TY  - JOUR
AU  - Radomirović, Mirjana
AU  - Gligorijević, Nikola
AU  - Stanić-Vučinić, Dragana
AU  - Nikolić, Milan
AU  - Ćirković-Veličković, Tanja
PY  - 2024
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/7645
AB  - BACKGROUND: Phycocyanobilin (PCB) is an open-chain blue tetrapyrrole chromophore of C-phycocyanin (C-PC), a major chromoprotein
derived from the cyanobacterium Arthrospira platensis having numerous health-promoting effects. Relying on the
ability of PCB to attach to the sulfhydryl group of proteins, we propose a new method for covalent attachment of PCB to bovine
serum albumin (BSA) as a means of its functionalization.
RESULTS: Traut's reagent (TR, 2-iminothiolane), modifying lysine residues, was used to optimize the introduction of sulfhydryl
groups in BSA. A higher degree of BSA thiolation by TR induces more profound alterations of its structure, resulting in minor
oligomerization and aggregation. A 50-fold molar excess of TR was found to be the optimal, balancing thiolation level and
adverse effect on protein structure. PCB was covalently attached to newly introduced sulfhydryl groups at pH 9 at 20-fold
PCB/BSA ratio. An increase in the TR/BSA molar ratio leads to increased efficiency of PCB conjugation with thiolated BSA. Compared
to native BSA, BSA–PCB conjugate binds quercetin with similar affinity but has higher antioxidant activity and increased
oxidative stability.
CONCLUSIONS: PCB-modified BSA could serve as a stable, food-compatible carrier of bioactive PCB, but also bind other ligands
that would be protected from oxidative damage due to the high antioxidant potential of covalently bound PCB. Thiolation by
TR is, at the same time, a simple method for the covalent functionalization of virtually any protein by bioactive PCB or for
obtaining PCB-based fluorescent probes.
PB  - Wiley
T2  - Journal of the Science of Food and Agriculture
T1  - Fabrication and characterization of bovine serum albumin–phycocyanobilin conjugate: effect on antioxidant and ligand-binding properties
DO  - 10.1002/jsfa.13649
ER  - 

@article{
author = "Radomirović, Mirjana and Gligorijević, Nikola and Stanić-Vučinić, Dragana and Nikolić, Milan and Ćirković-Veličković, Tanja",
year = "2024",
abstract = "BACKGROUND: Phycocyanobilin (PCB) is an open-chain blue tetrapyrrole chromophore of C-phycocyanin (C-PC), a major chromoprotein
derived from the cyanobacterium Arthrospira platensis having numerous health-promoting effects. Relying on the
ability of PCB to attach to the sulfhydryl group of proteins, we propose a new method for covalent attachment of PCB to bovine
serum albumin (BSA) as a means of its functionalization.
RESULTS: Traut's reagent (TR, 2-iminothiolane), modifying lysine residues, was used to optimize the introduction of sulfhydryl
groups in BSA. A higher degree of BSA thiolation by TR induces more profound alterations of its structure, resulting in minor
oligomerization and aggregation. A 50-fold molar excess of TR was found to be the optimal, balancing thiolation level and
adverse effect on protein structure. PCB was covalently attached to newly introduced sulfhydryl groups at pH 9 at 20-fold
PCB/BSA ratio. An increase in the TR/BSA molar ratio leads to increased efficiency of PCB conjugation with thiolated BSA. Compared
to native BSA, BSA–PCB conjugate binds quercetin with similar affinity but has higher antioxidant activity and increased
oxidative stability.
CONCLUSIONS: PCB-modified BSA could serve as a stable, food-compatible carrier of bioactive PCB, but also bind other ligands
that would be protected from oxidative damage due to the high antioxidant potential of covalently bound PCB. Thiolation by
TR is, at the same time, a simple method for the covalent functionalization of virtually any protein by bioactive PCB or for
obtaining PCB-based fluorescent probes.",
publisher = "Wiley",
journal = "Journal of the Science of Food and Agriculture",
title = "Fabrication and characterization of bovine serum albumin–phycocyanobilin conjugate: effect on antioxidant and ligand-binding properties",
doi = "10.1002/jsfa.13649"
}

