Ovalbumin-lysozyme interaction

Possible stabilization by nonspecific means would be relevant to food systems. No stabilization was observed by DSC for the ovalbumin-lysozyme interaction (Donovan and Beardslee, 1975). Nonspecific interactions with heat-stable proteins (including ovomucoid) reportedly stabilize heat-susceptible proteins against inactivation, possibly by reducing diffusion-limited interactions between unfolded chains and resulting aggregation, in several model systems (Minton et al., 1982). In this case, the mechanism is different. 

Mixture of proteins (Myoglobin, Ovalbumin, Lysozyme and Chymotrypsinogen) Purification Hydrophobic Interaction [52]... 

Separations in hydrophobic interaction chromatography have been modeled as a function of the ionic strength of the buffer and of the hydrophobicity of the column, and tested using the elution of lysozyme and ovalbumin from octyl-, butyl- and phenyl-Sepharose phases.2 The theoretical framework used preferential interaction analysis, a theory competitive to solvophobic theory. Solvophobic theory views protein-surface interaction as a two-step process. In this model, the protein appears in a cavity in the water formed above the adsorption site and then adsorbs to the phase, with the free energy change... 

Figure 2.9 Hydrophobic-interaction chromatography of proteins. (A) Ammonium sulfate gradient from 2.16 to 0 M (B) ammonium sulfate and tetrabutylammonium bromide gradients from 2.16 to 0 M and from 0 to 10 mM, respectively (C) ammonium sulfate and tetrabutylammonium bromide gradients from 2.16 to 0 M and from 0 to 20 mM, respectively (D) ammonium sulfate and tetrabutylammonium bromide gradients from 2.16 to 0 M and from 0 to 40 mM, respectively. Chromatography conditions column, silica-bound polyether, 10 cm x 4.6 mm I.D. temperature, 25°C flow rate, 1 ml/min gradient, linear for 30 min background buffer, 50 mM phosphate, pH 6.5. Peaks a, cytochrome c b, ribonuclease A c, /3-lactoglobulin A d, lysozyme e, ovalbumin f, a-chymotrypsinogen A g, fetuin. (Reprinted from Ref. 45 with permission.)...

Recently, PHEMA microspheres have been more and more extensively used for IMAC. Separon-IDA-Fe(III) or Cu(II) was prepared. It was found that Cu(II) interacted preferentially with histidine and tryptophan residues, while Fe(III) preferred phosphate residues, as demonstrated by the separation of lysozyme, ribonuclease A, myoglobin, and transferrin on the Cu(II) column and ovalbumin on the Ee(III) column, respectively.The PHEMA-Congo Red-Cu(II) and PHEMA-Cibacron Blue E3GA-Zn(II) microspheres were applied for adsorption of BSA. Without incorporating the metal ions, the dyed sorbents were already good stationary phases for affinity chromatography. As shown in Fig. 2, the addi-... 

Ionic Strengths If the protein-polymer complex is formed as a result of electrostatic interactions, increased ionic strength should serve to reduce the attraction between the oppositely charged macromolecules, and decrease the precipitation efficiency. This is observed at pH 4.2 in Figures 3 and 4 for lysozyme and ovalbumin, respectively, and in Figure 5 for lysozyme at pH 5.8 and 7.5. 

Other studies included the investigation of the stabilizing effect of sorbitol on hen egg white lysozyme and the use of the self-diffusion coefficient, D, to follow the solution and aggregative properties of lysozyme at different pH, temperature, and protein and salt concentrations. The properties of frozen ovalbumin solutions were studied by NMR relaxation spectroscopy. It is known that the functional properties of muscle proteins are affected by protein interactions with ions, and NMR was used to assess protein/water, protein/salt, and protein/protein interactions in myofibrillar protein solutions. Previous X-ray and NMR studies on collagen and peptides were reviewed by Mayo and, more recently, such types of system were characterized by high-resolution H and C NMR. °0 The structure, hydration state, and nature of the interactions between water and gelatin were determined by time domain NMR. ... 

The adsorption process is normally monitored by the decrease of interfacial tension (the increase of interfacial pressure). Steady-state values of interfacial tension are reached in several hours, even in the case of proteins with low surface activity, such as lysozyme and ovalbumin [18]. However, the situation is different for parameters of interfacial rheology, such as interfacial viscosity. Measurements with a variety of proteins have shown that a steady-state interfacial viscosity is never reached over the normal experimental time scale (several days) [17]. The reason for the larger time scale in interfacial rheology is that this method reflects intermolecular interactions as well as intramolecular rearrangements of adsorbed proteins. 

To and Lenhoff [37] investigated the contribution of protein solubility to retention in HIC using isocratic elution with four commercially available agarose media and four model proteins (ribonuclease A, lysozyme, myoglobin, and ovalbumin). Various retention trends (type of adsorbents, type and concentration of salt, pH) were tested as a function of the properties of each protein and the importance of protein—surface interaction or conformational change for protein binding was found. 

A fluorescence polarization method has been used to compare the association constants of the interactions between k- and osi-caseins and between lysozyme and ovalbumin. The latter interaction is electrostatic in nature. 

In the titration curves of lysozyme in the presence of ovalbumin, ovalbumin only weakly interfered with the complexation of lysozyme and PAA. However, in the egg white system, only 3.4% of the protein is lysozyme. Most of the proteins have net charges opposite to that of lysozyme below the isoelectric point of lysozyme, pH 10.7. The likelihood of interactions among the proteins shifting the critical pH is much greater Fig. 16.8 shows this to occur for all but the highest MW. Why the critical pH of MW 4000000 PAA was not much affected (compare Figs. 16.6 and 16.8) is not understood. However, the absence of a shift is an indication of selective removal of the lysozyme such behavior is desirable in trying to fractionate proteins by precipitation. 

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