Ovalbumin is a type of albumin, which is a water-soluble and heat-coagulating protein that is widely distributed in plant and animal tissues. The ovalbumin protein constitues fifty percent of egg white, usually found in chicken, and is easily obtained in crystals. Other proteins found in egg white include conalbumin, lysozyme, ovoglobulin and many more. The synthesis of this protein is stimulated by oestrogen, which is a generic term for oestrus producing steroid compounds, the female sex hormones. The mechanism and understanding of this reaction continues to be under research.
The serpins are a widely distributed family of proteins, mostly serine protease inhibitors, which contain diverse functions. It has been found through sequence alignment of the crystal form of alpha-antitrypsin that the serpins share a common highly ordered structure. The alpha-1-antitrypsin structure is the the cleaved form of the archetypal serpin, although the native structure of this protein remains unknown. Ovalbumin and antithrombin III are other members included in the serpin superfamily. A lot of what is known about the ovalbumin protein has resulted from experimental research with alpha-1-antitrypsin and antithrombin III. Alpha-1-antitrypsin, a glycoprotein produced in the liver, is a major antiprotease in the blood that mainly serves as an inhibitor to leukocyte elastase. Antithrombin III is a plasma protein that helps prevent harmful blood clotting.
Ovalbumin is a glycoprotein of 385 residues with a molecular weight of 45000 daltons. The residues include side chains of mannose and glucosamine. The isoelectric point of this protein is 4.6, and is easily denatured at temperatures above 56 degrees Celsius. Other factors contributing to denaturation of this protein are heavy metals, ammonium salts, alcohols, and acids. According to the Worthington Biochemical Corporation web page, ovalbumin is used in conjugo-immuno determinations as well as drug and pharmaceutical processing. The ovalbumin protein can be obtained from chicken egg white or bought from various chemical companies.
Figure 2. This view of ovalbumin shows the largeness of the A chain. The main A chain is highlighted in pink. The residues highlighted in green are part of Chain A, but they remain unknown. The tubular structures are the other domains of ovalbumin, with Chain D located within Chain A, and Chain B on the bottom region of this figure. The uppermost region is Chain C. This just notes an interesting part of ovalbumin's structure, although the details of this will not be discussed in this paper. Perhaps in the near future, the rest of the ovalbumin structure will be completely identified and understood in reaction mechanism and functioin.