Thermodynamic studies of partitioning behavior of lysozyme and conalbumin in aqueous two-phase systems

Sousa, Rita de Cássia Superbi de; Coimbra, Jane Sélia dos Reis; Silva, Luís Henrique Mendes da; Silva, Maria do Carmo Hespanhol da; Garcia‐Rojas, Edwin Elard; Vicente, António A.

doi:10.1016/j.jchromb.2009.07.002

Cited by 25 publications

(23 citation statements)

References 11 publications

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“…Egg white proteins are considered model of choice for studying proteins because of their high nutritional and biological value [9]. Conalbumin (CA), one of the main ironbinding monomeric glycoproteins containing D-mannose and D-galactose sugar moiety, is present in egg white.…”

Section: Introductionmentioning

confidence: 99%

pH-Dependent Conformational Transitions in Conalbumin (Ovotransferrin), a Metalloproteinase from Hen Egg White

Rabbani

Ahmad

Zaidi

et al. 2011

Cell Biochem Biophys

188

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Acid unfolding pathway of conalbumin (CA), a monomeric glycoprotein from hen egg white, has been investigated using far- and near-UV CD spectroscopy, intrinsic fluorescence emission, extrinsic fluorescence probe 1-anilino-8-napthalene sulfonate (ANS) and dynamic light scattering (DLS). We observe pH-dependent changes in secondary and tertiary structure of CA. It has native-like α-helical secondary structure at pH 4.0 but loss structure at pH 3.0. The CA existed exclusively as a pre-molten globule state and molten globule state in solution at pH 4.0 and pH 3.0, respectively. The effect of pH on the conformation and thermostability of CA points toward its heat resistance at neutral pH. DLS results show that MG state existed as compact form in aqueous solutions with hydrodynamic radii of 4.7 nm. Quenching of tryptophan fluorescence by acrylamide further confirmed the accumulation of an intermediate state, partly unfolded, in-between native and unfolded states.

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Section: Introductionmentioning

confidence: 99%

pH-Dependent Conformational Transitions in Conalbumin (Ovotransferrin), a Metalloproteinase from Hen Egg White

Rabbani

Ahmad

Zaidi

et al. 2011

Cell Biochem Biophys

188

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“…A casca do ovo é fonte de cálcio e substituto do carbonato de cálcio, que são produtos amplamente utilizados pelas indústrias alimentícias, farmacêuticas, odontológicas e de cosméticos (NAVES et al, 2007). A clara do ovo é fonte de lisozima e conalbumina, que são proteínas de alto valor nutricional e funcional (SOUSA et al, 2009). A albumina usada em suplementos alimentares controla a hipertensão e o ganho de massa muscular (SALVADOR & SANTA, 2002).…”

Section: Introductionunclassified

Recuperação da topografia de ovos por meio da técnica de moiré e calibração independente

Silva¹,

Yanagi²,

Silva³

et al. 2011

Eng. Agríc.

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RESUMO:A recuperação da topografia de ovos por meio de análise de imagens digitais permite, de forma não destrutiva, a estimativa das massas da gema, da clara, da casca e totais, que são produtos amplamente utilizados na esfera industrial. O presente trabalho buscou desenvolver uma metodologia para a recuperação da forma tridimensional de ovos por meio de análise de imagens, em especial usando a técnica de moiré. Foram utilizados ovos de diferentes tamanhos, classificados em: XL (mais de 73 g), L (63 a 73 g), M (53 a 63 g) e S (até 53 g). Em cada teste realizado em laboratório, um ovo, aleatoriamente selecionado, foi iluminado com a projeção de grades, e as imagens foram capturadas e processadas para a obtenção da forma tridimensional do objeto pela técnica de moiré (TM). As dimensões dos seus eixos principais foram medidas por meio de um paquímetro, sendo usadas como referência para calibração da TM. Equações empíricas foram ajustadas para a correção das dimensões, apresentando coeficiente de determinação de 0,961; 0,955 e 0,988. A TM mostrou-se adequada para a recuperação da topografia de ovos, proporcionando erros menores ou iguais a 5,47%, com a clara necessidade de uma calibração independente, nas três dimensões, e sem a necessidade de usar um objeto calibrador. PALAVRAS-CHAVE:análise de imagens, ovo, forma tridimensional. EGGS' TOPOGRAPHY RECOVERY BY MEANS OF THE MOIRÉ TECHNIQUE AND BY AN INDEPENDENT CALIBRATION ABSTRACT:The recovery of the topography of eggs using digital images analysis allows the prediction with a non-destructive and with a non-contact way of the egg mass, yolk, egg white, and eggshell, which are products widely used in the industrial sphere. The present research seeks to develop a methodology to recovery the tridimensional shape of eggs through image analysis, in particular by the moiré technique with the proposition of an independent calibration. For the accomplishment of this research, eggs of different sizes classified in XL (more than 73g), L (63 to 73g), M (53 to 63 g), and S (until 53 g) were used. In each test realized at the laboratory, one egg, randomly selected was illuminated with the projection of grids and the images were taken and processed to obtain the tridimensional shape of the object by moiré technique (TM). The dimensions of its main axes were measured by means of a caliper rule, being used as a reference for the TM calibration. Empirical equations were adjusted for the correction of the dimensions, presenting coefficient of determination of 0.961, 0.955, and 0.988. TM showed to be adequate for recovering the egg topography providing errors smaller or equal to 5.47%, with a clear demand of an independent calibration in the three dimensions, and without any standard object.

