Fabrication and characterization of bovine serum albumin-phycocyanobilin conjugate: effect on antioxidant and ligand-binding properties.

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. © 2024 Society of Chemical Industry.

Ovalbumin interaction with polystyrene and polyethylene terephthalate microplastics alters its structural properties.

Contaminating microplastics can interact with food proteins in the food matrix and during digestion. This study investigated adsorption of chicken egg protein ovalbumin to polystyrene (PS, 110 and 260 µm) and polyethylene terephthalate (PET, 140 µm) MPs in acidic and neutral conditions and alterations in ovalbumin structure. Ovalbumin adsorption affinity depended on MPs size (smaller > larger), type (PS > PET) and pH (pH 3 > pH 7). In bulk solution, MPs does not change ovalbumin secondary structure significantly, but induces loosening (at pH 3) and tightening (at pH 7) of tertiary structure. Formed soft corona exclusively consists of full length non-native ovalbumin, while in hard corona also shorter ovalbumin fragments were found. At pH 7 soft corona ovalbumin has rearranged but still preserved level of ordered secondary structure, resulting in preserved thermostability and proteolytic stability, but decreased ability to form fibrils upon heating. Secondary structure changes in soft corona resemble changes in native ovalbumin induced by heat treatment (80 °C). Ovalbumin is abundantly present in corona around microplastics also in the presence of other egg white proteins. These results imply that microplastics contaminating food may bind and change structure and functional properties of the main egg white protein.

Characterization of Nanoprecipitated PET Nanoplastics by 1H NMR and Impact of Residual Ionic Surfactant on Viability of Human Primary Mononuclear Cells and Hemolysis of Erythrocytes.

Manufactured nanoplastic particles (NPs) are indispensable for in vitro and in vivo testing and a health risk assessment of this emerging environmental contaminant is needed. The high surface area and inherent hydrophobicity of plastic materials makes the production of NPs devoid of any contaminants very challenging. In this study, we produced nanoprecipitated polyethylene terephthalate (PET) NPs (300 nm hydrodynamic diameter) with an overall yield of 0.76%. The presence of the ionic surfactant sodium dodecyl sulfate (SDS) was characterized by 1H NMR, where the relative ratio of NP/surfactant was monitored on the basis of the chemical shifts characteristic of PET and SDS. For a wide range of surfactant/NP ratios (17:100 to 1.2:100), the measured zeta potential changed from -42.10 to -34.93 mV, but with an NP concentration up to 100 µg/mL, no clear differences were observed in the cellular assays performed in protein-rich media on primary human cells. The remaining impurities contributed to the outcome of the biological assays applied in protein-free buffers, such as human red blood cell hemolysis. The presence of SDS increased the NP-induced hemolysis by 1.5% in protein-rich buffer and by 7.5% in protein-free buffer. As the size, shape, zeta potential, and contaminants of NPs may all be relevant parameters for the biological effects of NPs, the relative quantification of impurities exemplified in our work by the application of 1H NMR for PET NPs and the ionic surfactant SDS could be a valuable auxiliary method in the quality control of manufactured NPs.

Ultrasensitive Quantification of Crustacean Tropomyosin by Immuno-PCR.

Tropomyosin is the major and predominant allergen among shellfish. This study developed an ultrasensitive immuno-PCR method for the quantification of crustacean tropomyosin in foods. The method couples sandwich ELISA with the real-time PCR (rtPCR) amplification of marker DNAs. Monoclonal anti-TPM antibody was the capture antibody, polyclonal rabbit anti-shrimp tropomyosin antibody was the detection antibody, while natural shrimp tropomyosin served as the standard. A double-stranded amino-DNA was covalently conjugated to a secondary anti-rabbit antibody and subsequently amplified and quantified via rtPCR. The quantification sensitivity of immuno-PCR was 20-fold higher than analogous ELISA, with LOQ 19.8 pg/mL. The developed immuno-PCR method is highly specific for the detection of crustacean tropomyosin and is highly precise in a broad concentration range. Tropomyosin recovery in the spiked vegetable soup was 87.7-115.6%. Crustacean tropomyosin was also quantified in commercial food products. The reported immuno-PCR assay is the most sensitive method for the quantification of crustacean tropomyosin and is the first immuno-PCR-based assay for the quantification of food allergen and food protein in general. The described method could be easily adapted for the specific and ultrasensitive immuno-PCR-based detection of traces of any food allergen that is currently being quantified with ELISA, which is of critical importance for people with food allergies.

