RESUMEN
The elucidation of the interaction mechanism between phospholipids and milk proteins within emulsions is pivotal for comprehending the properties of infant formula fat globules. In this study, multispectral methods and molecular docking were employed to explore the relationship between phosphatidylcholine (PC) and whey protein isolate (WPI). Observations indicate that the binding constant, alongside thermodynamic parameters, diminishes as temperature ascends, hinting at a predominantly static quenching mechanism. Predominantly, van der Waals forces and hydrogen bonds constitute the core interactions between WPI and PC. This assertion is further substantiated by Fourier transform infrared spectroscopy, which verifies PC's influence on WPI's secondary structure. A detailed assessment of thermodynamic parameters coupled with molecular docking reveals that PC predominantly adheres to specific sites within α-lactalbumin, ß-lactoglobulin, and bovine serum albumin, propelled by a synergy of hydrophobic interactions, hydrogen bonding, and van der Waals forces, with binding energies noted at -5.59, -6.71, and -7.85 kcal/mol, respectively. An increment in PC concentration is observed to amplify the emulsification properties of WPI whilst concurrently diminishing the zeta potential. This study establishes a theoretical foundation for applying the PC-WPI interaction mechanism in food.
Asunto(s)
Enlace de Hidrógeno , Interacciones Hidrofóbicas e Hidrofílicas , Simulación del Acoplamiento Molecular , Fosfatidilcolinas , Termodinámica , Proteína de Suero de Leche , Proteína de Suero de Leche/química , Fosfatidilcolinas/química , Espectroscopía Infrarroja por Transformada de Fourier/métodos , Lactoglobulinas/química , Lactoglobulinas/metabolismo , Emulsiones/química , Lactalbúmina/química , Lactalbúmina/metabolismo , Albúmina Sérica Bovina/química , Fórmulas Infantiles/químicaRESUMEN
The effects of complexing conditions on the formation of amylose-lipid-protein complexes and relationships between structure and digestion of amylose-lipid and amylose-lipid-protein complexes were poorly understood. The objective of this study was to investigate the effects of complexing time (0, 0.5, 2, 4 and 6 h) and temperature (60, 70, 80, 90 and 100 °C) on the structure and in vitro amylolysis of amylose-lauric acid (AM-LA) and amylose-lauric acid-ß-lactoglobulin (AM-LA-ßLG) complexes, and to understand the relationships between structure and in vitro digestiblity of these complexes. Longer complexing time and higher complexing temperature promoted the formation of greater amounts of the more stable type II crystallites than type I crystallites in both AM-LA and AM-LA-ßLG complexes, which in turn decreased the rate and extent of the complexes digestion to a greater extent. Correlation analyses between parameters for structure and digestion kinetics showed that both the quantity of AM-LA and AM-LA-ßLG complexes and the quality of their arrangement into V-type crystallites influenced their rate and extent of digestion. This study demonstrates that AM-LA and AM-LA-ßLG complexes can be prepared with designed structural and functional properties tailored for various applications.
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Amilosa , Lactoglobulinas , Amilosa/química , Lactoglobulinas/química , Lactoglobulinas/metabolismo , Ácidos Láuricos/química , Temperatura , Cinética , Digestión , HidrólisisRESUMEN
Sheep's milk (SM) is known to differ from cow's milk (CM) in nutritional composition and physicochemical properties, which may lead to different digestion behaviours. This work aimed to investigate the impact of the species (cow vs sheep) and the structure (milk vs yogurt) on the digestion of dairy products. Using an in vitro static gastrointestinal digestion model, CM, SM, cow's milk yogurt (CY) and sheep's milk yogurt (SY) were compared on particle size evolution, microscopic observations, degree of lipolysis, degree of proteolysis, specific protein degradation and calcium bioaccessibility. Species and structure affected particle size evolution during the gastric phase resulting in smaller particles for yogurts compared to milks as well as for CM products compared to SM products. Species impacted lipid composition and lipolysis, with SM products presenting higher short/medium-chain fatty acids content and higher intestinal degree of lipolysis. Proteolysis was influenced by structure, with milks showing higher intestinal degree of proteolysis compared to yogurts. Caseins were digested faster in CM, âº-lactalbumin was digested faster in SM despite its higher concentration, and during gastric digestion ß-lactoglobulin was more degraded in CM products compared to SM products and more in yogurts compared to milks. Lastly, SM products released more bioaccessible calcium than CM products. In conclusion, species (cow vs sheep) impacted more the digestion compared to the structure (milk vs yogurt). In fact, SM was different from CM mainly due to a denser protein network that might slow down the accessibility of the enzyme to its substrate which induce a delay of gastric disaggregation and thus lead to slower the digestion of the nutrients.
