gordana
AU  - Prodanović, Olivera
AU  - Ostafe, Raluca
AU  - Gavrovic-Jankulović, Marija D
AU  - Fischer, Rainer
AU  - Prodanović, Radivoje
PY  - 2013
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/705
AB  - Glucose oxidase (GOx) catalyzes the oxidation of glucose to form gluconic acid and hydrogen peroxide, a reaction with important applications in food preservation, the manufacture of cosmetics and pharmaceuticals, and the development of glucose monitoring devices and biofuel cells. We expressed Aspergillus niger wild type GOx and the B11 mutant, which has twice the activity of the wild type enzyme at pH 5.5, as C-terminal fusions with the Saccharomyces cerevisiae Aga2 protein, allowing the fusion proteins to be displayed on the surface of yeast EBY100 cells. After expression, we extracted the proteins from the yeast cell wall and purified them by ion-exchange chromatography and ultrafiltration. This produced a broad 100-140 kDa band by denaturing SDS-PAGE and a high-molecular-weight band by native PAGE corresponding to the activity band revealed by zymography. The wild type and B11 fusion proteins had k(cat) values of 33.3 and 61.3 s(-1) and K-m values for glucose of 33.4 and 27.9 mM, respectively. The pH optimum for both enzymes was 5.0. The kinetic properties of the fusion proteins displayed the same ratio as their native counterparts, confirming that yeast surface display is suitable for the high-throughput directed evolution of GOx using flow cytometry for selection. Aga2-GOx fusion proteins in the yeast cell wall could also be used as immobilized catalysts for the production of gluconic acid.
PB  - Academic Press Inc Elsevier Science, San Diego
T2  - Protein Expression and Purification
T1  - Yeast surface display for the expression, purification and characterization of wild-type and B11 mutant glucose oxidases
EP  - 180
IS  - 2
SP  - 175
VL  - 89
DO  - 10.1016/j.pep.2013.03.014
ER  - 

@article{
author = "Blazic, Marija B and Kovacević, Gordana and Prodanović, Olivera and Ostafe, Raluca and Gavrovic-Jankulović, Marija D and Fischer, Rainer and Prodanović, Radivoje",
year = "2013",
abstract = "Glucose oxidase (GOx) catalyzes the oxidation of glucose to form gluconic acid and hydrogen peroxide, a reaction with important applications in food preservation, the manufacture of cosmetics and pharmaceuticals, and the development of glucose monitoring devices and biofuel cells. We expressed Aspergillus niger wild type GOx and the B11 mutant, which has twice the activity of the wild type enzyme at pH 5.5, as C-terminal fusions with the Saccharomyces cerevisiae Aga2 protein, allowing the fusion proteins to be displayed on the surface of yeast EBY100 cells. After expression, we extracted the proteins from the yeast cell wall and purified them by ion-exchange chromatography and ultrafiltration. This produced a broad 100-140 kDa band by denaturing SDS-PAGE and a high-molecular-weight band by native PAGE corresponding to the activity band revealed by zymography. The wild type and B11 fusion proteins had k(cat) values of 33.3 and 61.3 s(-1) and K-m values for glucose of 33.4 and 27.9 mM, respectively. The pH optimum for both enzymes was 5.0. The kinetic properties of the fusion proteins displayed the same ratio as their native counterparts, confirming that yeast surface display is suitable for the high-throughput directed evolution of GOx using flow cytometry for selection. Aga2-GOx fusion proteins in the yeast cell wall could also be used as immobilized catalysts for the production of gluconic acid.",
publisher = "Academic Press Inc Elsevier Science, San Diego",
journal = "Protein Expression and Purification",
title = "Yeast surface display for the expression, purification and characterization of wild-type and B11 mutant glucose oxidases",
pages = "180-175",
number = "2",
volume = "89",
doi = "10.1016/j.pep.2013.03.014"
}

Blazic, M. B., Kovacević, G., Prodanović, O., Ostafe, R., Gavrovic-Jankulović, M. D., Fischer, R.,& Prodanović, R.. (2013). Yeast surface display for the expression, purification and characterization of wild-type and B11 mutant glucose oxidases. in Protein Expression and Purification
Academic Press Inc Elsevier Science, San Diego., 89(2), 175-180.
https://doi.org/10.1016/j.pep.2013.03.014

Blazic MB, Kovacević G, Prodanović O, Ostafe R, Gavrovic-Jankulović MD, Fischer R, Prodanović R. Yeast surface display for the expression, purification and characterization of wild-type and B11 mutant glucose oxidases. in Protein Expression and Purification. 2013;89(2):175-180.
doi:10.1016/j.pep.2013.03.014 .

Blazic, Marija B, Kovacević, Gordana, Prodanović, Olivera, Ostafe, Raluca, Gavrovic-Jankulović, Marija D, Fischer, Rainer, Prodanović, Radivoje, "Yeast surface display for the expression, purification and characterization of wild-type and B11 mutant glucose oxidases" in Protein Expression and Purification, 89, no. 2 (2013):175-180,
https://doi.org/10.1016/j.pep.2013.03.014 . .