Small polystyrene microplastics interfere with the breakdown of milk proteins during static in vitro simulated human gastric digestion.

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.

Sandwich ELISA for the Quantification of Nucleocapsid Protein of SARS-CoV-2 Based on Polyclonal Antibodies from Two Different Species.

In this study, a cost-effective sandwich ELISA test, based on polyclonal antibodies, for routine quantification SARS-CoV-2 nucleocapsid (N) protein was developed. The recombinant N protein was produced and used for the production of mice and rabbit antisera. Polyclonal N protein-specific antibodies served as capture and detection antibodies. The prototype ELISA has LOD 0.93 ng/mL and LOQ 5.3 ng/mL, with a linear range of 1.52-48.83 ng/mL. N protein heat pretreatment (56 °C, 1 h) decreased, while pretreatment with 1% Triton X-100 increased analytical ELISA sensitivity. The diagnostic specificity of ELISA was 100% (95% CI, 91.19-100.00%) and sensitivity was 52.94% (95% CI, 35.13-70.22%) compared to rtRT-PCR (Ct < 40). Profoundly higher sensitivity was obtained using patient samples mostly containing Wuhan-similar variants (Wuhan, alpha, and delta), 62.50% (95% CI, 40.59 to 81.20%), in comparison to samples mostly containing Wuhan-distant variants (Omicron) 30.00% (6.67-65.25%). The developed product has relatively high diagnostic sensitivity in relation to its analytical sensitivity due to the usage of polyclonal antibodies from two species, providing a wide repertoire of antibodies against multiple N protein epitopes. Moreover, the fast, simple, and inexpensive production of polyclonal antibodies, as the most expensive assay components, would result in affordable antigen tests.

Proteomic Profiling of Major Peanut Allergens and Their Post-Translational Modifications Affected by Roasting.

Post-translational modifications (PTMs) are covalent changes occurring on amino acid side chains of proteins and yet are neglected structural and functional aspects of protein architecture. The objective was to detect differences in PTM profiles that take place after roasting using open PTM search. We conducted a bottom-up proteomic study to investigate the impact of peanut roasting on readily soluble allergens and their PTM profiles. Proteomic PTM profiling of certain modifications was confirmed by Western blotting with a series of PTM-specific antibodies. In addition to inducing protein aggregation and denaturation, roasting may facilitate change in their PTM pattern and relative profiling. We have shown that Ara h 1 is the most modified major allergen in both samples in terms of modification versatility and extent. The most frequent PTM was methionine oxidation, especially in roasted samples. PTMs uniquely found in roasted samples were hydroxylation (Trp), formylation (Arg/Lys), and oxidation or hydroxylation (Asn). Raw and roasted peanut extracts did not differ in the binding of IgE from the serum of peanut-sensitised individuals done by ELISA. This study provides a better understanding of how roasting impacts the PTM profile of major peanut allergens and provides a good foundation for further exploration of PTMs.

Molecular Mechanisms of Possible Action of Phenolic Compounds in COVID-19 Protection and Prevention.

