Ovalbumin

Ovalbumin is a glycoprotein and the major protein of egg white. It has a molecular weight of 45,000 (Perlmann, G. 1952). Nichol et al. (1985) report on a study of the shape of the ovalbumin molecule. See review by Warner (1954).

Ovalbumin is used in conjugo-immuno-determinations and drug and pharmaceutical processing.

Characteristics of Ovalbumin from Egg White:

Molecular weight: 45,000.

Composition: In electrophoresis ovalbumin is isoelectric at pH 4.6 but there are three components in the crystalline preparation. From the work of Perlmann (1952) it appears that this electrophoretic separation is due to differences in the phosphorus content of ovalbumin, the main component having two atoms of phosphorus/mole protein, the second, one atom, and the third minor fraction no phosphorus. This was demonstrated by treating ovalbumin with phosphatases and measuring the electrophoretic changes. Using a proteolytic enzyme from B. subtilis, Linderstrom-Lang and Ottesen (1947) caused the release of nitrogenous material consisting of small peptides. The resulting protein, called plakalbumin, because of the way it crystallized, contains phosphorus in exactly the same distribution as in ovalbumin. (Perlmann 1952). The C-terminal amino acid residue (proline) has been known for some time (Niu, I., and Fraenkel-Conrat, H., 1955) and Narita and Ishii (1962) found the N-terminal sequence to be: N-acetyl-Gly-Ser-Gly-Leu-Ala. There is one disulfide bond (Warner 1954). Nuenke and Cunningham (1961) showed that the carbohydrate is linked to the protein through an aspartic acid carboxyl group and were able to purify the glycopeptides. Data indicates that the prosthetic group contains five mannose and three acetylglucosamine residues attached to aspartic acid at the glucosamine (Bogdanov et al., 1962).

Stability: Stable at least one year at 2-8°C. Preparations have remained viable for over 5 years.

Storage: Store at 2-8°C.