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Digestión , Lipólisis , Leche , Tamaño de la Partícula , Proteolisis , Yogur , Animales , Digestión/fisiología , Bovinos , Yogur/análisis , Ovinos , Leche/química , Lactoglobulinas/metabolismo , Tracto Gastrointestinal/metabolismo , Productos Lácteos/análisis , Lactalbúmina/metabolismo , Caseínas/metabolismo , Caseínas/análisis , Especificidad de la Especie , Proteínas de la Leche/análisis , Proteínas de la Leche/metabolismoRESUMEN
Numerous studies have highlighted the potential of Lactic acid bacteria (LAB) fermentation of whey proteins for alleviating allergies. Nonetheless, the impact of LAB-derived metabolites on whey proteins antigenicity during fermentation remains uncertain. Our objective was to elucidate the impact of small molecular metabolites on the antigenicity of α-lactalbumin (α-LA) and ß-lactoglobulin (ß-LG). Through metabolomic analysis, we picked 13 bioactive small molecule metabolites from Lactobacillus delbrueckii subsp. bulgaricus DLPU F-36 for coincubation with α-LA and ß-LG, respectively. The outcomes revealed that valine, arginine, benzoic acid, 2-keto butyric acid, and glutaric acid significantly diminished the sensitization potential of α-LA and ß-LG, respectively. Moreover, chromatographic analyses unveiled the varying influence of small molecular metabolites on the structure of α-LA and ß-LG, respectively. Notably, molecular docking underscored that the primary active sites of α-LA and ß-LG involved in protein binding to IgE antibodies aligned with the interaction sites of small molecular metabolites. In essence, LAB-produced metabolites wield a substantial influence on the antigenic properties of whey proteins.
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Lactobacillus delbrueckii , Simulación del Acoplamiento Molecular , Proteína de Suero de Leche , Lactobacillus delbrueckii/metabolismo , Lactobacillus delbrueckii/química , Lactobacillus delbrueckii/inmunología , Proteína de Suero de Leche/química , Proteína de Suero de Leche/metabolismo , Fermentación , Lactoglobulinas/química , Lactoglobulinas/inmunología , Lactoglobulinas/metabolismo , Lactalbúmina/química , Lactalbúmina/inmunología , Lactalbúmina/metabolismo , Animales , Bovinos , Antígenos/inmunología , Antígenos/químicaRESUMEN
The elucidation of protein-membrane interactions is pivotal for comprehending the mechanisms underlying diverse biological phenomena and membrane-related diseases. In this investigation, vacuum-ultraviolet circular dichroism (VUVCD) spectroscopy, utilizing synchrotron radiation (SR), was employed to dynamically observe membrane interaction processes involving water-soluble proteins at the secondary-structure level. The study utilized a time-resolved (TR) T-shaped microfluidic cell, facilitating the rapid and efficient mixing of protein and membrane solutions. This system was instrumental in acquiring measurements of the time-resolved circular dichroism (TRCD) spectra of ß-lactoglobulin (bLG) during its interaction with lysoDMPG micelles. The results indicate that bLG undergoes a ß-α conformation change, leading to the formation of the membrane-interacting state (M-state), with structural alterations occurring in more than two steps. Global fitting analysis, employing biexponential functions with all of the TRCD spectral data sets, yielded two distinct rate constants (0.18 ± 0.01 and 0.06 ± 0.003/s) and revealed a unique spectrum corresponding to an intermediate state (I-state). Secondary-structure analysis of bLG in its native (N-, I-, and M-states) highlighted that structural changes from the N- to I-states predominantly occurred in the N- and C-terminal regions, which were prominently exposed to the membrane. Meanwhile, transitions from the I- to M-states extended into the inner barrel regions of bLG. Further examination of the physical properties of α-helical segments, such as effective charge and hydrophobicity, revealed that the N- to I- and I- to M-state transitions, which are ascribed to first- and second-rate constants, respectively, are primarily driven by electrostatic and hydrophobic interactions, respectively. These findings underscore the capability of the TR-VUVCD system as a robust tool for characterizing protein-membrane interactions at the molecular level.