The worldwide outbreak of COVID-19 was caused by a pathogenic virus called Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2). Therapies against SARS-CoV-2 target the virus or human cells or the immune system. However, therapies based on specific antibodies, such as vaccines and monoclonal antibodies, may become inefficient enough when the virus changes its antigenicity due to mutations. Polyphenols are the major class of bioactive compounds in nature, exerting diverse health effects based on their direct antioxidant activity and their effects in the modulation of intracellular signaling. There are currently numerous clinical trials investigating the effects of polyphenols in prophylaxis and the treatment of COVID-19, from symptomatic, via moderate and severe COVID-19 treatment, to anti-fibrotic treatment in discharged COVID-19 patients. Antiviral activities of polyphenols and their impact on immune system modulation could serve as a solid basis for developing polyphenol-based natural approaches for preventing and treating COVID-19.

Role of Resveratrol in Prevention and Control of Cardiovascular Disorders and Cardiovascular Complications Related to COVID-19 Disease: Mode of Action and Approaches Explored to Increase Its Bioavailability.

Resveratrol is a phytoalexin produced by many plants as a defense mechanism against stress-inducing conditions. The richest dietary sources of resveratrol are berries and grapes, their juices and wines. Good bioavailability of resveratrol is not reflected in its high biological activity in vivo because of resveratrol isomerization and its poor solubility in aqueous solutions. Proteins, cyclodextrins and nanomaterials have been explored as innovative delivery vehicles for resveratrol to overcome this limitation. Numerous in vitro and in vivo studies demonstrated beneficial effects of resveratrol in cardiovascular diseases (CVD). Main beneficial effects of resveratrol intake are cardioprotective, anti-hypertensive, vasodilatory, anti-diabetic, and improvement of lipid status. As resveratrol can alleviate the numerous factors associated with CVD, it has potential as a functional supplement to reduce COVID-19 illness severity in patients displaying poor prognosis due to cardio-vascular complications. Resveratrol was shown to mitigate the major pathways involved in the pathogenesis of SARS-CoV-2 including regulation of the renin-angiotensin system and expression of angiotensin-converting enzyme 2, stimulation of immune system and downregulation of pro-inflammatory cytokine release. Therefore, several studies already have anticipated potential implementation of resveratrol in COVID-19 treatment. Regular intake of a resveratrol rich diet, or resveratrol-based complementary medicaments, may contribute to a healthier cardio-vascular system, prevention and control of CVD, including COVID-19 disease related complications of CVD.

Expression, purification and immunological characterization of recombinant nucleocapsid protein fragment from SARS-CoV-2.

Serological testing is important method for diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Nucleocapsid (N) protein is the most abundant virus derived protein and strong immunogen. We aimed to find its efficient, low-cost production. SARS-CoV-2 recombinant fragment of nucleocapsid protein (rfNP; 58-419 aa) was expressed in E. coli in soluble form, purified and characterized biochemically and immunologically. Purified rfNP has secondary structure of full-length recombinant N protein, with high percentage of disordered structure (34.2%) and of ß-sheet (40.7%). rfNP was tested in immunoblot using sera of COVID-19 convalescent patients. ELISA was optimized with sera of RT-PCR confirmed positive symptomatic patients and healthy individuals. IgG detection sensitivity was 96% (47/50) and specificity 97% (67/68), while IgM detection was slightly lower (94% and 96.5%, respectively). Cost-effective approach for soluble recombinant N protein fragment production was developed, with reliable IgG and IgM antibodies detection of SARS-CoV-2 infection.

The interactions of the ruthenium(II)-cymene complexes with lysozyme and cytochrome c.

