Ovotransferrin – Multifunctional protein: Structure, bioactivity, and industrial potential
Piotr Fijałkowski, Oleksandra Pryshchepa, Rudi van Eldik, Paweł Pomastowski
Abstract
Chicken eggs represent a rich and comprehensive source of essential nutrients, including proteins, lipids, carbohydrates, vitamins, and minerals. Proteins account for approximately 12-15 % of the total egg content. One of the most valuable egg white proteins (EWP) is ovotransferrin (OTF), which comprises 12-16.5 % of total EWP. OTF is a protein from the transferrin family with diverse biological functions, including antibacterial, anticancer, antiviral, and antioxidant activities. Like other transferrin family proteins, OTF has a two-lobed structure (N-terminal and C-terminal), each composed of two domains and containing a single metal-binding site. The protein exists in two forms: the apo form (without a bound metal ion) and the holo form (with a bound metal ion). Sharing approximately 50 % sequence identity with lactoferrin, a protein renowned for its health-promoting properties, OTF remains underrecognized despite its similar structure and potential for even superior bioactivity, warranting further investigation. OTF can be isolated using methods such as precipitation, column chromatography, membrane techniques, or electrophoresis. However, not all of these techniques are readily scalable for industrial applications. Therefore, this paper aims to provide a comprehensive review of OTF, focusing on its structure, biological functions, factors affecting its activity, methods of isolation and analytical techniques employed in OTF research.