Radomirović, M., Gligorijević, N., Stanić-Vučinić, D., Nikolić, M.,& Ćirković-Veličković, T.. (2024). Fabrication and characterization of bovine serum albumin–phycocyanobilin conjugate: effect on antioxidant and ligand-binding properties. in Journal of the Science of Food and Agriculture
Wiley..
https://doi.org/10.1002/jsfa.13649

Radomirović M, Gligorijević N, Stanić-Vučinić D, Nikolić M, Ćirković-Veličković T. Fabrication and characterization of bovine serum albumin–phycocyanobilin conjugate: effect on antioxidant and ligand-binding properties. in Journal of the Science of Food and Agriculture. 2024;.
doi:10.1002/jsfa.13649 .

Radomirović, Mirjana, Gligorijević, Nikola, Stanić-Vučinić, Dragana, Nikolić, Milan, Ćirković-Veličković, Tanja, "Fabrication and characterization of bovine serum albumin–phycocyanobilin conjugate: effect on antioxidant and ligand-binding properties" in Journal of the Science of Food and Agriculture (2024),
https://doi.org/10.1002/jsfa.13649 . .

TY  - JOUR
AU  - de Guzman, Maria Krishna
AU  - Stanić-Vučinić, Dragana
AU  - Gligorijević, Nikola
AU  - Wimmer, Lukas
AU  - Gasparyan, Manvel
AU  - Lujić, Tamara
AU  - Vasović, Tamara
AU  - Dailey, Lea Ann
AU  - Van Haute, Sam
AU  - Ćirković-Veličković, Tanja
PY  - 2023
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/6466
AB  - Human ingestion of microplastics (MPs) is common and inevitable due to the widespread contamination of food items, but implications on the gastric digestion of food proteins are still unknown. In this study, the interactions between pepsin and polystyrene (PS) MPs were evaluated by investigating enzyme activity and conformation in a simulated human gastric environment in the presence or absence of PS MPs. The impact on food digestion was also assessed by monitoring the kinetics of protein hydrolysis through static in vitro gastric digestion of cow's milk contaminated with PS. The binding of pepsin to PS showed that the surface chemistry of MPs dictates binding affinity. The key contributor to pepsin adsorption seems to be π−π interactions between the aromatic residues and the PS phenyl rings. During quick exposure (10 min) of pepsin to increasing concentrations (222, 2219, 22188 particles/mL) of 10 μm PS (PS10) and 100 μm PS (PS100), total enzymatic activities were not affected remarkably. However, upon prolonged exposure at 1 and 2 h, preferential binding of pepsin to the small, low zeta-potential PS caused structural changes in the protein which led to a significant reduction of its activity. Digestion of cow's milk mixed with PS10 resulted in transient accumulation of larger peptides (10–35 kDa) and reduced bioavailability of short peptides (2–9 kDa) in the gastric phase. This, however, was only observed at extremely high PS10 concentration (0.3 mg/mL or 5.46E+05 particles/mL). The digestion of milk peptides, bound preferentially over pepsin within the hard corona on the PS10 surface, was delayed up to 15 min in comparison to bulk protein digestion. Intact caseins, otherwise rapidly digested, remained bound to PS10 in the hard corona for up to 15 min. This work presents valuable insights regarding the interaction of MPs, food proteins, and pepsin, and their dynamics during gastric digestion.
PB  - Elsevier Ltd.
T2  - Environmental Pollution
T1  - Small polystyrene microplastics interfere with the breakdown of milk proteins during static in vitro simulated human gastric digestion
VL  - 335
SP  - 122282
DO  - 10.1016/j.envpol.2023.122282
ER  - 