The reactions of four cymene-capped ruthenium(II) compounds with pro-apoptotic protein, cytochrome c (Cyt), and anti-proliferative protein lysozyme (Ly) in carbonate buffer were investigated by ESI-MS, UV-vis absorption, and CD spectroscopy. The complexes with two chloride ligands (C2 and C3) were more reactive toward proteins than those with only one (C1 and C4), and the complex with S,N-chelating ligand (C4) was less reactive than one with O,N-chelating ligand (C1). Dehalogenated complexes are most likely species, initially coordinating proteins for all tested complexes. During the time, protein adducts vividly exchanged non-arene organic ligand L with CO32- and OH-, while cymene moiety was retained. In water, only dehalogenated adducts were identified suggesting that in vivo, in the presence of various anions, dynamic ligand exchange could generate different intermediate protein species. Although all complexes reduced Cyt, the reduction was not dependent on their reactivity to protein, implying that initially noncovalent binding to Cyt occurs, causing its reduction, followed by coordination to protein. Cyt reduction was accompanied with rupture of ferro-Met 80 and occupation of this hem coordination site by a histidine His-33/26. Therefore, in Cyt with C2 and C3, less intensive reduction of hem iron leaves more unoccupied target residues for Ru coordination, leading to more efficient formation of covalent adducts, in comparison to C1 and C4. This study contributes to development of new protein-targeted Ru(II) cymene complexes, and to the design of new cancer therapies based on targeted delivery of Ru(II) arene complexes bound on pro-apoptotic/anti-proliferative proteins as vehicles.

Stabilization of apo α-lactalbumin by binding of epigallocatechin-3-gallate: Experimental and molecular dynamics study.

α-Lactalbumin (ALA) is a Ca2+-binding protein which constitutes up to 20% of whey protein. At acidic pH, and in the apo-state at elevated temperatures, ALA is the classic 'molten globule' (MG). This study examined epigallocatechin-3-gallate (EGCG) binding to ALA in its apo form (apoALA) and stabilizing effect on protein structure thereof. EGCG binds to apoALA in both native and MG state. The complex of EGCG and ALA is more stable to thermal denaturation. The docking analysis and molecular dynamic simulation (MDS) showed that Ca2+ removal decreased conformational stability of ALA, because of the local destabilization of Ca2+-binding region. EGCG binding to apoALA increases its stability by reverting of conformation and stability of Ca2+-binding region. Therefore, EGCG-induced thermal stability of apoALA is based on increased apoALA conformational rigidity. This study implies that during gastric digestion of tea with milk EGCG would remain bound to ALA, albeit in the Ca2+-free form.

Covalent binding of food-derived blue pigment phycocyanobilin to bovine ß-lactoglobulin under physiological conditions.

In this study, we investigated structural aspects of covalent binding of food derived blue pigment phycocyanobilin (PCB) to bovine ß-lactoglobulin (BLG), major whey protein, by spectroscopic, electrophoretic, mass spectrometry and computational methods. At physiological pH (7.2), we found that covalent pigment binding via free cysteine residue is slow (ka = 0.065 min-1), of moderate affinity (Ka = 4 × 104 M-1), and stereo-selective. Binding also occurs at a broad pH range and under simulated gastrointestinal conditions. Adduct formation rises with pH, and in concentrated urea (ka = 0.101 min-1). The BLG-PCB adduct has slightly altered secondary and tertiary protein structure, and bound PCB has higher fluorescence and more stretched conformation than free chromophore. Combination of steered molecular dynamic for disulfide exchange, non-covalent and covalent docking, favours Cys119 residue in protein calyx as target for covalent BLG-PCB adduct formation. Our results suggest that this adduct can serve as delivery system of bioactive PCB.

Glycation of the Major Milk Allergen ß-Lactoglobulin Changes Its Allergenicity by Alterations in Cellular Uptake and Degradation.

