Ovalbumin, hen

From electric birefringence measurements it was concluded that the proteins are ordered head-to-tail within the fibril, in a helical configuration (Rogers et al. 2005). The fact that one needs a minimal temperature in order to induce fibrillisation is directly related to the fact that at a certain elevated temperature the protein will partially unfold. Since we have also observed the formation of fibrils at 4°C, after having applied this (partial) denaturation step, the elevated temperature is not essential during assembly. However, at the lower temperature, the assembly was found to be much slower, indicating that temperature affects the kinetics of the assembly process. The relation between the fibrillar type of assembly and the partially unfolded state also has been found for other proteins (e.g., ovalbumin, hen egg white... 

Number of Carbon Resonances Observed in the Spectral-reporter Region of Hen Ovalbumin Glycopeptides... 

Squaraine dyes 10b, 39a, 39b, 41a, 41c, 41d, and 41e were used to measure different proteins such as BSA, HSA, ovalbumin, avidin from hen egg white, lysozyme, and trypsin (Fig. 12) [58]. It is difficult to predict correlations between the dyes structures and the affinity or sensitivity of the dyes for different proteins. All squaraine probes exhibit considerable fluorescence increases in the presence of BSA. Dicyanomethylene-squaraine 41c is the brightest fluorescent probe and demonstrates the most pronounced intensity increase (up to 190 times) in presence of BSA. At the same time, the fluorescent response of the dyes 10b, 39a, 39b, 41a, 41c, 41d, and 41e in presence of other albumins (HSA and ovalbumin) is, in general, significantly lower (intensity increases up to 24 times). Dicyanomethylene-squaraine 41a and amino-squaraines 39a and 39b are the most sensitive probes for ovalbumin. Dyes 41d, 10b, and 41e containing an A-carboxyalky I -group demonstrate sufficient enhancement (up to 16 times) in the presence of avidin. Nevertheless, the presence of hydrolases like lysozyme or trypsin has only minor effects on the fluorescence intensity of squaraine dyes. 

To test DC-specific targeting, model antigens such as hen egg lysozyme (HEL) and ovalbumin (OVA) were covalently linked to anti-DEC-205 antibodies and injected into mice. This resulted in antigen loading of the lymph node DCs,... 

Fig. 2.1. Semilogarithmic plot of molecular weight (Mr) of marker proteins vs relative mobility (Rf) of marker proteins in gels of different acrylamide concentrations %T. Proteins 1 aprotinin (6.5 kD) 2 lysozyme (14.5 kD) 3 soybean trypsin inhibitor (21.5 kD) 4 carbonic acid anhydrase (31 kD) 5 hen ovalbumin (45 kD) 6 bovine serum albumin (66 kD) 7 phosphorylase b (97.4 kD) 8 8-galactosidase (116 kD) 9 myosin (205 kD)...

Further evidence for the presence of /8-D-linked D-mannose in the inner core of ovalbumin was provided by the results obtained on use of purified enzymes from hen oviduct.20 a-D-Mannosidase released four residues of D-mannose from the molecule of a glycopeptide having D-mannose hexosamine L-asparagine ratios of 5 2 1, whereas /3-D-mannosidase had no effect thereon. /3-D-Mannosidase did, however, remove the remaining D-mannose residue. It would appear that the resistant core has structure 3. 

Secretion of nonglycosylated macromolecules in the presence of tunicamycin has also been investigated in a number of other cells. Rat-liver cell-secretion ol albumin (a carbohydrate-free protein), transferrin, and a-acid glycoprotein was not inhibited, and, in chick-liver cells, only a decrease by 10-25% in the secretion of transferrin and the apoprotein B chain of very-low-density lipoprotein was noted.463,464 The secretion of ovalbumin (a glycoprotein) from hen oviduct was not blocked by tunicamycin.465... 

Proteins present in whole egg, yolk, and albumen (egg white) are excellent sources of nutrients, and they possess valuable functional properties. Shell eggs consist of 8-11% shell, 56-61% albumen, and 27-32% yolk. The solid content of albumen is about 11-13%, depending on the strain and on the age of the hens, and the solid content of yolk is about 52-53.5%. Albumen solids contain mainly protein, whereas lipids are the major constituents of egg yolk (92). Yolk can be separated by centrifugation into sedimented granules and a supernatant, plasma. The granules contain the major part of the yolk proteins. The main proteins in albumen and yolk are ovalbumin, ovotransferin, lysozyme, ovomucoid, ovomucin, and immunoglobulin Y (93). 

Fig. 5.—Structure of Hen-ovalbumin Glycopeptides GP-IV and GP-V (Ref. 96), GP-III-B (Ref. 97), and GP-VI (Ref. 98). [GP-V is identical to that of Taka-amylase A glycan (see Fig. 4) GP-IV and GP-V are identical to GP-5 and GP-6 glycopeptides from ovalbumin, as described by Conchie and Straehan.99]...

Fig. 16.—Structure of Hen-ovalbumin Glycopeptide of Oligomannosyl-N-acetyl-lae-tosaminie Type.97,117 (GP-III-A is identical to GP-4-B as described by Conchie and Stra-chan.99)...

The enzymatic synthesis of a hybrid type oligosaccharide on the hen ovalbumin with 13C-enriched galactose allowed the measurement of the 13C-NMR spectra of the whole glycoprotein and additionally, the determination of the correlation times of the protein and the oligosaccharide to 25 ns and 40-80 ns, respectively [168]. This implies that the carbohydrate, at least in its terminal monosaccharide constituents, has a much higher flexibility than the protein, and its flexibility is only little impeded by the attachment to the protein. 

Mapping the IgE epitopes of Gal d 2, the major hen egg white ovalbumin causing allergic reactions particularly in children, was performed by SPOTs technology... 

The crystal structure of native hen ovalbumin shows an intact reactive center loop in the form of an exposed a-helix of three turns that protrudes from the main body of the molecule on two peptide stalks. The ovalbumin structure includes four crystallographically independent ovalbumin molecules and the position of the helical reactive center loop relative to the protein core differs by 2-3 A between molecules. Although this shift is probably due to the different environments of the helices in the crystal lattice, it suggested that the reactive center loop is flexible in solution. Structural studies of serpins in various conformations have shown how the exceptional mobility of the serpin reactive center loop and their unique flexibility is essential for function. In contrary to inhibitory serpins, ovalbumin does not show evidence for a large conformational change following cleavage at its putative reactive center and appears to have lost the extreme mobility which is characteristic for its inhibitory ancestors. 

Ibrahim, H.R. 1997. Insights into the structure-function relationships of ovalbumin, ovotransferrin, and lysozyme. In Hen Eggs Their Basic and Applied Science (T. Yamamoto, L.R. Juneja, H. Hatta, and M. Kim, eds), pp. 37-56. CRC Press, Boca Raton. 

Based on fractionation data for hen egg white proteins including hen egg white lysozyme, ovalbumin, and avidin. 

Figure 2. SDS gel electrophoresis of the products of partial cystine cleavage for several test proteins. A. molecular weight standards, B. yeast alcohol dehydrogenase. C. P-lactoglobulin, D. hen egg lysozyme, E. ovalbumin, F. calf fetal serum fetuin. Molecular weight standards are indicated by arrows on the left side of the gel and are bovine serum albumin (66,300), bovine liver glutamate dehydrogenase (55,400), porcine muscle lactate ddiydiogenase (36,500), bovine erythrocyte carbonic anhydrase (31,000), soybean trypsin inhibitor (21,500), hen egg lysozyme (14,400), bovine lung aprotinin (6,000), unresolved bovine pancreatic insulin A and B chains.

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