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Contents 1 Ovalbumin 2 Structure 3 Function 4 Properties 5 Disease 6 Biotechnological use 7 Relevance 8 References

Ovalbumin

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Ovalbumin (1OVA) is the main protein of the avian egg white. This protein represent approximatively 60% of the total protein. Its exact function is still unknown but it is thought to be a storage protein for the developing foetus. Storage proteins are a reserve of ion and amino acid which can be used by organisms.

Ovalbumin has sequence similarities and three dimensional homology with the serpin superfamily. Serpin are serine protease inhibitor but some of them have also non inhibitory roles, such as ovalbumin which belongs to the subgroup known as ov-serpins (ovalbumin-related serpins) or class B serpins.

In the human, ov-serpins include 13 proteins involved in the regulation of inflammation, apoptosis, angiogenesis, and embryogenesis. It suggests that “newer” serpins, such as ovalbumin, have contributed to vertebrate adaptation.

Structure

Ovalbumin is a 42.8kDa protein consisting on 386 residus. Ovalbumin has 4 homologous units : A, B, C and D. It has a characteristic consisting to 8-9 alpha helix and three beta sheets. Ovalbumin lacks a conformational change in the reactive center loop which confere the characteristic of a protease inhibitor to the serpin family ^[1]. Ovalbumin tends to change into a more stable protein: S-ovalbumin.

Function

Ovalbumin take a key role during the eggshell formation where it could serves as an effective stabilization agent for some precursors and could prevents the mineralization of the eggshell at the early state of development.

Properties

Ovalbumin can coagulated when heated: in solution at a concentration higher than 0.1% heated, a coagulum is formed ^[2].

Its isoelectric point has been established at 4.7 (pI=4.7). ^[3]

Disease

Ovalbumin is one of the major allergens causing some children under 4 years old being highly sensitized to egg white. Ovalbumin sensitization is related to atopic dermatitis and children with ovalbumin sensitization are more likely to have asthma with atopic dermatitis, atopic dermatitis with allergic rhinitis, or atopic dermatitis, but are less likely to have asthma with allergic rhinitis. Atopic or allergic diseases causes a decrease of the titer of ovalbumin-IgG4 antibodies but an increase of ovalbumin-IgE antibodies.

Biotechnological use

Ovalbumin is used to induce asthma in rat, mouse and guinea pig to assess the in vivo efficacy of anti-asthma drugs.

Ovalbumin is also used by industries and for the research about vaccination. Indeed, this glycoprotein is enough large and complex to be immunogenic. Consequently, it is widely used as an antigen for immunization research.

Relevance

References

1. ↑ James A. Huntington & Penelope E. Stein (2001), "Structure and properties of ovalbumin", Journal of Chromatography B: Biomedical Sciences and Applications Vo756, p189–198 S0378-4347(01)00108-6
2. ↑ Donald D. Bills and al. (2014) Biotechnology and Food Safety: Proceedings of the Second International Symposium, UM-USDA-DUPONT, 381 p. GoogleBook
3. ↑ Stephan E. Wolf and al. (2011),"Strong stabilization of liquid amorphous calcium carbonate by ovalbumin: gaining insight into the mechanism of ‘polymer-induced liquid precursor’ processes", J. Am. Chem. Soc., no133 doi:10.1021/ja202622g