SCOPE: During food processing, the Maillard reaction (МR) may occur, resulting in the formation of glycated proteins. Glycated proteins are of particular importance in food allergies because glycation may influence interactions with the immune system. This study compared native and extensively glycated milk allergen ß-lactoglobulin (BLG), in their interactions with cells crucially involved in allergy. METHODS AND RESULTS: BLG was glycated in MR and characterized. Native and glycated BLG were tested in experiments of epithelial transport, uptake and degradation by DCs, T-cell cytokine responses, and basophil cell degranulation using ELISA and flow cytometry. Glycation of BLG induced partial unfolding and reduced its intestinal epithelial transfer over a Caco-2 monolayer. Uptake of glycated BLG by bone marrow-derived dendritic cells (BMDC) was increased, although both BLG forms entered BMDC via the same mechanism, receptor-mediated endocytosis. Once inside the BMDC, glycated BLG was degraded faster, which might have led to observed lower cytokine production in BMDC/CD4+ T-cells coculture. Finally, glycated BLG was less efficient in induction of degranulation of BLG-specific IgE sensitized basophil cells. CONCLUSIONS: This study suggests that glycation of BLG by MR significantly alters its fate in processes involved in immunogenicity and allergenicity, pointing out the importance of food processing in food allergy.

Characterization and effects of binding of food-derived bioactive phycocyanobilin to bovine serum albumin.

Phycocyanobilin (PCB) is a blue tetrapyrrole chromophore of C-phycocyanin, the main protein of the microalga Spirulina, with numerous proven health-related benefits. We examined binding of PCB to bovine serum albumin (BSA) and how it affects protein and ligand stability. Protein fluorescence quenching and microscale thermophoresis demonstrated high-affinity binding (Ka=2×106M-1). Spectroscopic titration with molecular docking analysis revealed two binding sites on BSA, at the inter-domain cleft and at subdomain IB, while CD spectroscopy indicated stereo-selective binding of the P conformer of the pigment to the protein. The PCB protein complex showed increased thermal stability. Although complex formation partly masked the antioxidant properties of PCB and BSA, a mutually protective effect against free radical-induced oxidation was found. BSA could be suitable for delivery of PCB as a food colorant or bioactive component. Our results also highlight subtle differences between PCB binding to bovine vs. human serum albumin.

The Role of Dietary Phenolic Compounds in Protein Digestion and Processing Technologies to Improve Their Antinutritive Properties.

Digestion is the key step for delivering nutrients and bioactive substances to the body. The way different food components interact with each other and with digestive enzymes can modify the digestion process and affect human health. Understanding how food components interact during digestion is essential for the rational design of functional food products. Plant polyphenols have gained much attention for the bioactive roles they play in the human body. However, their strong beneficial effects on human health have also been associated with a negative impact on the digestion process. Due to the generally low absorption of phenolic compounds after food intake, most of the consumed polyphenols remain in the gastrointestinal tract, where they then can exert inhibitory effects on enzymes involved in the degradation of saccharides, lipids, and proteins. While the inhibitory effects of phenolics on the digestion of energy-rich food components (saccharides and lipids) may be regarded as beneficial, primarily in weight-control diets, their inhibitory effects on the digestion of proteins are not desirable for the reason of reduced utilization of amino acids. The effect of polyphenols on protein digestion is reviewed in this article, with an emphasis on food processing methods to improve the antinutritive properties of polyphenols.

Stabilization of Human Serum Albumin by the Binding of Phycocyanobilin, a Bioactive Chromophore of Blue-Green Alga Spirulina: Molecular Dynamics and Experimental Study.

Phycocyanobilin (PCB) binds with high affinity (2.2 x 106 M-1 at 25°C) to human serum albumin (HSA) at sites located in IB and IIA subdomains. The aim of this study was to examine effects of PCB binding on protein conformation and stability. Using 300 ns molecular dynamics (MD) simulations, UV-VIS spectrophotometry, CD, FT-IR, spectrofluorimetry, thermal denaturation and susceptibility to trypsin digestion, we studied the effects of PCB binding on the stability and rigidity of HSA, as well as the conformational changes in PCB itself upon binding to the protein. MD simulation results demonstrated that HSA with PCB bound at any of the two sites showed greater rigidity and lower overall and individual domain flexibility compared to free HSA. Experimental data demonstrated an increase in the α-helical content of the protein and thermal and proteolytic stability upon ligand binding. PCB bound to HSA undergoes a conformational change to a more elongated conformation in the binding pockets of HSA. PCB binding to HSA stabilizes the structure of this flexible transport protein, making it more thermostable and resistant to proteolysis. The results from this work explain at molecular level, conformational changes and stabilization of HSA structure upon ligand binding. The resultant increased thermal and proteolytic stability of HSA may provide greater longevity to HSA in plasma.