Asunto(s)
Dicroismo Circular , Lactoglobulinas , Lactoglobulinas/química , Lactoglobulinas/metabolismo , Vacio , Micelas , Estructura Secundaria de Proteína , Animales , Factores de Tiempo , BovinosRESUMEN
A novel strategy combining ferulic acid and glucose was proposed to reduce ß-lactoglobulin (BLG) allergenicity and investigate whether the reduction in allergenicity was associated with gut microbiome and serum metabolism. As a result, the multistructure of BLG changed, and the modified BLG decreased significantly the contents of IgE, IgG, IgG1, and mMCP-1 in serum, improved the diversity and structural composition of gut microbiota, and increased the content of short-chain fatty acids (SCFAs) in allergic mice. Meanwhile, allergic mice induced by BLG affected arachidonic acid, tryptophan, and other metabolic pathways in serum, the modified BLG inhibited the production of metabolites in arachidonic acid metabolism pathway and significantly increased tryptophan metabolites, and this contribution helps in reducing BLG allergenicity. Overall, reduced allergenicity of BLG after ferulic acid was combined with glucose modification by regulating gut microbiota, the metabolic pathways of arachidonic acid and tryptophan. The results may offer new thoughts alleviating the allergy risk of allergenic proteins.
Asunto(s)
Alérgenos , Ácidos Cumáricos , Microbioma Gastrointestinal , Glucosa , Lactoglobulinas , Ácidos Cumáricos/metabolismo , Ácidos Cumáricos/química , Animales , Lactoglobulinas/inmunología , Lactoglobulinas/química , Lactoglobulinas/metabolismo , Ratones , Humanos , Alérgenos/inmunología , Alérgenos/química , Alérgenos/metabolismo , Glucosa/metabolismo , Femenino , Bacterias/inmunología , Bacterias/metabolismo , Bacterias/clasificación , Bacterias/genética , Ratones Endogámicos BALB C , Inmunoglobulina E/inmunología , Inmunoglobulina E/sangre , Ácidos Grasos Volátiles/metabolismo , Bovinos , Inmunoglobulina G/inmunología , Inmunoglobulina G/sangre , Hipersensibilidad a la Leche/inmunologíaRESUMEN
ß-lactoglobulin (BLG) forms amyloid-like aggregates at high temperatures, low pH, and low ionic strengths. At a pH below 2, BLG undergoes hydrolysis into peptides, with N-terminal peptides 1-33 and 1-52 being prone to fibrillization, forming amyloid-like fibrils. Due to their good mechanical properties, BLG amyloids demonstrate great potential for diverse applications, including biosensors, nanocomposites, and catalysts. Consequently, further studies are essential to comprehensively understand the factors governing the formation of BLG amyloid-like morphologies. In this study, all-atom molecular dynamics simulations were employed to explore the aggregation of N-terminal 1-33 and 1-52 BLG peptides under conditions of pH 2 and at 10 mM NaCl concentration. The simulations revealed that the peptides spontaneously assembled into aggregates of varying sizes. The aggregation process was enabled by the low charge of peptides and the presence of hydrophobic residues within them. As the peptides associated into aggregates, there was a concurrent increase in ß-sheet structures and the establishment of hydrogen bonds, enhancing the stability of the aggregates. Notably, on average, 1-33 peptides formed larger aggregates compared to their 1-52 counterparts, while the latter exhibited a slightly higher content of ß-sheets and higher cluster orderliness. The applied approach facilitated insights into the early stages of amyloid-like aggregation and molecular-level insight into the formation of ß-sheets, which serve as nucleation points for further fibril growth.