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“…Coimbra et al [22] observed that ␤-lactoglobulin partitioned almost quantitatively between the two phases while ␣-lactalbumin was enriched in the top-phase, in ATPS containing PEGs and potassium phosphate. With the egg white proteins lysozyme and conalbumin Sousa et al [33] found, using ATPS formed by PEG 1500 and sodium salts (sodium citrate and sodium sulfate), that lysozyme tends to concentrate in the polymer-rich phase while conalbumin concentrates in the salt-rich phase.…”

Section: Partitioning Results For Peg 1500/sodium Phosphate Atpsmentioning

confidence: 99%

“…On the contrary, with the increase of TLL, the transfer of the biomolecules will tend toward one of the two phases, i.e., the values of K become increasingly distant from 1. This behavior results from the difference in composition between the phases, which engenders changes of entropic and enthalpic effects on the affinity of a given biomolecule toward each phase [32,33]. In that way, the phase composition, expressed by the TLL of the studied systems, can influence the partitioning behavior: an increasing of the TLL is likely to favor the partitioning of the casein hydrolysates.…”

Section: Equilibrium Datamentioning

confidence: 99%

Recovery of casein-derived peptides with in vitro inhibitory activity of angiotensin converting enzyme (ACE) using aqueous two-phase systems

Souza

Coimbra

Oliveira

et al. 2014

Journal of Chromatography B

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Peptides inhibiting the activity of angiotensin converting enzyme (ACE) were obtained by trypsin-catalyzed hydrolysis of bovine milk casein, performed at 37°C, during 1, 2, 5, 8 and 24h. Results of in vitro inhibitory activity ranged between 13.4% and 78.5%. The highest ACE inhibitory activity was evidenced for hydrolysates obtained after 2h of reaction. Aqueous two-phase systems (ATPS) formed by polyethylene glycol of 1500gmol (PEG 1500)+sodium phosphate or potassium phosphates were produced and evaluated, in terms of partition coefficients (K) and extraction yields (y), to recovery the casein hydrolysates at room temperature. In ATPS containing sodium phosphate, the peptides showed a slightly greater affinity toward the bottom salt-rich phase (0.1≤K≤0.9; 5.7%≤y≤47%). In the case of ATPS containing potassium phosphates, these molecules showed substantially greater affinity toward the top polymer-rich phase (137≤K≤266; y≥99%). These results point out extraction using PEG 1500/potassium phosphate ATPS is an efficient technique to recover casein hydrolysates containing ACE inhibitors peptides. Outlined data will be helpful in integrating such unit operation to larger scale processes.

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Thermodynamic studies of partitioning behavior of lysozyme and conalbumin in aqueous two-phase systems

Cited by 25 publications

References 11 publications

pH-Dependent Conformational Transitions in Conalbumin (Ovotransferrin), a Metalloproteinase from Hen Egg White

pH-Dependent Conformational Transitions in Conalbumin (Ovotransferrin), a Metalloproteinase from Hen Egg White

Recuperação da topografia de ovos por meio da técnica de moiré e calibração independente

Recovery of casein-derived peptides with in vitro inhibitory activity of angiotensin converting enzyme (ACE) using aqueous two-phase systems

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