Conformational stability of digestion-resistant peptides of peanut conglutins reveals the molecular basis of their allergenicity.

Conglutins represent the major peanut allergens and are renowned for their resistance to gastro-intestinal digestion. Our aim was to characterize the digestion-resistant peptides (DRPs) of conglutins by biochemical and biophysical methods followed by a molecular dynamics simulation in order to better understand the molecular basis of food protein allergenicity. We have mapped proteolysis sites at the N- and C-termini and at a limited internal segment, while other potential proteolysis sites remained unaffected. Molecular dynamics simulation showed that proteolysis only occurred in the vibrant regions of the proteins. DRPs appeared to be conformationally stable as intact conglutins. Also, the overall secondary structure and IgE-binding potency of DRPs was comparable to that of intact conglutins. The stability of conglutins toward gastro-intestinal digestion, combined with the conformational stability of the resulting DRPs provide conditions for optimal exposure to the intestinal immune system, providing an explanation for the extraordinary allergenicity of peanut conglutins.

Digestion by pepsin releases biologically active chromopeptides from C-phycocyanin, a blue-colored biliprotein of microalga Spirulina.

C-phycocyanin, the major protein of cyanobacteria Spirulina, possesses significant antioxidant, anti-cancer, anti-inflammatory and immunomodulatory effects, ascribed to covalently attached linear tetrapyrrole chromophore phycocyanobilin. There are no literature data about structure and biological activities of released peptides with bound chromophore in C-phycocyanin digest. This study aims to identify chromopeptides obtained after pepsin digestion of C-phycocyanin and to examine their bioactivities. C-phycocyanin is rapidly digested by pepsin in simulated gastric fluid. The structure of released chromopeptides was analyzed by high resolution tandem mass spectrometry and peptides varying in size from 2 to 13 amino acid residues were identified in both subunits of C-phycocyanin. Following separation by HPLC, chromopeptides were analyzed for potential bioactivities. It was shown that all five chromopeptide fractions have significant antioxidant and metal-chelating activities and show cytotoxic effect on human cervical adenocarcinoma and epithelial colonic cancer cell lines. In addition, chromopeptides protect human erythrocytes from free radical-induced hemolysis in antioxidative capacity-dependant manner. There was a positive correlation between antioxidative potency and other biological activities of chromopeptides. Digestion by pepsin releases biologically active chromopeptides from C-phycocyanin whose activity is mostly related to the antioxidative potency provided by chromophore.

Complexes of green tea polyphenol, epigalocatechin-3-gallate, and 2S albumins of peanut.

2S albumins of peanuts are seed storage proteins, highly homologous in structure and described as major elicitors of anaphylactic reactions to peanut (allergens Ara h 2 and Ara h 6). Epigallocatechin-3-gallate (EGCG) is the most biologically potent polyphenol of green tea. Non-covalent interactions of EGCG with proteins contribute to its diverse biological activities. Here we used the methods of circular dichroism, fluorescence quenching titration, isothermal titration calorimetry and computational chemistry to elucidate interactions of EGCG and 2S albumins. Similarity in structure and overall fold of 2S albumins yielded similar putative binding sites and similar binding modes with EGCG. Binding affinity determined for Ara h 2 was in the range described for complexes of EGCG and other dietary proteins. Binding of EGCG to 2S albumins affects protein conformation, by causing an α-helix to ß-structures transition in both proteins. 2S albumins of peanuts may be good carriers of physiologically active green tea catechin.