Asunto(s)
Lactoglobulinas , Simulación de Dinámica Molecular , Agregado de Proteínas , Lactoglobulinas/química , Lactoglobulinas/metabolismo , Interacciones Hidrofóbicas e Hidrofílicas , Enlace de Hidrógeno , Amiloide/química , Péptidos/química , Concentración de Iones de Hidrógeno , Fragmentos de Péptidos/química , Fragmentos de Péptidos/metabolismoRESUMEN
Micro- and nano-plastics (NPs) are found in human milk, blood, tissues, and organs and associate with aberrant health outcomes including inflammation, genotoxicity, developmental disorders, onset of chronic diseases, and autoimmune disorders. Yet, interfacial interactions between plastics and biomolecular systems remain underexplored. Here, we have examined experimentally, in vitro, in vivo, and by computation, the impact of polystyrene (PS) NPs on a host of biomolecular systems and assemblies. Our results reveal that PS NPs essentially abolished the helix-content of the milk protein ß-lactoglobulin (BLG) in a dose-dependent manner. Helix loss is corelated with the near stoichiometric formation of ß-sheet elements in the protein. Structural alterations in BLG are also likely responsible for the nanoparticle-dependent attrition in binding affinity and weaker on-rate constant of retinol, its physiological ligand (compromising its nutritional role). PS NP-driven helix-to-sheet conversion was also observed in the amyloid-forming trajectory of hen egg-white lysozyme (accelerated fibril formation and reduced helical content in fibrils). Caenorhabditis elegans exposed to PS NPs exhibited a decrease in the fluorescence of green fluorescent protein-tagged dopaminergic neurons and locomotory deficits (akin to the neurotoxin paraquat exposure). Finally, in silico analyses revealed that the most favorable PS/BLG docking score and binding energies corresponded to a pose near the hydrophobic ligand binding pocket (calyx) of the protein where the NP fragment was found to make nonpolar contacts with side-chain residues via the hydrophobic effect and van der Waals forces, compromising side chain/retinol contacts. Binding energetics indicate that PS/BLG interactions destabilize the binding of retinol to the protein and can potentially displace retinol from the calyx region of BLG, thereby impairing its biological function. Collectively, the experimental and high-resolution in silico data provide new insights into the mechanism(s) by which PS NPs corrupt the bimolecular structure and function, induce amyloidosis and onset neuronal injury, and drive aberrant physiological and behavioral outcomes.
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Caenorhabditis elegans , Lactoglobulinas , Muramidasa , Animales , Muramidasa/química , Muramidasa/metabolismo , Lactoglobulinas/química , Lactoglobulinas/metabolismo , Caenorhabditis elegans/metabolismo , Poliestirenos/química , Nanopartículas/química , Vitamina A/química , Vitamina A/metabolismo , Humanos , Homeostasis/efectos de los fármacos , Plásticos/químicaRESUMEN
The gut barrier plays an important role in health maintenance by preventing the invasion of dietary pathogens and toxins. Disruption of the gut barrier can cause severe intestinal inflammation. As a natural source, milk is enriched with many active constituents that contribute to numerous beneficial functions, including immune regulation. These components collectively serve as a shield for the gut barrier, protecting against various threats such as biological, chemical, mechanical, and immunological threats. This comprehensive review delves into the active ingredients in milk, encompassing casein, α-lactalbumin, ß-lactoglobulin, lactoferrin, the milk fat globular membrane, lactose, transforming growth factor, and glycopeptides. The primary focus is to elucidate their impact on the integrity and function of the gut barrier. Furthermore, the implications of different processing methods of dairy products on the gut barrier protection are discussed. In conclusion, this study aimed to underscore the vital role of milk and dairy products in sustaining gut barrier health, potentially contributing to broader perspectives in nutritional sciences and public health.
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Caseínas , Leche , Animales , Leche/metabolismo , Caseínas/metabolismo , Lactalbúmina/metabolismo , Lactoglobulinas/metabolismo , DietaRESUMEN
Per- and polyfluoroalkyl substances (PFAS) pose significant health risks due to their widespread presence in various environmental and biological matrices. However, the molecular-level mechanisms underlying the interactions between PFAS and biological constituents, including proteins, carbohydrates, lipids, and DNA, remain poorly understood. Here, we investigate the interactions between a legacy PFAS, viz. perfluorooctanoic acid (PFOA), and the milk protein ß-lactoglobulin (BLG) obtained using a combination of experimental and computational techniques. Circular dichroism studies reveal that PFOA perturbs the secondary structure of BLG, by driving a dose-dependent loss of α-helicity and alterations in its ß-sheet content. Furthermore, exposure of the protein to PFOA attenuates the on-rate constant for the binding of the hydrophobic probe 8-anilino-1-naphthalene sulfonic acid (ANS), suggesting potential functional impairment of BLG by PFOA. Steered molecular dynamics and umbrella sampling calculations reveal that PFOA binding leads to the formation of an energetically favorable novel binding pocket within the protein, when residues 129-142 are steered to unfold from their initial α-helical structure, wherein a host of intermolecular interactions between PFOA and BLG's residues serve to insert the PFOA into the region between the unfolded helix and beta-sheets. Together, the data provide a novel understanding of the atomic and molecular mechanism(s) by which PFAS modulates structure and function in a globular protein, leading to a beginning of our understanding of altered biological outcomes.
