Chicken egg lysozyme

Useful internal sequences and useful structural information can be gathered from this technique. However, like any digestion procedure, there is no guarantee that useful information will be obtained in every case. The sequences obtained for chicken egg lysozyme (data not shown) gave amino terminal sequence for every band. Given that lysozyme is a small protein with four disulfide bands and that all but two of the eight cysteine residues are located in the C-terminal half of the molecule, this result is not surprising. 

In one of the pioneering studies, conformational changes were induced in a model protein (bovine ubiquitin) by adding methanol to aqueous acidic solutions of the analyte [61], Using HDX in combination with ESI-MS, it was possible to follow conformational changes in bovine ubiquitin and in chicken egg lysozyme (due to the reduction of the disulfide... 

Figure 12.9 MALDI-TOF mass spectrum of chicken egg-white lysozyme. The peak at 14,307.7578 daltons (amu) is due to the monoprotonated protein, M+H+, and that at 28,614.2188 daltons is due to an impurity formed by dimerization of the protein. Other peaks are various protonated species, M+H rH ...

The AB + C case is illustrated by the works of Kabanov et al. [296], who investigated mixtures of PEO-PMANa with P4VPQ, of Gohy et al. on the pH-dependent complexation of P2VP-PEO with PSS [297,298], and of Kataoka and coworkers on PEO-PAspA/chicken egg white lysozyme mixtures [299, 300]. In all these studies, the resulting micelles contained an IPEC core and a PEO corona. 

Fig. 6 Transition temperature of protein unfolding measured by CE and CD. Proteins lysozyme from chicken egg (LYS), a-lactalbumin from human milk (LAL-h), a-lactalbumin type III from bovine milk (LAL-III), cytochrome c from bovine heart (CYT), recombinant dihydrofolate reductase (DHFR).

Figure 4.2. GenBank format for nucleotide sequence of chicken egg-white lysozyme.

MATERIALS. Ribonuclease A (RNase A) (bovine pancreas), cytochrome C (Cyt. C) (horse heart), lysozyme (chicken egg white), myoglobin (sperm whale), P-lactoglobulin A... 

The bird lysozymes c, of which chicken egg white lysozyme (CL) is the most extensively studied example, provide an ideal system to recreate evolutionary intermediates and to study structure-function relationships of reconstructed ancestral proteins. Three major considerations qualify the avian lysozyme system for reconstruction of evolutionary pathways (1) the biochemistry of the enzymes has been extensively studied and well characterized,3,4 (2) there are many natural variants available from other birds, and homologous comparisons can be ensured since lysozymes for all game birds are encoded by a single gene,5 and (3) the three-dimensional structure of CL has been resolved at the atomic level, which allows for structural interpretation of the mutational impact.2,4 Proteins representing the ancestral, evolutionarily intermediate, and derived states of chicken and related bird lysozymes are made and characterized as described below. 

The CL variants are constructed by site-directed mutagenesis of the cDNA for chicken egg white lysozyme and heterologously expressed in yeast behind a regulated hybrid promoter.6... 

Fio. 2. Subcloning and expression system for chicken egg white lysozyme. See the text (section on subcloning) for further details. RF, Replicative form. 

Lysozyme Obtained from extracts of purified chicken egg whites. Generally prepared and used in the hydrochloride form as a white powder. Major active principle lysozyme. Typical application used as an antimicrobial in food processing. 

Chicken egg white lysozyme (LZM) does not possess exposed methionyl residues, and it has six tryptophan residues, three of which, located at positions 62,108, and 111 are readily oxidizable with ozone and are built-in the LZM active center (D14). Tryptophanyl residues are also the first reacting moieties upon treatment of LZM with the MPO-Cr-H2C>2 system (at pH 4.5). The reaction occurs in several stages. In the first stage, which occurs when 1.4-1.8 mol of H2O2 for 1 mol of LZM is used, LZM loses its enzyme activity, but no derivative distinguishable from the native protein on the polyacrylamide gel electrophoresis is formed. The inactivation may be prevented by addition to the reaction medium A-acetylcysteine or... 

Figure 4 The electrostatic distributions of a-lactalbumin (lALC) (a) and chicken egg-white lysozyme (ILZl) (b) calculated by Delphi and presented by Grasp. Both surfaces of calcium-binding protein a-lactalbumin are mostly negatively charged (a) (in red) while the surfaces of noncalcium binding protein lysozyme (b) are mostly positively charged (in blue)...

The egg white of the Australian black swan, Cygrms atratus, contains two forms of lysozyme c and g types. The X-ray structure of the g type has been determined by Isaacs etal. (1985) at 0.28-nm (2.8 A) resolution. A comparison of the structures of chicken egg white, goose egg white (g type), and bacteriophage T4 types of lysozyme has been made by Weaver et al. (1985), and the evolutionary relationships have been discussed in light of this study. This work is discussed in Section X. 

E.L. Forsythe, R.A. Judge, M.L. Pusey, Tetragonal chicken egg white lysozyme solubility in sodium chloride solutions, J. Chem. Eng. Data 44(1999) 637-640. 

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