Title: Ovalbumin
Additional Names: Egg albumin
Literature References: The major protein constituent (75%) of egg white from hen's eggs. Mol wt about 45,000. Produced under hormonal control by the bird oviduct. May be isolated and crystallized readily from the filtrate of an acidified mixture of egg white and an equal volume of satd. ammonium sulfate: Sorensen, Hoyrup, C.R. Trav. Lab. Carlsberg 12, 12 (1917). Alternate method: Kekwick, Cannan, Biochem. J. 30, 227 (1936). Can be separated by electrophoresis and chromatography from about ten other minor components including avidin, lysozyme, conalbumin, q.q.v., and ovomucoid. Structure is a complex protein consisting of a single polypeptide chain of about 400 residues (about half of which are hydrophobic), a maximum of two phosphate residues per mole, and an oligosaccharide side chain composed of only mannose and glucosamine residues. Sequences of N- and C-terminal segments: Narita, Ishii, J. Biochem. 52, 367 (1962); Thompson et al., Aust. J. Biol. Sci. 24, 525 (1971). Reviews: R. C. Warner in Neurath-Bailey, The Proteins vol. II, part A (New York, 1954) p 443 sqq; Taborsky, Adv. Protein Chem. 28, 34-50 (1974).
Properties: Needles or elongated prisms, frequently forming rosettes. The crystals usually contain 2 mols protein and 3 mols H2SO4. [a]D20 -30.7°. Coagulation temp 56°. Sol in electrolyte-free water. Combines with salts, acids, and bases. Denaturation can be induced by heating to 56°, by vigorous shaking, by electric current, and by various chemicals, such as acids, ammonia salts, heavy metal salts, and alcohols. All methods produce complete and irreversible denaturation. Isoelectric point: 4.63.
Optical Rotation: [a]D20 -30.7° |