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Caprilatos , Fluorocarburos , Lactoglobulinas , Fluorocarburos/química , Caprilatos/química , Lactoglobulinas/química , Lactoglobulinas/metabolismo , Sitios de Unión , Unión Proteica , Simulación de Dinámica Molecular , Conformación Proteica en Hélice alfa , Modelos Moleculares , Dicroismo CircularRESUMEN
ß-lactoglobulin (BLG) is the major whey protein with negative charges at neutral pH in aqueous media. Thus, the interaction with mucins, the major polyanionic component of mucus, is very weak due to the electrostatic repulsion between them. The present study postulates that cationization of BLG molecules may reverse the interaction characteristics between BLG and mucin from repulsive to associative. To this end, cationic-modified BLGs were prepared by grafting positively charged ethylenediamine (EDA) moieties into the negatively charged carboxyl groups on the aspartic and glutamic acid residues and compared with non-modified BLG upon mixing with porcine gastric mucin (PGM). To characterize the structural and conformational features of PGM, non/cationized BLGs, and their mixtures, various spectroscopic approaches, including zeta potential, dynamic light scattering (DLS), and circular dichroism (CD) spectroscopy were employed. Importantly, we have taken surface adsorption with optical waveguide lightmode spectroscopy (OWLS), and tribological properties with pin-on-disk tribometry at the sliding interface as the key approaches to determine the interaction nature between them as mixing PGM with polycations can lead to synergistic lubrication at the nonpolar substrate in neutral aqueous media as a result of an electrostatic association. All the spectroscopic studies and a substantial improvement in lubricity collectively supported a tenacious and associative interaction between PGM and cationized BLGs, but not between PGM and non-modified BLG. This study demonstrates a unique and successful approach to intensify the interaction between BLG and mucins, which is meaningful for a broad range of disciplines, including food science, macromolecular interactions, and biolubrication etc.
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Cationes , Mucinas Gástricas , Lactoglobulinas , Animales , Porcinos , Mucinas Gástricas/química , Mucinas Gástricas/metabolismo , Cationes/química , Lactoglobulinas/química , Lactoglobulinas/metabolismo , Dicroismo Circular , Etilenodiaminas/química , Electricidad Estática , AdsorciónRESUMEN
A recently developed proteolytic reactor, designed for protein structural investigation, was coupled to ion mobility mass spectrometry to monitor collisional cross section (CCS) evolution of model proteins undergoing trypsin-mediated mono enzymatic digestion. As peptides are released during digestion, the CCS of the remaining protein structure may deviate from the classical 2/3 power of the CCS-mass relationship for spherical structures. The classical relationship between CCS and mass (CCS = A × M2/3) for spherical structures, assuming a globular shape in the gas phase, may deviate as stabilizing elements are lost during digestion. In addition, collision-induced unfolding (CIU) experiments on partially digested proteins provided insights into the CCS resilience in the gas phase to ion activation, potentially due to the presence of stabilizing elements. The study initially investigated a model peptide ModBea (3 kDa), assessing the impact of disulfide bridges on CCS resilience in both reduced and oxidized forms. Subsequently, ß-lactoglobulin (2 disulfide bridges), calmodulin (Ca2+ coordination cation), and cytochrome c (heme) were selected to investigate the influence of common structuring elements on CCS resilience. CIU experiments probed the unfolding process, evaluating the effect of losing specific peptides on the energy landscapes of partially digested proteins. Comparisons of the TWCCSN2âHe to trend curves describing the CCS/mass relationship revealed that proteins with structure-stabilizing elements consistently exhibit TWCCSN2âHe and greater resilience toward CIU compared to proteins lacking these elements. The integration of online digestion, ion mobility, and CIU provides a valuable tool for identifying structuring elements in biopolymers in the gas phase.