@article{
author = "de Guzman, Maria Krishna and Stanić-Vučinić, Dragana and Gligorijević, Nikola and Wimmer, Lukas and Gasparyan, Manvel and Lujić, Tamara and Vasović, Tamara and Dailey, Lea Ann and Van Haute, Sam and Ćirković-Veličković, Tanja",
year = "2023",
abstract = "Human ingestion of microplastics (MPs) is common and inevitable due to the widespread contamination of food items, but implications on the gastric digestion of food proteins are still unknown. In this study, the interactions between pepsin and polystyrene (PS) MPs were evaluated by investigating enzyme activity and conformation in a simulated human gastric environment in the presence or absence of PS MPs. The impact on food digestion was also assessed by monitoring the kinetics of protein hydrolysis through static in vitro gastric digestion of cow's milk contaminated with PS. The binding of pepsin to PS showed that the surface chemistry of MPs dictates binding affinity. The key contributor to pepsin adsorption seems to be π−π interactions between the aromatic residues and the PS phenyl rings. During quick exposure (10 min) of pepsin to increasing concentrations (222, 2219, 22188 particles/mL) of 10 μm PS (PS10) and 100 μm PS (PS100), total enzymatic activities were not affected remarkably. However, upon prolonged exposure at 1 and 2 h, preferential binding of pepsin to the small, low zeta-potential PS caused structural changes in the protein which led to a significant reduction of its activity. Digestion of cow's milk mixed with PS10 resulted in transient accumulation of larger peptides (10–35 kDa) and reduced bioavailability of short peptides (2–9 kDa) in the gastric phase. This, however, was only observed at extremely high PS10 concentration (0.3 mg/mL or 5.46E+05 particles/mL). The digestion of milk peptides, bound preferentially over pepsin within the hard corona on the PS10 surface, was delayed up to 15 min in comparison to bulk protein digestion. Intact caseins, otherwise rapidly digested, remained bound to PS10 in the hard corona for up to 15 min. This work presents valuable insights regarding the interaction of MPs, food proteins, and pepsin, and their dynamics during gastric digestion.",
publisher = "Elsevier Ltd.",
journal = "Environmental Pollution",
title = "Small polystyrene microplastics interfere with the breakdown of milk proteins during static in vitro simulated human gastric digestion",
volume = "335",
pages = "122282",
doi = "10.1016/j.envpol.2023.122282"
}

de Guzman, M. K., Stanić-Vučinić, D., Gligorijević, N., Wimmer, L., Gasparyan, M., Lujić, T., Vasović, T., Dailey, L. A., Van Haute, S.,& Ćirković-Veličković, T.. (2023). Small polystyrene microplastics interfere with the breakdown of milk proteins during static in vitro simulated human gastric digestion. in Environmental Pollution
Elsevier Ltd.., 335, 122282.
https://doi.org/10.1016/j.envpol.2023.122282

de Guzman MK, Stanić-Vučinić D, Gligorijević N, Wimmer L, Gasparyan M, Lujić T, Vasović T, Dailey LA, Van Haute S, Ćirković-Veličković T. Small polystyrene microplastics interfere with the breakdown of milk proteins during static in vitro simulated human gastric digestion. in Environmental Pollution. 2023;335:122282.
doi:10.1016/j.envpol.2023.122282 .

de Guzman, Maria Krishna, Stanić-Vučinić, Dragana, Gligorijević, Nikola, Wimmer, Lukas, Gasparyan, Manvel, Lujić, Tamara, Vasović, Tamara, Dailey, Lea Ann, Van Haute, Sam, Ćirković-Veličković, Tanja, "Small polystyrene microplastics interfere with the breakdown of milk proteins during static in vitro simulated human gastric digestion" in Environmental Pollution, 335 (2023):122282,
https://doi.org/10.1016/j.envpol.2023.122282 . .