Asunto(s)
Calmodulina , Espectrometría de Movilidad Iónica , Desplegamiento Proteico , Proteínas , Espectrometría de Movilidad Iónica/métodos , Proteínas/química , Calmodulina/química , Calmodulina/metabolismo , Lactoglobulinas/química , Lactoglobulinas/metabolismo , Citocromos c/química , Citocromos c/análisis , Espectrometría de Masas/métodos , Péptidos/química , Péptidos/análisis , Tripsina/química , Tripsina/metabolismo , Animales , Conformación ProteicaRESUMEN
Per- and polyfluoroalkyl substances (PFAS) are known for their high environmental persistence and potential toxicity. The presence of PFAS has been reported in many dairy products. However, the mechanisms underlying the accumulation of PFAS in these products remain unclear. Here, we used native mass spectrometry and molecular dynamics simulations to probe the interactions between 19 PFAS of environmental concern and two isoforms of the major bovine whey protein ß-lactoglobulin (ß-LG). We observed that six of these PFAS bound to both protein isoforms with low- to mid-micromolar dissociation constants. Based on quantitative, competitive binding experiments with endogenous ligands, PFAS can bind orthosterically and preferentially to ß-LG's hydrophobic ligand-binding calyx. ß-Cyclodextrin can also suppress binding of PFAS to ß-LG owing to the ability of ß-cyclodextrin to directly sequester PFAS from solution. This research sheds light on PFAS-ß-LG binding, suggesting that such interactions could impact lipid-fatty acid transport in bovine mammary glands at high PFAS concentrations. Furthermore, our results highlight the potential use of ß-cyclodextrin in mitigating PFAS binding, providing insights toward the development of strategies to reduce PFAS accumulation in dairy products and other biological systems.
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Fluorocarburos , Lactoglobulinas , Leche , Animales , Lactoglobulinas/metabolismo , Lactoglobulinas/química , Bovinos , Leche/química , Leche/metabolismo , Fluorocarburos/química , Fluorocarburos/metabolismo , Simulación de Dinámica Molecular , beta-Ciclodextrinas/química , beta-Ciclodextrinas/metabolismo , Sitios de Unión , Unión ProteicaRESUMEN
Organophosphorus are typically hazardous chemicals used in the pharmaceutical, agricultural, and other industries. They pose a serious risk to human life and can be fatal upon direct exposure. Hence, studying the interaction between such compounds with proteins is crucial for environmental, health, and food safety. In this study, we investigated the interaction mechanism between azinphos-methyl (AZM) and ß-lactoglobulin (BLG) at pH 7.4 using a combination of biophysical techniques. Intrinsic fluorescence investigations revealed that BLG fluorescence was quenched in the presence of increasing AZM concentrations. The quenching mechanism was identified as static, as evidenced by a decrease in the fluorescence quenching constant (1.25 × 104, 1.18 × 104, and 0.86 × 104 M-1) with an increase in temperatures. Thermodynamic calculations (ΔH > 0; ΔS > 0) affirmed the formation of a complex between AZM and BLG through hydrophobic interactions. The BLG's secondary structure was found to be increased due to AZM interaction. Ultraviolet -visible spectroscopy data showed alterations in BLG conformation in the presence of AZM. Molecular docking highlighted the significant role of hydrophobic interactions involving residues such as Val43, Ile56, Ile71, Val92, Phe105, and Met107 in the binding between BLG and AZM. A docking energy of -6.9 kcal mol-1, and binding affinity of 1.15 × 105 M-1 suggest spontaneous interaction between AZM and BLG with moderate to high affinity. These findings underscore the potential health risks associated with the entry of AZM into the food chain, emphasizing the need for further consideration of its impact on human health.
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Azinfosmetilo , Lactoglobulinas , Simulación del Acoplamiento Molecular , Plaguicidas , Termodinámica , Lactoglobulinas/química , Lactoglobulinas/metabolismo , Bovinos , Animales , Azinfosmetilo/química , Plaguicidas/química , Plaguicidas/metabolismo , Espectrometría de Fluorescencia , Interacciones Hidrofóbicas e Hidrofílicas , Unión Proteica , Estructura Secundaria de ProteínaRESUMEN
Milk samples were collected from 3625 Chinese Holstein cows to assess the effects of κ-casein (κ-CN) and ß-lactoglobulin (ß-LG) genetic variants on its milk coagulation properties. The results show that Chinese Holstein cows have a higher frequency of the κ-CN AA and AB variants, and ß-LG of the AB and AA variants. Of these, κ-CN B variants, the ß-LG AA and BB variants were more frequent in milk showing good coagulation. The effects of the genetic variants on milk composition, milk proteome, and protein phosphorylation sites were studied. The results showed that higher concentrations of protein and dry matter were found in κ-CN BE variant. Moreover, large variations in milk proteome among different κ-CN and ß-LG variants were observed. Highly phosphorylated for κ-CN, especially Ser97, was observed in cows with the κ-CN BE variant, but no effect of ß-LG variants on phosphorylation site was found. Of the various factors examined, variation of κ-CN phosphorylation sites Ser97 may be the most important in affecting casein structure and milk coagulation ability. Some milk protein contents were found to be negative factors for milk coagulation. In summary, this study showed that κ-CN genetic variants contained different milk compositions and phosphorylation site Ser97 influenced milk coagulation.
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Leche , Proteoma , Animales , Femenino , Bovinos , Proteoma/metabolismo , Fosforilación , Leche/química , Proteínas de la Leche/química , Caseínas/química , Lactoglobulinas/genética , Lactoglobulinas/metabolismo , GenotipoRESUMEN
The aim of this study was to assess whether adding Ca2+ to aggregate or native forms of ß-lactoglobulin alters gut hormone secretion, gastric emptying rates and energy intake in healthy men and women. Fifteen healthy adults (mean ± sd: 9M/6F, age: 24 ± 5 years) completed four trials in a randomised, double-blind, crossover design. Participants consumed test drinks consisting of 30 g of ß-lactoglobulin in a native form with (NATIVE + MINERALS) and without (NATIVE) a Ca2+-rich mineral supplement and in an aggregated form both with (AGGREG + MINERALS) and without the mineral supplement (AGGREG). Arterialised blood was sampled for 120 min postprandially to determine gut hormone concentrations. Gastric emptying was determined using 13C-acetate and 13C-octanoate, and energy intake was assessed with an ad libitum meal at 120 min. A protein × mineral interaction effect was observed for total glucagon-like peptide-1 (GLP-1TOTAL) incremental AUC (iAUC; P < 0·01), whereby MINERALS + AGGREG increased GLP-1TOTAL iAUC to a greater extent than AGGREG (1882 ± 603 v. 1550 ± 456 pmol·l-1·120 min, P < 0·01), but MINERALS + NATIVE did not meaningfully alter the GLP-1 iAUC compared with NATIVE (1669 ± 547 v. 1844 ± 550 pmol·l-1·120 min, P = 0·09). A protein × minerals interaction effect was also observed for gastric emptying half-life (P < 0·01) whereby MINERALS + NATIVE increased gastric emptying half-life compared with NATIVE (83 ± 14 v. 71 ± 8 min, P < 0·01), whereas no meaningful differences were observed between MINERALS + AGGREG v. AGGREG (P = 0·70). These did not result in any meaningful changes in energy intake (protein × minerals interaction, P = 0·06). These data suggest that the potential for Ca2+ to stimulate GLP-1 secretion at moderate protein doses may depend on protein form. This study was registered at clinicaltrials.gov (NCT04659902).
Asunto(s)
Calcio de la Dieta , Estudios Cruzados , Ingestión de Energía , Vaciamiento Gástrico , Péptido 1 Similar al Glucagón , Lactoglobulinas , Humanos , Péptido 1 Similar al Glucagón/sangre , Péptido 1 Similar al Glucagón/metabolismo , Masculino , Femenino , Adulto , Método Doble Ciego , Adulto Joven , Lactoglobulinas/metabolismo , Calcio de la Dieta/administración & dosificación , Suplementos Dietéticos , Periodo Posprandial , Calcio/metabolismoRESUMEN
Whey protein derived bioactives, including α-lactalbumin, ß-lactoglobulin, bovine serum albumin, lactoferrin, transferrin, and proteose-peptones, have exhibited wide ranges of functional, biological and therapeutic properties varying from anticancer, antihypertensive, and antimicrobial effects. In addition, their functional properties involve gelling, emulsifying, and foaming abilities. For these reasons, this review article is framed to understand the relationship existed in between those compound levels and structures with their main functional, biological, and therapeutic properties exhibited either in vitro or in vivo. The impacts of hydrolysis mechanism and separation techniques in enhancing those properties are likewise discussed. Furthermore, special emphasize is given to multifunctional effects of whey derived bioactives and their future trends in ameliorating further food, pharmaceutical, and nutraceutical products. The underlying mechanism effects of those properties are still remained unclear in terms of activity levels, efficacy, and targeted effectiveness. For these reasons, some important models linking to functional properties, thermal properties and cell circumstances are established. Moreover, the coexistence of radical trapping groups, chelating groups, sulfhydryl groups, inhibitory groups, and peptide bonds seemed to be the key elements in triggering those functions and properties. Practical Application: Whey proteins are the byproducts of cheese processing and usually the exploitation of these food waste products has increasingly getting acceptance in many countries, especially European countries. Whey proteins share comparable nutritive values to milk products, particularly on their richness on important proteins that can serve immune protection, structural, and energetic roles. The nutritive profile of whey proteins shows diverse type of bioactive molecules like α-lactalbumin, ß-lactoglobulin, lactoferrin, transferrin, immunoglobulin, and proteose peptones with wide biological importance to the living system, such as in maintaining immunological, neuronal, and signaling roles. The diversification of proteins of whey products prompted scientists to exploit the real mechanisms behind of their biological and therapeutic effects, especially in declining the risk of cancer, tumor, and further complications like diabetes type 2 and hypertension risk effects. For these reasons, profiling these types of proteins using different proteomic and peptidomic approaches helps in determining their biological and therapeutic targets along with their release into gastrointestinal tract conditions and their bioavailabilities into portal circulation, tissue, and organs. The wide applicability of those protein fractions and their derivative bioactive products showed significant impacts in the field of emulsion and double emulsion stabilization by playing roles as emulsifying, surfactant, stabilizing, and foaming agents. Their amphoteric properties helped them to act as excellent encapsulating agents, particularly as vehicle for delivering important vitamins and bioactive compounds. The presence of ferric elements increased their transportation to several metal-ions in the same time increased their scavenging effects to metal-transition and peroxidation of lipids. Their richness with almost essential and nonessential amino acids makes them as selective microbial starters, in addition their richness in sulfhydryl amino acids allowed them to act a cross-linker in conjugating further biomolecules. For instance, conjugating gold-nanoparticles and fluorescent materials in targeting diseases like cancer and tumors in vivo is considered the cutting-edges strategies for these versatile molecules due to their active diffusion across-cell membrane and the presence of specific transporters to these therapeutic molecules.
Asunto(s)
Neoplasias , Peptidomiméticos , Eliminación de Residuos , Humanos , Proteína de Suero de Leche/metabolismo , Lactalbúmina/metabolismo , Proteínas de la Leche/química , Proteínas de la Leche/metabolismo , Proteínas de la Leche/farmacología , Lactoferrina/metabolismo , Peptonas/metabolismo , Hidrólisis , Emulsiones , Proteómica , Lactoglobulinas/química , Lactoglobulinas/metabolismo , AminoácidosRESUMEN
The only FDA-approved oral immunotherapy for a food allergy provides protection against accidental exposure to peanuts. However, this therapy often causes discomfort or side effects and requires long-term commitment. Better preventive and therapeutic solutions are urgently needed. We develop a tolerance-inducing vaccine technology that utilizes glycosylation-modified antigens to induce antigen-specific non-responsiveness. The glycosylation-modified antigens are administered intravenously (i.v.) or subcutaneously (s.c.) and traffic to the liver or lymph nodes, respectively, leading to preferential internalization by antigen-presenting cells, educating the immune system to respond in an innocuous way. In a mouse model of cow's milk allergy, treatment with glycosylation-modified ß-lactoglobulin (BLG) is effective in preventing the onset of allergy. In addition, s.c. administration of glycosylation-modified BLG shows superior safety and potential in treating existing allergies in combination with anti-CD20 co-therapy. This platform provides an antigen-specific immunomodulatory strategy to prevent and treat food allergies.